Anatomical, Histological and Histochemical Studies on Some Organs of True Desert Rodents in the Egyptian Habitats

The Egyptian Journal of Hospital Medicine (2008) Vol., 33: 578– 306

Anatomical, Histological And Histochemical Studies On Some Organs Of True Desert Rodents In The Egyptian Habitats

Boshra A. El- Salkh*, Zaki T. Zaki** Mohammad I. Basuony** and Hanaa A. Khidr* Department of Zoology, Faculty of Science, Al-Azhar University for Girls(1) and Boys(2)

Abstract

Aim of the work: The present study aimed to compare between the anatomy, histology and histochemistry of two species belonging to two different families namely Muridae and Dipodidae. Muridae is the largest family of rodents in the world; it is represented in this work by fat sand rat Psammomys obesus. Four-toed jerboa Allactaga tetradactyla represents the other family, Dipodidae. Psammomys obesus lives in coastal presaharan region; the preferred habitat is saline marshes and wadis where halophytic plants were abundant. However, Allactaga tetradactyla, inhabites the salt marshes and clay desert areas of coastal plains. Material and methods: The investigated animals were collected from desert, weighed and transferred alive to the laboratory in separate cages then anaesthetized with ether, after which they were carefully dissected, organs are taken out and prepared for the histological and histochemical studies. The nucleocytoplasmic index of liver cells was calculated, kidney weighed and the relative thickness of cortex, outer and inner medulla was measured and total glomerular number was recorded. Results: The liver, as in mammalian species, is consists of five separate lobes. The mitotic index of Psammomys obesus is smaller than that found in Allactaga tetradactyla. This may be due to the increased activity of Allactaga tetradactyla. In the kidney, the cortex is classified into three regions namely superficial, midcortical and juxtamedullary zones. Both number and diameter of glomeruli, glomerular volume and relative glomerular blood volume is greater in Psammomys obesus than that in Allactaga tetradactyla. Conclusion: These observations indicate the ability of Psammomys obesus to produce highly concentrated urine than that of Allactaga tetradactyla. Key words: Desert Rodents, Histochemical, Liver, Kidney

Introduction

Fat sand rat Psammomys obesus lives urine show it is up to four times as salty as in the coastal and presaharan regions. They sea water (Happold, 1984) preferred the habitats of salt marshes and The previous author added that, the wadis where halophytic plants are abundant higher costant relative humidity of the (Zaime and Guatier, 1989 and Degan 1993). burrows reduces water evaporation loss, They build a network of shallow burrows where at night, burrow temperature are and because they are frequently diurnal, warmer than outside. they may be seen to feeding on halophytic Fat sand rat Psammomys obesus is plants. This kind of activity is only possible normally normoglycemic when eating provided sand rats possess special desert vegetation but when allowed free mechanisms for staying cool, or for access to standard laboratory foods show obtaining water which may be used for obesity, hyperinsulinemia, hyperglycemia evaporative cooling. The key to their and occasionally ketoacidosis (Marquie et success seems to be their ability to eat the al., 1984). succulent leaves of halophytic plants and Four-toed jerboa Allactaga tetrad- then eliminate the excess salts in a more actyla is restricted in coastal areas in Egypt concentrated urine. Measurements of this he portal veins, hepatic artery, bile duct and

778 Boshra A. El- Salkh et al also a lymphatic vessel lying in a small mammalian species had been typical bean- amount of connective tissue such as in shaped appearance characteristic of the Meriones hurrianae and tatera indica unipolar mammalian kidneys. The kidney (Purohit and Ghosh, 1963). consists of superficial capsule, outer cortex A. tetradactyla feeds primary on seeds and inner medulla. The outer cortex is and succulent vegetation especially plants highly vascular; the inner medulla is with milky juices, but it also has been slightly thick and less vascular. Both cortex known to feeds on insects. It does not drink and medulla are built up of different tubule water at all, but instead lives on metabolic structures (El-Naggar, 1989). water produced by the chemical breakdown The nephron is the functional unit of of food (MacDonald, 1984). A. tetradactyla the kidney; each nephron consists of has been beneficial for controlling crops by corpuscle, proximal convoluted tubules, preying on insects; jerboas keep the post loop of Henle, distal convoluted tubules and population low so the effect of insect collecting tubules. Bowman's capsule is predation on crop is reduced. formed of two thin cellular layers, an inner Basal metabolic rate of A. tetradactyla visceral layer and an outer parietal one, is 68% less than that of white rat feeds which is a simple squamous epithelium (Hendrickson,1983). Atemperature increase resting on basal lamina (Safer et al., 1990). of 40o C kills white rats but only cause The visceral layer is formed of flattened sleeping jerboas to salivate. The life span of epithelium (Zaki, 1993). A. tetradactyla is less than two years. Also, The loop of Henle consists of two the known geological range of the dipodids limbs, thick ascending and thin descending is Pleistocene to Recent in North Africa limbs. The descending limb extends into the (Nowak, 1991; Wilson and Reeder, 2005), inner medulla but the thick ascending limb suggesting that A. tetradactyla is a fairly extends only in the outer medulla (Kaissling recent species on the geological time scale. et al., 1975). The liver is a dark red or reddish Hickman et al. (1984) stated that the brown, the colour caused by a very rich varying ability of different mammals to blood supply. The hepatic lobule is a form concentrated urine is closely related polygonal with a central vein and portal with the length of the loop of Henle. They peripheral canals at the corners. The liver showed that the bear which has no need to tissue is divided into lobules each of which conserve water in its aquatic habitat, has is surrounded by a connective tissue sheath short loops and can concentrate its urine to containing of elastic fibers (Lesson et al., only approximately twice that of the blood 1988). Hepatic cells are polygonal and the plasma of humans, with relatively longer nuclei are spherical or ovoid with a regular loops which concentrate urine 4.2 times that surface and show considerable variation in of the blood plasma. Desert animals have size from cell to cell. Each nucleus is much greater urinoconcentrating power, the vesicular in type with prominent scattered camel can produce urine 8 times as the chromatin granules and one or more plasma concentration, the gerbil 14 times nucleoli (Novikoff and Essner, 1960). At and generally all mammals can produce the surface adjacent to a sinusoidal space, concentrated urine by means of a counter the hepatic cell is separated from the wall of current multiplier system localized in the vascular channel by a narrow perisinusoidal loop of Henle. In the fennec fox Vulpes space, at this surface; the plasma membrane zerda, the daily urine production is of the hepatic cell is covered by numerous considerably reduced mounting to only long microvilli (Lesson et al., 1988). 59% of the expected level (Younis, 2008 The portal area comprise branches of and Basuony et al., 2009). the portal veins, hepatic artery, bile duct The kidney of the jerboa is unipolar and also a lymphatic vessel lying in a small one, similar to that of other small rodents amount of connective tissue such as in but with characteristically very long papilla Meriones hurrianae and tatera indica in the desert rodents (Basuony, 1993). (Purohit and Ghosh, 1963). However, other mammalian species such as According to Lesson et al. (1988) and bats have short papillae (Zaki et al., 1994). Zaki et al. (1994), the kidney of the Histochemically, the basement membrane

588 Anatomical, Histological And Histochemical Studies On…….. of the renal structure as well as, the brush (in more than one direction) of each nucleus border of the proximal convoluted tubules and cell, then the volume of nuclei and cells epithelium are PAS positive (Lesson et al., were calculated as sphere. The nucleocyt- 1988 and Basuony, 1993), also the oplasmic index (NP) was calculated glomerular cells are PAS positive (Foster according to the equation of El–Banhawy et and Riad, 1963). al. (1972): NP = VN / VC - VN Material and Methods Where VN is the volume of the nucleus and VC is the volume of the cell. The investigated animals include two For histochemical studies, Periodic acid desert rodents belonging to two different Schiff’s reagent (PAS) was applied to families. Muridae is the largest family of demonstrate the carbohydrates (Mc Manus, rodents in the world; this family is 1946). represented in this work by fat sand rat After dissection, the kidneys of each Psammomys obesus. Four-toed jerboa sacrifices animal was sectioned longitude- Allactaga tetradactyla represents the family nally and placed in Bouin’s fixative for called Dipodidae. According to Osborn and histological purposes. The other kidney Helmy (1980), Psammomys obesus has weighed and one half of this kidney was three subspecies, the first subonecies postfixed for five minute in 10 % formalin namely obesus was collected from Western (Altaschuler et al., 1979). The relative Desert, the second subspecies terraesanctae thickness of cortex, outer and inner medulla from north Sinai and the third one nicoli of the kidney was measured using from Eastern Desert. The second species, calibrated eye piece on a dissecting Four-toed Jerboa Allactaga tetradactyla, microscope. The total number of glomeruli was collected from Mersa Matrouh (coastal in a mid–sagital longitudinal section was belt of the Western Desert). The specimens also estimated. According to Altaschuler et were weighed and transferred alive to the al. (1979), these measurements were laboratory in separate cages. factorized by kidney weight because of the For gross anatomy, the species were variation in animal size. The ratio of anaesthetized with ether, after which they medulla to cortical thickness is one were carefully dissected and examined. indicator of the species urine concentrating Anatomy of each rodent includes liver capacity (Munkacsi and Palkovits, 1965). kidneys. The liver was weighed in order to The relative glomerular blood volume calculate the hepatosomatic index (HSI) (RGBV) was calculated according to HSI = Weight of liver in grams x 100/ method of Palkovits and Zolani (1963) Weight of animal in grams. using the formula: For histological studies, other V= T /6 (LB)3/2 specimens of each studied species were Where V is the glomerular volume, T is a anaesthetized, quickly dissected and the constant equal to 3.14, L is the long organs previously mentioned were taken glomerular axis and B is the short out and washed in physiological saline glomerular axis. solution (0.9 %). After which the required RGBV = V X N organs were fixed in Bouin’s solution for Where, N is the average number of about 24 hours. Small pieces of each glomeruli. studied organs were then preserved in 70 % ethyl alcohol, dehydrated in graded series Results of alcohol, cleared in xylene and embedded in paraffin wax as usual. Sections of 4–6 µ Anatomical observations thickness were mounted on clean glass 1- The liver slides and stained with Harris haematoxylin The liver of the two studied rodents and Eosin (Hx&E) for general structure and consists of five separated lobes, right and Mallory trichrome stain for connective left central lobes, left lateral lobe, caudate tissue (Pearse, 1968). and Spigelian lobes. The left lobe is the For quantitative study we measured at largest, the right central lobe is larger than least the diameter of one hundred liver cells the left, and the Spigelian lobe is smaller

589 Boshra A. El- Salkh et al than the caudate lobe. The investigated 64.1 in Allactaga tetradactyla (Table 2). species had gall bladder which lies in a The ratio of medullary thickness to cortical depression in the right central lobe of the thickness is about 5.59 % in Psammomys liver. obesus and 2.9% in Allactaga tetradactyla (Table 2). 2- The kidneys The kidney of the studied rodents is Histological observations bean like structure, lying behind the 1- The liver peritoneum in the posterior region of the The liver is a compound tubular gland upper abdomen, one kidney on each side of covered by a thin peritoneal epithelium the upper lumbar vertebra. Each kidney is formed of flattened cells resting on enclosed by a fibroconnective tissue basement membrane of fibroconnective capsule. It is characterised by one long tissue composed of collagenous fibers with papilla, so, the investigated rodents are relatively few cells most of which are called unipolar mammalian kidney. The fibroblasts. Each lobe is subdivided by body weight in Psammomys obesus is about connective tissue into polyhedral lobules 133.6 ± 29.1 g which is greater than the and the interlobular connective tissue is body weight in Allactaga tetradactyla that restricted to the portal canal at the angle of weighed 48.3 ± 9.01 g. The kidney weight the lobules. in Psammomys obesus is about 0.93 g and In Psammomys obesus, the hepatic that of Allactaga tetradactyla weighted lobule is prismatic in shape with a central about 0.29 g. The ratio of kidney weight to vein forming its central axis. It is built up of body weight in Psammomys obesus is about columns of hepatic cells, hepatocytes, 0.83 and in Allactaga tetradactyla is about which radially arranged from the central 0.60 (Table 1). vein to the periphery of the lobule (Fig. 1). The cross section of kidney showed The hepatocytes are polygonal in shape, two anatomical distinct regions, the outer each cell possesses a distinct limiting mem- cortex and inner medulla, both terminate by brane and a clump of basophilic material to renal papilla. The renal cortex is reddish give a slightly basophilic cytoplasm (Fig. brown in colour and varied in thickness 2). The mean of hepatosomatic index of from 3.3 mm in Psammomys obesus to 1.8 Psammomys obesus is about 4.10 ±1.33. mm in Allactaga tetradactyla. It was found Nuclei of hepatocytes are spherical or ovoid that the ratio of the renal cortical thickness with regular surface and show a to the kidney weight (in g) is equal to 3.3 considerable variation in size from cell to and 1.8 mm/g in Psammomys obesus and cell. The mean nucleocytoplasmic index of Allactaga tetradactyla respectively (Table hepatocytes of Psammomys obesus is 1). measured about 56.37 ± 20.69 µ while the The medulla is divided into outer and mitotic index is measured about 68.28 ± inner subregions. The thickness of the outer 10.23 µ (Table 3). Binucleated cells are medulla in Psammomys obesus is about 1.5 present; each nucleus has prominent mm while in Allactaga tetradactyla is about scattered chromatin granules with one or 1.9 mm. Striking difference appeared when more nucleoli and stain less intensely than the thickness of the outer medulla is nuclei of other cells in the liver. The factorized by the kidney weight (in g). For columns of hepatocytes are separated by each species, the average ratio of blood sinusoids which take the same radial Psammomys obesus is 1.61 mm/g and 3.1 direction as the hepatocytes. Blood sinuso- mm/g in Allactaga tetradactyla. The inner ides are scattered between the hepatocytes, medulla was recognized by external portion so that, their walls are formed by the of papilla. The mean length is about 6.8 mm hepatocytes (Fig. 3). and 3.4 mm in Psammomys obesus and Outside the lobules, at certain angle Allactaga tetradactyla respectively (Table lie portal islands of connective tissue, each 1). contains a branch of hepatic artery, portal The percentage of length of the inner vein and bile duct with lymphatic vessels. medulla when compared to the whole The largest structure usually is the branch medulla is 79.6 in Psammomys obesus and of hepatic portal vein. The smallest in size

590 Anatomical, Histological And Histochemical Studies On…….. is the artery; the hepatic artery and bile 2- The kidneys ducts are intermediate in size and are lined In Psammomys obesus, the kidney is by cuboidal epithelial cells. enveloped by a capsule formed of thin Sinusoidal spaces differ from fibroconnective tissue. The kidneys consist capillaries by increased diameter. Two main of an outer region, cortex, and an inner types of cells with intermediate forms, are medulla which extends to the ureter by present in the sinusoidal lining of the liver. renal papilla. The kidney is a compound The first type is the endothelial cell which tubular gland formed of large number of is small, elongated, darkly stained nucleus urineferous tubules; each urineferous tubule and greatly attenuated cytoplasm. The consists of a large number of nephric units second type is kupffer cell which has and collecting tubules. The nephric unit is relatively large oval nuclei with formed of different structures forming cytoplasmic arms (Fig. 3). several segments. Malpighian corpuscle, the Histochemically, the liver gives PAS first segment is composed of glomerulus positive reaction due to the secretion of and Bowman's capsule, the proximal neutral mucosubstance (Fig. 4). convoluted tubules, loop of Henle and distal In Allactaga tetradactyla, the convoluted tubules (Figs. 8-9). structure of liver is similar to that in The renal (Malpighian) corpuscle is a Psammomys obesus except slight spherical structure formed of glomerulus differences. The lobulation of liver cells are which is enclosed by Bowman's capsule. less distinct from the central vein than of The Bowman’s capsule is formed of two Psammomys obesus, so that, the column of thin cellular layers, an outer parietal layer hepatocytes is polygonal in shape as in and an inner visceral layer. The parietal one Psammomys obesus with distinct membrane enclosing a narrow space, the urinary space, (Fig. 5). Nuclei are rounded, strongly which is continuous with the lumen of the basophilic and the cytoplasm is proximal convoluted tubules. The second eosinophilic. Binucleated cells are present layer, the visceral layer, is formed of (Fig. 6). flattened squamous epithelial cells. The The mean of hapatosomatic index of visceral layer is a closely nests glomerular Allactaga tetradactyla is about 5.27 ± 0.83 capillaries, but the cells are greatly which is larger than that in Psammomys modified and do not form a complete sheet, obesus. these cells are called podocytes. The mean nucleocytoplasmic index of The cortex is composed of several hepatocytes of Allactga tetradactyla is layers of glomeruli which are closely measured about 75.34 ± 31.25 µ which is arranged (Fig. 8). This is due to the greater than that of Psammomys obesus and thickness of the cortex that measured 1.20 the mean of mitotic index is measured mm and the total number of glomeruli was about 45.85 ± 19.21 µ that lesser than that recorderd (670 glomeruli). Superficial, in Psammomys obesus (Table 3). midcortical and juxtamedullary types of The portal space is very similar to that glomeruli are found (Figs. 10-11). The of Psammomys obesus which contains a juxtamedullary glomeruli were approxi- branch of hepatic artery, portal vein and mately 1.5 and 1.8 times greater in average bile ducts with a lymphatic vessels. The diameter than midcortical and superficial largest structure usually is a branch of the glomeruli respectively. The great number of portal vein, the smallest structure is the glomeruli observed in the superficial region hepatic artery and the bile duct is was about 267 (39.8 %) while in the intermediate in size and its lining is of midcortical was 282 (42%) and 121 (18 %) cuboidal epithelium. The sinusoidal space in the juxtameduulary glomeruli (Table 4). as in Psammomys obesus contains two The average diameter of glomeruli in the types of cells, the first type is endothelial superficial region was 35.7 ± 7.0 µ while in cell and the second types Kupffer cell (Fig. midcortex it was 42.8± 9.9µ and juxtame- 7). For mucosubstance study, the cytoplasm dullary glomeruli was 66.5 ± 4.2 µ (Table gave PAS positive reaction. 5).

591 Boshra A. El- Salkh et al

The average glomerular volume of the epithelial cells (Fig. 12). The ground superficial, midcortical and juxtamedullary cytoplasm was homogenous eosinophilic in glomeruli were about 1.72x109 µ3, 7.6 these cells and their nuclei are limited with x109µ3 and 40.8x109µ3 respectively. The distinct basophilic nuclear membrane and glomerular volume of the juxtameduulary each nucleus has a single nucleolus. glomeruli was approximately 23.7 and 5.3 At the vascular bundle, there are times greater in average diameter than in venous and arterial vasa recta beside to thin superficial and midcortical glomeruli (Table limb, the latter can be distinguished from 5). The relative glomerular blood volume the arterial vasa recta by the strongly (RGBV) of the juxtamedullary glomeruli stained PAS of the basal lamina of the was measured 2.6 x1012 and 2.16 x1012 in arterial vasa recta as compared with the midcortical glomeruli, while that of poor staining of the thin limb with PAS superficial glomeruli it was about 4.6 x 1011 (Fig. 13). The ascending limb of loop of (Table 6). Henle appears larger in size than that of the The proximal convoluted tubules were descending limb and is enclosing a wider seen between the superficial glomeruli and lumen. The epithelial cells lining of the renal capsule. The average diameter of ascending limb are generally of the low proximal convoluted tubules was about 20.7 type but not as flattened as those of the ± 2.8 µ. They appeared to be mainly the descending one with distinct boundaries principle structure seen between the (Fig. 14). They have a homogenous superficial glomeruli and the renal capsule eosinophilic cytoplasm. Their nuclei are (Fig. 10). The lumen of proximal spherical, located peripherally and deeply convoluted tubule is the widest of any basophilic with distinct nucleoli. The nuclei portion of the nephron. The internal lining being darker than those of descending limb is formed of cuboidal epithelial cells and with Mallory trichrome stain (Fig. 15). The sometimes it appeared as pyramidal shaped diameter of descending limb was measured and resting on the basement membrane. The about 15.5 ± 4.09 µ, while ascending limb boundaries of these cells were almost was 21.5± 1.0µ. indistinct and their ground cytoplasm was The distal convoluted tubules were the markedly eosinophilic and coarsly granular. second tubules of the cortex. The epithelial They have centrally located nuclei which lining was of cuboidal type enclosing a are large, spherical and rounded by darkly rather extensive lumen. The ground stained nuclear membranes and each one cytoplasm of the distal tubule was clearly posse a peripherally located nucleolus. One less eosinophilic than that of the proximal of the characteristic features of the proximal tubules. They have darkly basophilic convoluted tubule is the presence of a rounded nuclei placed in the centers of the striated brush border of the free surface of cells or a little near to the lumen (Fig. 15). its lining cells, which were lacking in any The part of the distal convoluted tubule in other part of the nephron. This border was contact with the glomerular root (the site of distinctly eosinophilic and PAS positive entrance of the efferent arterioles) has a such as the basement membrane of the rather modified appearance than the rest of tubules (Fig. 11). The lumen of the tubules these tubules. This region is identified as was quite narrow in some sections and the macula densa that had elongated lining rather wide in other depending on the cells closely packed with faintly stained direction of sectioning. cytoplasm. The diameter of distal The loop of Henle may be short, or convoluted tubules was about 21.1±5.9µ long depending on the position of its renal The collecting tubule consists of corpuscle. It is differentiated into thin epithelium that was quite different from descending limb which extendes to the other parts of the nephron. The epithelium inner medulla and thick ascending limb of the collecting tubule in the outer medulla which extended only in the outer medulla. was of cuboidal one with rounded nuclei of The thin descending limb had a distinct moderate size and slightly basophilic rounded lumen. It could be clearly cytoplasm. The collecting ducts were of distinguished from the other parts of the considerable length, this was due to the nephron on the bases of its low lining length of renal papilla. In the upper part of

592 Anatomical, Histological And Histochemical Studies On……..

the inner medulla, the epithelium in the last 4.3x1011 and 2.04x1011 respectively (Table part of the renal papilla lined the collecting 6). The diameter of proximal convoluted tubule becomes high cylindrical with large tubules measures about 27.7 ± 4.6 µ, which oval nuclei basally located with granulated was greater than that in Psammomys apical cytoplasm (Fig. 16). The diameter of obesus, with rounded lumen (Table 5). The collecting tubule is measured 49.7 ± 7.4 µ. boundaries of cells were indistinct with In Allactaga tetradactyla, the round nuclei which were located centrally structure of the kidney is more or less and rest on basement membrane (Fig. 19). similar to that of Psammomy obesus. The The loop of Henle consists of kidney was enveloped by renal capsule ascending and descending limb of loop of formed of connective tissue of eosinophilic Henle, the descending limb of loop of nature in Hx & E stain (Fig. 17). The renal Henle extends in the outer and inner capsule is thinner than that in Psammomys medulla. It has rounded lumen with obesus and the number of glomeruli in cuboidal cells and round nuclei. The longitudinal section was about 315 which diameter of these cells was recorded 18.9 ± was fewer than that in Psammomys obesus. 3.3 µ. It is thinner than that in Psammomys The number of glomeruli in the superficial obesus and change from cuboidal to region was recorded 133 glomeruli flattened cells (Fig. 20). The thick (42.2%), while in midcortical was 117 ascending ones have wider lumen than the (37.1%) and 65 (20.6%) in juxtamedullary descending one. The epithelium lining is (Table 4). The juxtamedullay glomeruli was high cuboidal cells greater than that found recorded approximately 1.9 and 1.8 times in the descending one (Fig. 21) and their greater in average diameter than the diameter measures 20.3 ± 0.8 µ. superficial and midcortical glomeruli The distal convoluted tubules were respectively (Figs. 18-19). lined by low columnar cells with round and The average glomerular volume of large nuclei. These cells rest on basement each zone in transverse sections of kidney membrane. The diameter of this tubule was was smaller than the glomerular volume of about 25.4 ± 4.6 µ. The ground cytoplasm each zone in kidney of Psammomys obesus. was stained red with Hx &E stain. The The glomerular blood volume in superficial collecting tubule as in Psammomys obesus was about 1.23x109 µ3 while in midcortical consists of different types of epithelial cells, and juxtamedullary was recorded the first which were in the outer medulla is 3.68x109µ3 and 31.5x109µ3 respectively cubical with round nuclei (Fig. 21). In the (Table 6). The glomerular volume of the tip of papillae, the epithelium is high juxtamedullary was approximately 25.6 and cylindrical in shape with large oval nuclei 8.5 times greater in average glomerular located centrally (Fig. 22). The diameter of volume of superficial and midcortical collecting tubule is about 58.2 ± 15.8µ. glomeruli respectively. The relative The vascular bundles were found glomerular blood volume of each zone of beside the descending limbs of loop of kidney was found to be lesser than that of Henle as in Psammomys obesus. They were Psammomys obesus. In superficial composed of venous and arterial vasa recta glomeruli, the relative glomerular blood and can be distinguished from the volume was equal to 1.63x1011 and in descending limb of loop of Henle by being midcortical and juxtamedullary was about strongly PAS positive (Fig. 23).

Table (1): Gross morphological measurements of rodent kidney

Kidney Mean Thickness( mm/g ) No. of Mean body weight Species kidney animals weight(g) /body Outer Inner weight( g) Cortex weightx103 medulla medulla Psammomys obesus 10 133.6±29.1 0.93±0.20 0.83x10-2 3.3 1.5 6.8 Allactaga tetradactyla 10 48.3±9.01 0.29±0.06 0.6x10-2 1.8 1.9 3.4

593 Boshra A. El- Salkh et al

Table (2): Measurements of dimensions of the kidneys of two rodent species.

Thickness (mm) Medulla Inner medulla

cortex length in % of Species Outer Renal cortex Inner medulla ratio medulla medulla Psammomys obesus 1.20 1.12 6.16 5.59 79.6 Allactaga tetradacty 0.82 0.94 4.9 2.9 64.1

Table (3): Statestical data of measurements of hepatic cells of Psammomys obesus and Allactaga tetradactyla

Nucleocyto No. of Mitotic Mitotic Vol. of Vol. of Vol. of plasmic cells cell index cells nucleus Cytoplasm index Average 6.556 4.489 68.277 41.703 13.934 27.768 56.368 Psammomys obesus SD 1.391 1.272 10.227 11.105 3.232 10.845 20.687

Average 7.273 3.409 45.844 31.740 12.925 17.759 75.335 Allactaga tetradactyla SD 1.897 1.896 19.214 4.902 1.400 5.231 31.250

Table (4): The glomerular number and percentages for three cortical zones of the kidneys of Psammomys obesus and Allactaga tetradactyla

Number of Superficial Midcortical Juxtamedullary Species glomeruli Number % Number % Number % Psammomys obesus 670 267 39.8 282 42 121 18 Allactaga etradactyla 315 133 42.2 117 37.1 65 20.6

Table (5): Numbers and diameter of glomeruli for three cortical zones of Psammomys obesus and Allactaga tetradactyla

No. of glomeruli Diameter of glomeruli Total number Species of glomeruli Cortex Midcortical Juxtamedullary Cortex Midcortical Juxtamedullary Psammomy 670 267 282 121 48.8±5.3 42.8±9.9 67.1±8.01 s obesus Allactaga 315 133 117 65 37.2±8.02 41.1±7.08 48.2±9.3 tetradactyla

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Table (6): The glomerular blood volume and relative glomerular blood volume for three cortical zones of the kidney of two rodent species

Superficial Midcortical Juxtamedullary Relative Relative Relative Glomerular Glomerular Glomerular Species glomerular glomerular glomerular blood blood blood blood blood blood volume volume volume volume volume volume Psammomys 1.72X109µ3 4.6X1011 7.6X109µ3 2.16X1012 40.8X109µ3 2.6X1012 obesus Allactaga 1.23X109µ3 1.63X1011 3.68X109µ3 4.3X1011 31.5X109µ3 2.04X1012 tetradactyla

Fig. (1): Photomicrograph of S. of the liver Fig. (2): Photomicrograph of S. of the liver of Psammomys besus. (Hx & E stain X 100) of Psammomys obesus (Hx & E stain X 400)

Fig. (3): Photomicrograph of S. of the liver Fig.(4): Photomicrograph of S. of the liver of of Psammomys obesus. (Hx & E stain X 400) Allactaga tetradactyla (AB- PAS stain X 400)

595 Boshra A. El- Salkh et al

Fig. (5): Photomicrograph of S. of the liver of Fig. (6): Photomicrograph of S. of the liver Allactaga tetradactyla of Allactaga tetradactyla

(Mallory trichrome stain X 100) (Mallory trichrome stain X 400)

Fig. (7): Photomicrograph of S. of the liver of Fig. (8): Photomicrograph of a L.S of the kidney Allactaga tetradactyla. (Hx &E stain X 400) of Psammomys obesus (Hx & E stain X100)

Fig. (9): Photomicrograph of a L.S of the kidney Fig. (10): Photomicrograph of a L.S of the kidney of Psammomys obesus (Hx & E stain X100) of Psammomys obesus (Hx & E stain X400) 596 Anatomical, Histological And Histochemical Studies On……..

Fig. (11): Photomicrograph of a L.S of the kidney Fig. (12): Photomicrograph of a L.S of the kidney of Psammomys obesus (AB- PAS stain X400) of Psammomys obesus (Hx & E stain X100)

Fig. (13): Photomicrograph of a L.S of the kidney of Fig. (14): Photomicrograph of a L.S of the kidney Psammomys obesus. (AB- PAS stain X400) of Psammomys obesus (Hx & E stain X400)

Fig. (15): Photomicrograph of a L.S of the kidney Fig. (16): Photomicrograph of a L.S of the kidney of Psammomys obesus of Psammomys obesus. (Hx & E stain X 400) (Mallory trichrome stain X100)

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Boshra A. El- Salkh et al

Fig. (17): Photomicrograph of a L.S of the kidney Fig. (18): Photomicrograph of a L.S of the kidney of Allactaga tetradactyla of Allactaga tetradactyla (Mallory trichrome stain X 400) (Mallory trichrome stain X 400)

Fig. (19): Photomicrograph of a L.S of the kidney Fig. (20): Photomicrograph of a L.S of the kidney of Allactaga tetradactyla. of Allactaga tetradactyla (Hx & E stain X 100) (Mallory trichrome stain X 400)

Fig. (22): Photomicrograph of a L.S of the kidney Fig. (21): Photomicrograph of a L.S of the kidney of Allactaga tetradactyla. of Allactaga tetradactyla (Hx & E stain X 400) (Mallory trichrome stain X 100) 598 Anatomical, Histological And Histochemical Studies On……..

Fig. (23): Photomicrograph of a L.S of the kidney of Allactaga tetradactyla (AB – PAS stain X 400) List of abbreviations: AL = ascending limb of loop of Henle; Hc = hepatic cell; Bs = blood sinusoid; Jx = juxtamedullary glomeruli; Ct = collecting tubules; Kf = kupffer cell; Cv = central vein; Mc = mucous cell. Cx = cortex; Mg = midcortical glomeruli; DL= descending limp of loop of Henle; Px = proximal convoluted tubules; Dx= distal convoluted tubules. Sg = superficial glomeruli; gc = goblet cell. Vb = vascular bundle;

Discussion

The present study comprises two the two investigated species, the liver was a types of rodent species, one of them was compund tubular gland covered by thin called fat sand rat Psammomys obesus, it layer of peritoneal epithelium formed of lives in the coastal and presaharan region, flattened cells resting on a thin basement frequently diurnal and feeds on halophytic membrane (Leeson et al., 1988). Each lobe plants (Zaime and Gauter, 1989). The was subdivided by connective tissue into second rodent was called four-toed jerboa polyhedral lobules and interlobular Allactaga tetradactyla. It was found in salt connective tissue restricted to the portal marshes and clay desert areas of coastal canal at the angles of the lobules. This plains. It was a nocturnal rodent and feeds confirms the findings of Basuony (1993). on seeds and succulent plants especially In Psammomys obesus, the hepatic with milky juices. It did not drink water at lobule was prismatic in shape with a central all, but lives on metabolic water produced vein forming its central axis. It was built up by the chemical breakdown of food of columns of hepatic cells, hepatocytes, (MacDonald, 1984). which radially arranged from the central The liver of the two investigated vein to the periphery of the lobule. The rodents is the largest gland in the body, hepatocytes were polygonal in shape; each located interiorly in the abdominal cavity cell possesses a distinct limiting membrane. just behind the diaphragm. It consists of Nuclei of hepatocytes were spherical or five lobes. This description was similar to ovoid with a regular surface. Occasionally those described for Mustela nivalis as binucleated cells were present. More or less mammalian species (El-Naggar, 1989). In similar observations were recorded by El-

599 Boshra A. El- Salkh et al

Naggar (1989) on the liver of Mustela The glomerular constituents include nivalis. In Allactaga tetradactyla, the podocytes, capillary, endothelial cells and lobulation of liver was less distinct than that connective tissue which were PAS positive. in Psammomys obsus. The mitotic index in A more or less similar observations had Allactaga tetradactyla was graeter than that been described in the kidney of rabbit by in Psammomys obesus, this observation Foster and Riad (1963) and of desert gerbil may be due to the increase the activity of Meriones crassus by Safer et al. (1990) and Allactaga tetradactyla. The liver gave PAS Abd-Elgawwad (1999). The variation positive reaction which indicates the between superficial, midcortical and secretion of both acid and neutral juxtamedullary glomeruli was the first mucosubstances. This result was in adaptation which had been observed in the agreement with Basuony (1993). kidney of desert rodent (Munkacsi and The urinary system of rodents was Palkovits, 1965 and Basuony, 1993). This composed of two kidneys, ureter, urinary variation in size leads one to suspect that bladder and urethera. This structure was the glomerular filteration surface would be similar in all mammals (Young, 1975). The much greater in the large juxtamedullary paired kidneys of the two investigated population of glomeruli, this could lead to rodents were bean-shaped and dark red preferential filtration in these nephrons and bodies located in the dorsal wall of the because they have long loops many results abdominal cavity. The general histological indicated maximal concentrating capacity. structure of the kidney displays a capsule, According to the previous observations, the outer cortex and inner medulla. kidney in Psammomys obesus had greater The kidney was enclosed in a thin filteration capacity than that found in fibroconnective tissue capsule, this was in Allactaga tetradactyla. This finding agrees agreement with Ali (1978). The cortex was with Hanssen (1961) who stated that, the composed of many rows of glomeruli. This glomerular filtration rate of the was maybe due to the higher thickness of juxtamedullary nephron is approximately the cortex, a similar observation had been eight times that of nephron from the outer described in Meriones libycus kidneys by cortex and the glomerular shape in the two Basuony (1993). The thickness of cortex in species was spherical (Munkacsi and Psammomys obesus is 1.32 mm, however, Palkovits, 1965 and Basuony, 1993). The in Allactaga tetradactyla measured about variation in number of glomeruli in the 0.82 mm. In the kidney of Psammomys kidney does not provide direct influence on obesus, there was a great variation in size the ability to produce concentrated urine. between glomeruli. The juxtamedullary This finding was in agreement with Abdalla glomeruli were approximately 1.5 and 1.8 and Abdalla (1979). times greater in average diameter than The second adaptation of desert midcortical and superficial glomeruli rodent was an increased elongation of the respectively. This lead to preferential inner medullary portion of the kidney of filtration in these nephrons and because Psammomys obesus when compared to that they have long loops, and this may result in found in Allactaga tetradactyla, this result maximal concentrating capacity. Similar agree with the gross adaptation of desert observations were recorded by Hanssen species especially rodents (Basuony 1993). (1961) and Basuony (1997). On the other On the other hand, they mentioned that the hand Allactaga tetradactyla juxtamedullary relative thickness of the medulla was glomeruli were approximately 1.9 and 1.8 related to their habit of the animal. The times greater in average diameter than the lengthening of the papillae was associated superficial and midcortical glomeruli with the lengthening of the collecting ducts respectively. Munkacsi and Palkovits and therfore results in an increased area for (1965) mentioned that the juxtamedullary water recovery through passive back glomeruli were 101% bigger than the diffution under the influence of antidiuretic cortical ones in J. jaculus (desert animal), hormone (Schimdt-Nielsen and O’Dell, 169% in Galago senegalensis (semidesert 1961; Berliner and Bennet, 1967; March animal) and 28% in Rattus norvigicus and Segel, 1971). Similar results were (water requiring animal). obtained in the present investigation. The

600 Anatomical, Histological And Histochemical Studies On…….. lengths of papillae were found to be greater References in Psammomys obesus than that recorded in Allactaga tetradactyla. 1. Abdalla M A and Abdalla O (1979): The average diameter of both Morphometric observations on the kidney proximal convoluted tubules and distal of the Camel, Camelus dromedarius. J. convoluted tubules in Psammomys obesus Anat., 129: 45-50. was less than that in Allactaga tetradactyla. 2. Abd-Elgawwad H A (1999): Comparative The internal lining was formed of cuboidal anatomical studies on some rodents and epithelial cells with indistinct boundaries their correlation with ecosystem. M. Sc. and their ground cytoplasm was Thesis, Al-Azhar University, Cairo for eosinophilic and coarsely granular while Girls. 3. Ali N H (1978): Comparative histological their central nuclei were basophilic. Neutral and histochemical studies on the kidney of mucosubstance was also investigated in the vertebrates. M.Sc. Thesis, Zool. Dep. Fac. striated brush border which gave PAS Sci. Ain Shams Univ. Cairo, Egypt. positive reaction. Vasa recta found in both 4. Altaschuler E M; Nagla R B; Braun E J; species and this was related directly to urine Linstedt S L and Krutzsch P H (1979): concentrating ability (Munkacsi and Morphological study of the desert Palkovits, 1977). The thin loop can be heteromyid kidney with emphasis on the distinguished from the arterial vasa recta by genus perognathus. Anat. Rec., 194: 461 – their bundles. PAS reaction allows an easier 468 differentiats due to the strong affinity of the 5. Basuony M I (1993): Habitat partitioning on anatomical basis among rodents of a basal lamina of arterial vasa recta as desert ecosystem. Ph.D. Thesis, Al-Azhar compared with poor stainning in the loops. University, Cairo. The vasa recta were considered to 6. Basuony M I (1997): Ecological variability participate in the countercurrent system and kidney structure of eight desert rodents. thus preventing the blood flow to the Egypt. J. Histol., 20 (2): 417– 434 medulla from washing away the 7. Basuony M I; Salem M Mand Younis M concentration gradient as indicated by I (2009): Kidney variability in two foxes in Berliner and Bennett (1967), Munkacsi and Egypt. Al-Azhar Bull. Sci. (in press). Palkovits (1977), Mona et al. (2007) and 8. Berliner R W and Bennett C H (1967): Hajime et al. (2008). The medulla cortex Concentration of the urine in the mammalian kidney. Am. J. Med., 42: 777- 789. ratio was recorded higher in Allactaga 9. Degan A A (1993): Energy requirements of tetradactyla (2.9%) than in Psammomys the fat sand rat (Psammomys obesus) when obesus (2.5%). In both species, the consuming the salt bush, Atriplex halimus: epithelium at the middle of the outer zone a review. J. Basic Clin. Physiol. of papilla changes from cuboidal to Pharmacol., 4 (1-2): 13-28 flattened cells. At a certain zone in the 10. EL-Banhawy M A; Demian E S; Shalaby papilla approximtely at the limit between A A and Roshdy M A (1972): Text Book the middle and distal third of the papilla, of Zoology. Dar Al-Maaref, 1119 Cornishe the epithelium of flattened cells becomes Enile, Cairo, Egypt. again cuboidal. This result was also 11. EL-Naggar E R (1989): Studies on the Weasel Mustela nivalis subpalmate observed in kangaroo rat by Vimtrup and M.Sc.Thesis Dept. Zool. Fac. Sci. Tanta Schmidt-Nielsen (1952) and in cricetid University, Egypt. rodents by Khalil and Tawfic (1963) and 12. Foster C l and Riad Z M (1963): Some Basuony (1993). These finding support the staining properties of the glomerular current physiological view that hypertonic constituents in normal rabbits. J. Anat., 97: urine was formed by active water 403-407. reabsorption in the distal and collecting 13. Hajime F; Hiroshi N; Koji W; ducts. The high efficiency of the kidney and Bernadene A and Ashley R. (2008): its role in the conservation of water depends Acute, subchronic and genotoxicity on the previous observations (Khalil and conducted with Oligonol, an oligomerized polyphynol formulated from lychee and Tawfic, 1963).

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green tea extracts. J. Food and Chem. Toxi., concentrating capacity. Acta Anat., 98: (46) 3553-3562. 456–458. 14. Hanssen D E (1961): The frequency of 28. Novikoff A B and Essner E (1960): The temporarily inactive glomeruli in mice liver cell: some new approaches to its under physiologic condition. Acta Pathol. study. Amer. J. Med., 29: 102–131. Microbiol. Scan., 53: 253–259. 29. Nowak R M (1991): Mammals of the 15. Happold D C D (1984): Small Mammals World. 5th edition. Jhons Hopkins in Sahara Desert: 251–275. Cloudsley– University press and Baltimore Thompson, J. L. (ed.,) pergamon press, 30. Osborn D J and Helmy I (980): The Oxford, London. contemporary land mammals of Egypt 16. Hendrickson R (1983): More Cunning (including Sinai), Fieldiana (Zool.) 5: 1-59 Than Man and Men. New York, Stein and 31. Palkovits M and Zolani B (1963): Day publishers. Quantitative histologic method zur 17. Hickman P C; Roberts S L and Hickman statistischen untersuchung des volumes der M F (1984): Integrated Principles of inerenglomeruli deren anteil an der nieren- Zoolgy. 7th Edition Times Mirror, Mosby rinde–3 Wiss. Mikroscopie, 65: 342–361. college publishering st. Lours Tornto Santa 32. Pearse A G E (1968): Histochemistry Clara. Canada. Theoretical and Applied. Vol. 1, Churchill 18. Kaissling B; Rouffignac C D; Barrett J Livingstone Publ. London. M and Krz W (1975): The structural 33. Purohit K G and Ghosh P K (1963): organisation of the kidney of the desert Histological and histochemical studies of rodent, Psammomys obesus. Anat. Embry., tissues of two desert rodents. Meriones 148: 121–143. hurrianae and Tetra Indica. Ann. Arid 19. Khalil F and Tawfic J (1963): Some zone, 2: 26-34. observations on the kidney of the desert J. 34. Safer A M; Al-Ajami N and Bou-Resli M Jaculus and G. gerbillus and their possible N (1990): Presence of vesicular bodies and bearing in the water economy of these thick basal laminae in the nephron of the animals. J. Exp. Zool., 154: 259-271. desert gerbil, Meriones crassus. Acta Anat., 20. Leeson T S; Leeson C R and Paparo AA 137: 261–271. (1988): Text Atlas of Histology. W. B. 35. Schmidt-Nielsen K and O’Dell R (1961): Sounders Co., USA. Structure and concentrating mechanism in 21. MacDonald D (1984): Encyclopedia of the mammalian kidneys. Amer. J. Physiol., Mammals Facts on File publications, New 200: 1119-1124. York 36. Vimtrup B and Schmidt–Nielsen B 22. March D J and Segel L A (1971): (1952): The histology of the kidney of Analysis of countercurrent diffusion kangaroo rats. Anat. Rec., 114: 515–528. exchange in blood vessels of the renal 37. Wilson S and Reeder A (2005): Mammal medulla. Am. J. Physiol., 221: 817-828 species of the world. Jhons Hopkins 23. Marquie G; Duhault J and Jactor B University press and Baltimore (1984): Diabetes mellitus in Sand Rat 38. Young Z J (1975): The Life of Mammals; (Psammomys obesus). Metabolic pattern Their anatomy and Physiology, second during development of the diabetic edition, claredom press Oxford. syndrome. Diabetes, 33 (5): 438–443 39. Younis M M (2008): Environmental 24. Mc Manus JPA (1946): Histological impacts of different habitats on kidney demonstration of mucin after periodic acid. structure and function of some mammals. Nature (London), 158(4006): 202. M.Sc. Thesis, Al-Azhar University, Cairo. 25. Mona A H Y; Sabah G E and Aly B O 40. Zaime A and Guater J Y (1989): (2007): Diazinon toxicity affects Comparison des regions alimentaires de histophysiological and biochemical trois especes sympatriques de gerbillidae en parameters in rabbits. Exper. and Toxi. mileu Saharian, au Maroc. Rev. Ecol., 44: Patho., (59) 215-225. 153–163. 26. Munkacsi I and Palkovits M (1965): 41. Zaki Z T (1993): Histological and functi- Volumetric analysis of glomerular size in onal relationship of the kidney of hedge- kidneys of mammals living in desert, hogs. Egypt. J. Histol., 16 (2): 451 – 466. semidesert or water– rich environment in 42. Zaki Z T; Basuony M I and Ibrahim I G the Suda. Circ. Res., 17: 303–311. (1994): Ecological significance of 27. Munkacsi I and Palkovits M (1977): anatomical and histological structure of Measurments on the kidney and vasa recta some mammalian kidney. Egypt. J. Histol., of various mammals in relation to urine 17(1): 193–208.

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دراسبت تشريحية ، نسيجية وكيميب نسيجية علً بعط أعضبء القىارض الصحراوية فً بيئبتهب الصحراوية المصرية

بشري عبد العسيس السلخ*، زكً تىفيق زكً**، محمد ابراهيم بسيىنً** و هنبء خضر* قسى ػهى انحيىاٌ كهيخ انؼهىو جبيؼخ األصهش *-فشع انجُبد **- فشع انجُيٍ

يزضًٍ هزا انجحش دساسبد ػهً َىػيٍ يٍ انقىاسض انصحشاويخ يؼشفبٌ ثبسى فأس انشيم انسًيٍ وانجشثىع سثبػً األصبثغ وقذ اشزًهذ انذساسخ ػهً دساسبد رششيحيخ و َسيجيخ نكم يٍ انكجذ وانكهً, وإلجشاء رهك انذساسخ رى رجًيغ انؼيُبد يٍ ثيئبرهب انطجيؼيخ و شًهذ انصحشاء انششقيخ ،انصحشاء انغشثيخ، صحشاء سيُبء ثىاسطخ يصبئذ خبصخ و رى َقههى انً انؼًًم ورخذيشهى ورششيحهى إلجشاء انذساسخ وكبَذ انُزيجخ كبنزبنً: أو ال : انكجذ يؼزجش أكجش غذح فً انجسى وهى يقغ خهف انحجبة انحبجض فً انجضء انؼهىي يٍ انجطٍ. يزكىٌ انكجذ يٍ خًسخ فصىص يُفصهخ. يٍ انُبحيخ انُسيجيخ هى ػجبسح ػٍ غذح أَجىثيخ يشكجخ يغطبح ثطجقخ سقيقخ يٍ انطالئيخ انجشيزىَيخ رزكىٌ يٍ فصىص كجذيخ وأوسدح يشكضيخ ورزكىٌ هزِ انفصىص انكجذيخ يٍ خاليب كجذيخ. وقذ وجذ ثبنجحش أٌ يؼبيم األَقسبو انًيزىصي فً فأس انشيم انسًيٍ أقم ثكضيش يٍ انجشثىع سثبػً األصبثغ ورنك يشجغ انً صيبدح َشبط انجشثىع سثبػً األصبثغ. صبَيب ا: رزشكت انكهيخ يٍ صالصخ أجضاء هً انًحفظخ، انقششح وانهت. سًك انقششح فً فأس انشيم انسًيٍ أكجش يٍ انجشثىع سثبػً األصبثغ أيب انهت فيُقسى انً جضءيٍ، جضء خبسجً و جضء داخهً وقذ كبٌ طىل انهت انخبسجً وانذاخهً فً فأس انشيم انسًيٍ أكجش يُهب فً انجشثىع سثبػً األصبثغ. أيب يٍ انُبحيخ انهسزىنىجيخ فبنكهيخ ػجبسح ػٍ غذح أَجىثيخ يشكجخ رزشكت يٍ ػذد كجيش يٍ األَيجيجبد انجىنيخ، وكم أَيجيجخ ثىنيخ رزكىٌ يٍ وحذاد َفشيذيخ و أَيجيجبد يجؼًخ. كم وحذح َفشيذح رزكىٌ يٍ كشيبد يهجيجً انزً رشزًم ػهً يحفظخ ثىيبٌ وانكجخ. قسًذ انقششح فً كال انُىػيٍ انً صالس يُبطق، سطحيخ ووسطيخ ويجبوسح نهت. رى إحصبء ػذد انكجبد فً كم قطبع طىنً يٍ انكهيخ نكال انُىػيٍ ،و وجذ أٌ ػذد انكجبد فً فأس انشيم انسًيٍ أكجش يٍ رهك انًىجىدح فً انجشثىع سثبػً األصبثغ كًب أوضحذ انذساسخ انهسزىنىجيخ أٌ قطش انكجبد وأحجبيهب وكزنك انحجى انُسجً نهذو فً انكجبد فً فأس انشيم انسًيٍ أكجش يُهب فً انجشثىع سثبػً األصبثغ. و قذ أصجزذ انذساسبد وكزنك انقيبسبد أٌ فأس انشيم انسًيٍ رو يقذسح ػبنيخ ػهً رشكيض انجىل أكضش يٍ انجشثىع سثبػً األصبثغ.

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