Microscopically Studies on the Liver of Acanthodactylus Boskianus Lizard
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Egypt. Acad. J. Biolog. Sci., 11(1): 94- 62 (2019) Egyptian Academic Journal of Biological Sciences D. Histology & Histochemistry 2090 – 0775 www.eajbsd.journals.ekb.eg Microscopically Studies on the Liver of Acanthodactylus boskianus lizard Allam A. M. Nafady 1 and Eatemad A. Awadalla*2 1-Department of Pathology, Faculty of Veterinary Medicine, Assiut University, Egypt 2-Department of Zoology Faculty of Science Aswan University, Aswan, 81528 Egypt. E. Mail.: [email protected] ARTICLE INFO ABSTRACT Article History The aim of this study was to investigate the histological and fine Received: 25/2/2019 structure of the liver of Acanthodactylus boskianus during the Accepted: 1/4//2019 hibernation period, using ten adult specimens captured from sandy _________________ Keywords: areas of Aswan Governorate, Egypt. Specimens of liver were fixed for Acanthodactylus light and transmission electron microscope to study the hepatic architecture during this period. In addition to haematoxylin and eosin boskianus, Liver, stain, the histochemical and special stains were used. The hepatocytes light and electron are arranged in hepatic plates. The radial arrangement of hepatic cords microscopy around the central vein is generally not apparent. The several-cell-thick plate type showed with multi-layered of hepatocytes separated by narrow tortuous capillaries networks, sinusoids that are localized in the space between hepatic plates. The hepatic cells of Acanthodactylus boskianus under light and T.E.M. are similar to those of other vertebrates (birds and mammals), except for the presence of melano- macrophages. INTRODUCTION The Reptilia class is a prominent part of all terrestrial assemblage, containing 9,084 species by the latest count (Uetz and Hallermann, 2010). Reptiles are represented by four orders: Crocodilia, Rhynchocephalia; Squamata and Testudinata. The Squamata order includes lizards, land animals with well-defined eating habits (Vitt et al., 2003). Reptiles are very important for t h e maintenance of ecosystems. For this reason, many papers have been published on their geographic and population distribution and ecological and behavioral aspects. However, few studies have been published on the morphological aspects of these animals. These factors are important for their correct classification and comparison against other phylogenetically related species and to establish their interaction with the biome where they live (Firmiano et al., 2011; Hamdi et al., 2014). The genus Acanthodactylus is commonly known as the fringe-fingered lizards and is the largest genus in the family Lacertidae with over 40 described species (Uetz, 2013). Members of this genus are small- to medium-sized, diurnal, terrestrial, and oviparous species that inhabit semi-arid to desert ecosystems from the Iberian Peninsula, through North Africa, to the Middle East and West India, Citation :Egypt. Acad. J. Biolog. Sci. ( D-Histology and histochemistry) Vol.11(1)pp94-62(2019) 50 Allam A. M. Nafady 1 and Eatemad A. Awadalla*2 including Cyprus and the Arabian morphology is a valuable source of Peninsula (Sindaco and Jeremcˇenko, information for clinicians. It is 2008).The latter three studies divided fundamental for the proper diagnosis the genus into species groups, a of reptile diseases. Schaffner division that is commonly used today ( Schaffner, 1998) analyzed the livers (Tamar, 2014). of reptiles in general, but few studies The Acanthodactylus boskianus have examined the liver of species group is a striking case of Acanthodactylus boskianus. Therefore, taxonomic uncertainty. Although it is a the purpose of this study was to small group of only three species, its characterize the liver of this species geographical range is the largest in microscopically during hibernation, to the genus. It includes shed light on the morphological aspects Acanthodactylus boskianus (Daudin, of this class of reptile. 1802), Acanthodactylus schreiberi MATERIALS AND METHODS (Boulenger, 1878) and Ten adult specimens (male and Acanthodactylus nilsoni (Rastegar- female) of Acanthodactylus boskianus Pouyani, 1998). Acanthodactylus lizard were collected in February boskianus is the most widespread 2018. They were captured from sandy species of its genus ranging through areas of Aswan Governorate and North Africa (Salvador, 1982). identified by Dr. Sherif Baha El Din, Acanthodactylus boskianus has been Environmental Consultant, Ecologist, divided into five subspecies: A. Ornithologist, Herpetologist, and boskianus boskianus (Daudin, 1802) President Nature Conservation Egypt. from the Nile delta and parts of Sinai, After capture, the specimens were A. boskianus asper (Audouin, 1827) taken to the Zoological Laboratory of from much of the distribution range Science Faculty, Aswan University, of the species, A. boskianus where they were anaesthetized and euphraticus (Boulenger, 1919) from dissected according to the Animal Care Iraq, A. boskianus khattensis from and Use Committee, University of Mauritania and A. boskianus Aswan. After lizards dissection the nigeriensis from Niger (Trape et al., liver specimens rapidly excised, and 2012). Animals in Aswan are A. b. immediately fixed for light and electron asper. microscopy. The liver has multiple and After fixation in neutral buffer complex functions. It is the site of formalin was completed, the numerous metabolic processes, because specimens were washed, dehydrated it receives all the material absorbed by in ascending grades of ethyl alcohol, the intestines, except for a certain cleared in methyl benzoate and finally quantity of lipids transported by the embedded in paraffin wax, the lymph nodes (Samuelson, 2007). The paraffin blocks were sectioned at a liver is one of the most important thickness of 5-6 µm. Then the organs in the organism, because it following stains were utilized: metabolizes stores, synthesizes and 1. Harris’s haematoxylin and eosin eliminates the substances absorbed. It (Harris, 1990). also produces bile, an exocrine 2. Masson`trichrome s t a i n ( Lillie, 1940) secretion of the hepatic cells, which for t h e collagenous fibers. plays a key role in the digestion and 3. Periodic acid Schiffʹs (PAS) technique for absorption of fats (Pough et al., 1999). general carbohydrates, Mc Manus (1946). Knowledge of reptiles’ liver Microscopically Studies on the Liver of Acanthodactylus boskianus lizard 51 Electron Microscopy: particles. Also, existence of a few For ultrastructural examination, pigmented cells termed melano- the samples processed examined and macrophages formed part of the lining photographed in E. microscopic Unit of the sinusoids, protruded into the in Assiut University. Small pieces of sinusoidal lumen; they were also liver were immediately immersed in located in the hepatic parenchyma (Fig. 4F1G in phosphate buffer (pH 7.2) 1a). fixation mixture for 3 hr at 4°C then The peripheries of a lobule can post-fixed in 1% OsO4 (Osmium be defined by portal areas of tetroxide) at 4°C for 2 hr. The connective tissue enclosing three main specimens were dehydrated in graded structures, a bile ductule, branches of series of ethanol and then embedded the hepatic portal vein, and a branch of in Epon-Araldite mixture in labeled the hepatic artery. The lumen of the beam capsules. LKB ultramicrotome portal vein appears enclosing a few was used to obtain ultrathin sections blood cells. The bile ductule has a layer (50 nm thick) which were picked of cuboidal epithelial cells (Fig. 1b). upon 200 mesh naked copper grids. Also, t h e examination of the Grids were double stained with uranyl Acanthodactylus boskianus liver showed acetate for ½ h and lead citrate for 20- that the liver is covered by a thin layer 30 min. Scoping the grids was achieved of connective tissue forming the by using TEM 100 CXII electron hepatic capsule (Fig.1c). This capsule microscope at 80 KV and photographed is common to all vertebrates and by CCD digital camera Model XR- 41. contributes to the division of the RESULTS parenchyma into structural units, called Light Microscopy: hepatic lobules. Also, the microscopic Light microscopy inspections of analysis revealed that a mild amount of the liver section of Acanthodactylus connective tissue stroma, principally boskianus lizard were illustrated in of collagenous fibers was detected figure (1). The liver is not as around the central vein as well as the distinctly organized into lobules as in sinusoidal walls (fig.1d). In addition, mammals. The functional and basic unit each portal area was surrounded by a of the lobules is the hepatocytes. The moderate amount of collagenous hepatocytes are arranged in several- network which was continuous with cell-thick plates or cords which are scanty interlobular collagenous fibers disposed of in such a way to exhibit (Fig. 1e). a net-like structure arise from a Inspection of the figure (1f) centrally located vein, the central vein showed that the hepatocytes contained to the lobular periphery. The radial a considerable amount of glycogen arrangement of hepatic cords around granules, appearing in the form of the central vein is generally not strongly PAS-reactive granules of apparent. The several-cell-thick plate of variable sizes, located mainly in the hepatocytes separated by narrow and ground cytoplasm. These granules short tortuous capillaries networks; clumped together into rather massive sinusoids which are lined with Kupffer patches condensed mainly at one pole cells and endothelial cells. The of the cell. hepatocytes have a homogenously fine Electrn Microscopy: granulated