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Preliminary Anatomical and Histological Study of Lacrimal

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Preliminary Anatomical and Histological Study of Lacrimal ary Scien in ce r te & e T V e f c h o Abbasi et al., J Veterinar Sci Technolo 2014, 5:1 n l Journal of Veterinary Science & o a l n o r DOI: 10.4172/2157-7579.1000154 g u y o J ISSN: 2157-7579 Technology Research Article Open Access Preliminary Anatomical and Histological Study of Lacrimal Gland in Lori Sheep Mohsen Abbasi1, Hamid Karimi2* and Ahmad Gharzi3 1Department of Basic Sciences, Faculty of Veterinary Medicine, University of Lorestan, Iran 2Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tabriz, Iran 3Department of Biology, Faculty of Basic Sciences, University of Lorestan, Iran Abstract The lacrimal gland is an important part of lacrimal apparatus that plays an essential role in eye health. In this research, anatomical and histological structures of lacrimal glands of Lori sheep were evaluated. For this purpose, thirty healthy and mature Lori sheep were selected in slaughterhouse and then lacrimal glands removed. After anatomical and biometrical evaluation, lacrimal glands were fixed and processed for histological sectioning and then sections stained with H&E, Alcian blue and Periodic acid Schiff methods. The results showed that in this species the lacrimal gland lies in dorso-lateral aspect of orbit on the eyeball. The lacrimal gland is surrounded with a connective tissue containing adipose tissue. The gland shows an irregular-rounded to oval shape and pale brown in color. The mean weight, length, width and thickness of the gland were 1.48 ± 0.3 gr, 26.98 ± 0.37 mm, 20.11 ± 0.31 mm and 3.58 ± 0.7 mm, respectively. Histological examinations revealed that the lacrimal gland is lobulated and cells of parenchyme are mixed including serous and mucous cells. Intralobular, interlobular and excretion ducts of the gland are lined with cuboidal, stratified cuboidal and pseudo stratified columnar epithelium, correspondingly. In some ducts goblet cells are present among epithelial cells. Keywords: Lacrimal gland; Lori sheep; Histology; Anatomy make sure the samples are really healthy the samples once again were carefully examined in the laboratory. Eyeballs were removed from Introduction orbits cutting off the skin and surrounding tissues. Extensive care was The eye is a complex and highly developed organ which collects employed to avoid any damage to lacrimal glands. Then the glands light from the surrounding environment, regulates its intensity through were measured biometrically. During the biometric measurements, a diaphragm, focuses it through an adjustable lens to form an image the weight and dimensions of the gland including the gland’s length on retina where this image is converted into a set of electrical signals (the medio-lateral edge), width (the rostro-caudal edge) and thickness transmitted to the brain. The eyes are protected in the skull by a bony (the dorso-ventral edge) were recorded. Moreover, the thickness of the box called the eye socket (orbit). The wall of this eyeball consists of three gland’s medial part was measured. The measuring of weight and length layers which have different tasks in the anterior and posterior halves was made by a scale and Vernire caliper with an accuracy of 0.01 g and of the organ [1]. One of accessory structures of the eye is the lacrimal 0.01 mm, respectively. apparatus which located superiorly and laterally to each eyeball. Each Following the measurements, a cannula with one-millimeter lacrimal apparatus consists of the lacrimal gland, canalicule, lacrimal diameter was inserted into the lacrimal punctum and lacrimal sac. By sac and naso lacrimal duct [2]. The lacrimal glands are responsible for flushing water into this punctum, the exit opening of the naso lacrimal production of tears which flow over the conjunctiva [1]. The lacrimal duct was distinguished. Moreover, length of nasolacrimal duct was gland is responsible for production and secretion of tears which clean measured by inserting the cannula all the way through the duct. All and nourish the cornea and help to maintain its health. In many species, data provided from these measurements were then analyzed by the the main fraction of tears is produced by lacrimal glands. In cattle and germinal linear models procedure of SPSS software (version 11.5, SPSS wild buffalo, no difference is observed between left and right glands. Inc, Chicago, USA). Means were separated by Duncan’s Multiple range Moreover, in these animals no sexual dimorphism is evident in the case test and significance was accepted at p<0.05. Later the samples were of the lacrimal gland [3]. There are adequate researches documenting fixed with formalin saline and then processed for preparing histological the anatomy and histology of lacrimal glands in human and some other sections. Five to seven micrometer sections were cut using a rotary mammals. In all investigated species, the lacrimal gland has presented microtome and they were then stained by Hematoxylin and Eosin and more or less a similar histological structure and is a mixed gland Periodic Acid Schiff (PAS), Alcian Blue (pH 2.5) methods. consisting of tubulo-acinar units [4]. There is a lack of literature on the lacrimal gland in this breed of sheep, our research will contribute to the comparative anatomy and histology and help to understanding the *Corresponding author: Hamid Karimi, Department of Basic Sciences, Faculty structure of this gland. Moreover, many chemical components in the of Veterinary Medicine, University of Lorestan, Iran, Tel: +98 411 330 0819; E-mail: tear have been documented [5-9]. In current study, the anatomical and [email protected]; [email protected] histological structure of these glands Lori sheep is scrutinized. Received November 28, 2013; Accepted January 24, 2014; Published January 27, 2014 Materials and Methods Citation: Abbasi M, Karimi H, Gharzi A (2014) Preliminary Anatomical and In this study, 15 male and 15 female adult apparently healthy head Histological Study of Lacrimal Gland in Lori Sheep. J Veterinar Sci Technol 5: 154. doi:10.4172/2157-7579.1000154 (without any eye disease) of Lori sheep just after slaughter were selected in Khorramabad slaughterhouse. To dental condition, age of sheep Copyright: © 2014 Abbasi M, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted were over than one years. Lacrimal glands were removed. The healthy use, distribution, and reproduction in any medium, provided the original author and samples were identified according morphological characters [10]. To source are credited. J Veterinar Sci Technolo ISSN: 2157-7579 JVST, an open access journal Volume 5 • Issue 1 • 1000154 Citation: Abbasi M, Karimi H, Gharzi A (2014) Preliminary Anatomical and Histological Study of Lacrimal Gland in Lori Sheep. J Veterinar Sci Technol 5: 154. doi:10.4172/2157-7579.1000154 Page 2 of 4 Results In Lori sheep the lacrimal gland is pale brown in color and irregular oval to spherical in shape located on the dorsolateral surface of the eyeball. The gland displays a lobular appearance and is encompassed by a connective tissue through which in connects to the orbit (internal surface of the frontal bone) dorsally and to the eyeball ventrally (overlaps the rectus dorsalis muscle). Lacrimal gland is compressed between the orbit and the eyeball (Figure 1). As a result of this compression, the dorsal surface of the gland is convex while its ventral surface is concave. This difference in the shape of dorsal and ventral surfaces is clearly evident in fixed specimens. In some samples a part of the lacrimal gland is surrounded by an adipose tissue found around the eyeball. Biometric data relating to Lori sheep’s lacrimal gland have been summarized in Table 1. Figure 3: A micrograph displaying mucous acini in higher magnification. The The excretory duct of the lacrimal gland opens over conjunctiva components (red) of these acini show a high affinity to PAS.( PAS staining, on the internal surface of the upper lid. The lacrimal puncta of upper ×200). and lower lids are in the medial angle of eyes. The color of these puncta varies according to the color of skin sample. Lacrimal canals start from upper and lower lacrimal puncta and after merging together lead to the medial angle of the eye (Figure 2). Figure 4: A histological section showing mucous acini and goblet cells (purple) in the linning epithelium of interlobular ducts. (PAS staining, ×100). Figure 1: A photograph displaying situation of the lacrimal gland in a Lori The lacrimal sac is situated in the medial corner of the orbit (within sheep eye. The upper part of the eye has been dissected to expose the gland the lacrimal bone). A nasolacrimal duct extends from the sac to the (Lg) which is located on the orbit and in a dorsolateral situation to the eyeball. nostril. This duct shows a mean length of 12.57 cm and runs in a The surrounding connective tissue (Pt) and lateral (L) and medial (M) corners of the eye is observed. direct pathway through the maxillae. The minimum and maximum length of this duct in Lori sheep was 10.8 and 14.3 cm, respectively. The end of the nasolacrimal ducts opens into lateral surface of nasal Characters Minimum Maximum Mean ± SE cavity. This opening was on average 1.76 cm away from the nostril. Weight (gr) 0.90 2.54 1.48 ± 0.3 The minimum and maximum space between the exit opening of the Length (mm) 21.06 34.39 26.98 ± 0.37 nasolacrimal duct and the nostrils was measures to be 1.4 and 2.4 cm, Width (mm) 14.56 25.38 20.11 ± 0.31 correspondingly. The nasolacrimal opening is situated over the medial Thickness (mm) 2.33 5.20 3.58 ± 0.7 surface of the nasal alar fold.
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