Anatomical and histological structures of eye and lacrimal gland in Norduz and Morkaraman sheep

Authors: SEMİNE DALGA, SERAP İLHAN AKSU, KADİR ASLAN, TURGAY DEPREM, REŞİT UĞRAN

Abstract: The current study was conducted to determine the morphological, morphometric, and histological characteristics of bulbus oculi and lacrimal gland in sheep. For this purpose, 28 pairs (n = 7 males and n = 7 females) of bulbus oculi from Morkaraman and (n = 7 males and n = 7 females) Norduz sheep were analyzed. The bulbus oculi in the skulls were dissected from the orbit and removed. The morphometric data such as distance between endpoints of the dissected bulbus oculi in temporal, nasal, and dorsal directions, the length between endpoints of the pupil in dorsal and ventral directions, and as well as in temporal and nasal directions were measured with a digital caliper. For histological analyses, the eye tissues of Norduz and Morkaraman sheep were fixed in 10% formaldehyde solution. Then, the tissues were blocked by paraffin via passing them through the routine histological tissue follow-up solutions. Dissections in 6-μm thickness were made from the blocks. To evaluate the tissues histologically, tissue sections were stained with Crossmann's modified triple staining technique (triple staining). The mean values and standard deviations of the acquired data and the correlation coefficients among these characters were evaluated by the SPSS 22 program. The dorso-ventral diameter of bulbus oculi (BDV) was measured as an average of 25 ± 0.95 and 26.67 ± 3.19 mm in female and male Norduz sheep, respectively. Similarly, the BDV diameter in Morkaraman sheep was measured as 26.19 ± 1.04 mm in females and 26.41 ± 0.92 mm in males. As a result of analysis between genders in Norduz sheep, the BDV diameter, medio-lateral diameter of cornea (CML), dorso-ventral diameter of pupil (PDV), and dorso-ventral diameter of lens (LDVÇ) were identified statistically significant (p < 0.05). However, the results of the gender analysis in Morkaraman sheep demonstrated that none of the parameters were statistically significant (p > 0.05). The eye layers, the tunica fibrosa bulbi, tunica vasculosa bulbi, and tunica interna bulbi of both male and female Morkaraman and Norduz sheep were studied through the microscopic analysis. It was specified that both sheep species and both genders had a very wide tapetum fibrosum structure in the choroid of eye structures. It was also determined that the lacrimal gland had a seromucous characteristic and a tubuloacinar structure.

Keywords: Eye anatomy, histology, lacrimal gland, sheep

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