Paszta Wojciech, Goździewska-Harłajczuk Karolina, Klećkowska-Nawrot Joanna
Wroclaw Zoological Garden, Wróblewskiego 1/5, 51-618 Wrocław, Poland.
Department of Biostructure and Animal Physiology, Faculty of Veterinary Medicine, Wrocław University of Environmental and Life Sciences, Kożuchowska 1, 51-631 Wrocław, Poland.
Animals (Basel). 2022 Mar 22;12(7):801. doi: 10.3390/ani12070801.
In this study, we present first data concerning the morphological observations of the orbital region, eye tunics, upper and lower eyelids, superficial gland of the third eyelid with the third eyelid, and lacrimal gland in captive adult male Asiatic black bear. The following research methods were used in the work: the eyeball morphometry, the orbital region description, macroscopic description, morphometric and histological analysis of the eye tunics and selected the accessory organs of the eye (Fontana-Masson, hematoxylin & eosin (H&E), Methyl-green-pyronin Y (MGP Y), Movat pentachrome, and picro-Mallory trichrome) as well as histochemical examination (PAS, AB pH 1.0, AB pH 2.5, AB pH 2.5/PAS and HDI). The eyeball of the Asiatic black bear was a spherical shape, while the periorbita was funnel/conical-shaped and the eye socket was of the open type. The cornea was absent of the Bowman's membrane similar to all domestic dogs and some wild dogs. There were palisades of Vogt in the corneal limbus epithelium similar to the Canidae. Degenerative choroidal tapetum lucidum similar to ranch mink (Mustelidae) has been found. The pupil was big and round in shape. The ciliary muscle, dilatator and sphincter muscle were well developed, similar to the pinnipeds. The lens was biconvex round, similar to the Canidae. The retina was composed similarly to the diurnal terrestrial carnivores. In both eyelids were observed very well-developed tarsal glands, ciliary glands and sebaceous glands. The orbital zone in the eyelids was characterized by lymphoid follicles, diffuse lymphocytes and specialized high endothelial venules. In the anterior palpebral margin of the upper eyelid, soft and short eyelashes were observed, while in the lower eyelids they were absent. The third eyelid was T-shaped and composed of the hyaline tissue, and it contained CALT, similar to that in Canidae. The superficial gland of the third eyelid was a multilobar alveolar branched complex with seromucous nature, while the lacrimal gland was also a multilobar acinar branched complex gland, but producing a mucous-serous secretion. The results of our research indicate that the features of the anatomy of the eye and orbital region in Asiatic black bear are also typical of the Ursidae family. Moreover, a detailed analysis of the morphological eye region may be useful in comparative studies and veterinary diagnostics in this bear species.
在本研究中，我们首次呈现了圈养成年雄性亚洲黑熊眼眶区域、眼膜、上下眼睑、第三眼睑及其浅表腺体以及泪腺的形态学观察数据。本研究采用了以下研究方法：眼球形态测量、眼眶区域描述、宏观描述、眼膜及选定眼附属器官的形态测量和组织学分析（Fontana-Masson染色、苏木精-伊红染色（H&E）、甲基绿-派洛宁Y染色（MGP Y）、Movat五色染色和苦味酸-马洛里三色染色）以及组织化学检查（过碘酸希夫染色、pH 1.0阿利新蓝染色、pH 2.5阿利新蓝染色、pH 2.5阿利新蓝/过碘酸希夫染色和高密度脂蛋白免疫组化）。亚洲黑熊的眼球呈球形，眶周呈漏斗状/圆锥形，眼眶为开放式。与所有家犬和一些野生犬类相似，角膜无Bowman膜。角膜缘上皮有Vogt栅栏，与犬科动物相似。发现了与养殖水貂（鼬科）相似的退化性脉络膜明毯。瞳孔大且呈圆形。睫状肌、散瞳肌和括约肌发育良好，与鳍足类动物相似。晶状体为双凸圆形，与犬科动物相似。视网膜的组成与昼行性陆生食肉动物相似。在上下眼睑中均观察到非常发达的睑板腺、睫腺和皮脂腺。眼睑的眶区以淋巴滤泡、弥漫性淋巴细胞和特化的高内皮微静脉为特征。在上眼睑前缘观察到柔软且短的睫毛，而下眼睑则没有。第三眼睑呈T形，由透明组织组成，含有结膜相关淋巴组织（CALT），与犬科动物相似。第三眼睑的浅表腺体是一个多叶肺泡分支复合体，具有浆液性黏液性质，而泪腺也是一个多叶腺泡分支复合腺，但分泌黏液-浆液性分泌物。我们的研究结果表明，亚洲黑熊眼睛和眼眶区域的解剖特征也是熊科动物的典型特征。此外，对眼部形态区域的详细分析可能有助于该熊种的比较研究和兽医诊断。
