Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Killianstrasse 5, 79106 Freiburg, Germany.
CEMT-Freiburg, Experimental Surgery, Hospital-Medical Center, Faculty of Medicine, University of Freiburg, Breisacher Str. 66, 79106 Freiburg, Germany.
Int J Mol Sci. 2023 Apr 19;24(8):7543. doi: 10.3390/ijms24087543.
The porcine ocular surface is used as a model of the human ocular surface; however, a detailed characterization of the porcine ocular surface has not been documented. This is due, in part, to the scarcity of antibodies produced specifically against the porcine ocular surface cell types or structures. We performed a histological and immunohistochemical investigation on frozen and formalin-fixed, paraffin-embedded ocular surface tissue from domestic pigs using a panel of 41 different antibodies related to epithelial progenitor/differentiation phenotypes, extracellular matrix and associated molecules, and various niche cell types. Our observations suggested that the Bowman's layer is not evident in the cornea; the deep invaginations of the limbal epithelium in the limbal zone are analogous to the limbal interpalisade crypts of human limbal tissue; and the presence of goblet cells in the bulbar conjunctiva. Immunohistochemistry analysis revealed that the epithelial progenitor markers cytokeratin (CK)15, CK14, p63α, and P-cadherin were expressed in both the limbal and conjunctival basal epithelium, whereas the basal cells of the limbal and conjunctival epithelium did not stain for CK3, CK12, E-cadherin, and CK13. Antibodies detecting marker proteins related to the extracellular matrix (collagen IV, Tenascin-C), cell-matrix adhesion (β-dystroglycan, integrin α3 and α6), mesenchymal cells (vimentin, CD90, CD44), neurons (neurofilament), immune cells (HLA-ABC; HLA-DR, CD1, CD4, CD14), vasculature (von Willebrand factor), and melanocytes (SRY-homeobox-10, human melanoma black-45, Tyrosinase) on the normal human ocular surface demonstrated similar immunoreactivity on the normal porcine ocular surface. Only a few antibodies (directed against N-cadherin, fibronectin, agrin, laminin α3 and α5, melan-A) appeared unreactive on porcine tissues. Our findings characterize the main immunohistochemical properties of the porcine ocular surface and provide a morphological and immunohistochemical basis useful to research using porcine models. Furthermore, the analyzed porcine ocular structures are similar to those of humans, confirming the potential usefulness of pig eyes to study ocular surface physiology and pathophysiology.
猪的眼表面被用作人眼表面的模型；然而，尚未详细描述猪眼表面。这部分是由于缺乏专门针对猪眼表面细胞类型或结构的抗体。我们使用一组 41 种不同的抗体，对来自家猪的冷冻和福尔马林固定、石蜡包埋的眼表面组织进行了组织学和免疫组织化学研究，这些抗体与上皮祖细胞/分化表型、细胞外基质和相关分子以及各种生态位细胞类型有关。我们的观察结果表明，Bowman 层在角膜中不明显；角膜缘区的缘上皮的深层内陷类似于人角膜缘组织的缘间栅栏隐窝；以及在球结膜中存在杯状细胞。免疫组织化学分析显示，上皮祖细胞标志物角蛋白 (CK)15、CK14、p63α 和 P-钙黏蛋白在角膜缘和结膜基底上皮中均有表达，而角膜缘和结膜上皮的基底细胞则不染色 CK3、CK12、E-钙黏蛋白和 CK13。检测与细胞外基质 (胶原 IV、Tenascin-C)、细胞-基质黏附 (β- 肌营养不良蛋白、整合素 α3 和 α6)、间充质细胞 (波形蛋白、CD90、CD44)、神经元 (神经丝)、免疫细胞 (HLA-ABC；HLA-DR、CD1、CD4、CD14)、血管 (血管性血友病因子) 和黑素细胞 (SRY-同源盒-10、人黑素瘤黑 45、酪氨酸酶) 的相关标记蛋白的抗体在正常人类眼表面表现出类似的免疫反应性，也存在于正常猪眼表面。只有少数几种抗体（针对 N-钙黏蛋白、纤连蛋白、聚集蛋白、层粘连蛋白 α3 和 α5、黑素-A）在猪组织中似乎没有反应。我们的发现描述了猪眼表面的主要免疫组织化学特性，并为使用猪模型进行研究提供了形态学和免疫组织化学基础。此外，分析的猪眼结构与人类相似，证实了猪眼在研究眼表面生理学和病理生理学方面的潜在有用性。
