Kammergruber Eva, Rahn Carolin, Nell Barbara, Gabner Simone, Egerbacher Monika
Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria.
Department of Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria.
Vet Ophthalmol. 2019 Nov;22(6):778-790. doi: 10.1111/vop.12651. Epub 2019 Feb 14.
The morphology of the corneal epithelium in two age groups of horses is described. Distribution patterns of proliferation-, differentiation-, stem cell-associated markers and cell junction proteins were assessed.
Corneal samples from 12 horses (six foals and six adult horses) were analyzed after H&E staining and immunohistochemistry using the following antibodies: E-cadherin, β-catenin, Connexin 43 (Cx43), tight junction protein 1 (TJP1), cytokeratin (CK) 14, CK 19, CK 3, CK 10, vimentin, Ki67, p63, nerve growth factor (NGF), ABCG2, and epithelial growth factor receptor. Semiquantitative analysis of crypt, limbal, peripheral, and central zone was performed. Semithin and ultrathin sections were used for ultrastructural evaluation of the epithelium.
The height of the epithelium varied between age groups and crypts were consistently present. In the peripheral and central epithelium, three types of basal cells resembling a pseudostratified epithelium were characterized. Potential stem cell markers (CK 14, p63, NGF, and ABCG2) were present in all zones with decreasing frequency toward the center. Cornea-specific differentiation marker CK 3 was not expressed in the most basal cell layer of the limbal epithelium. E-cadherin, β-catenin, and Cx43 revealed a similar apico-lateral signal pattern throughout the entire epithelium; only TJP1 was additionally seen at the basal surface.
This study presents a systematic semiquantitative evaluation of the equine corneal epithelium, showing the presence of crypts as potential stem cell niche with CK 14, p63, NGF, and ABCG2 as relevant markers for cells with regenerative capacity. The pseudostratified arrangement of the basal layer was a unique finding.
描述两个年龄组马的角膜上皮形态。评估增殖、分化、干细胞相关标志物及细胞连接蛋白的分布模式。
对12匹马（6匹驹马和6匹成年马）的角膜样本进行苏木精-伊红染色和免疫组织化学分析，使用以下抗体：E-钙黏蛋白、β-连环蛋白、连接蛋白43（Cx43）、紧密连接蛋白1（TJP1）、细胞角蛋白（CK）14、CK19、CK3、CK10、波形蛋白、Ki67、p63、神经生长因子（NGF）、ABCG2和上皮生长因子受体。对隐窝、角膜缘、周边和中央区进行半定量分析。使用半薄切片和超薄切片对上皮进行超微结构评估。
上皮高度在不同年龄组间存在差异，隐窝始终存在。在周边和中央上皮中，有三种类似于假复层上皮的基底细胞类型。潜在的干细胞标志物（CK14、p63、NGF和ABCG2）在所有区域均有表达，且向中央频率逐渐降低。角膜特异性分化标志物CK3在角膜缘上皮最基底细胞层未表达。E-钙黏蛋白、β-连环蛋白和Cx43在整个上皮中呈现相似的顶侧信号模式；仅TJP1在基底表面额外可见。
本研究对马角膜上皮进行了系统的半定量评估，显示隐窝作为潜在的干细胞龛存在，CK14、p63、NGF和ABCG2作为具有再生能力细胞的相关标志物。基底细胞层的假复层排列是一个独特发现。
