Abstract：
A comprehensive light and ultrastructural examination of the cornea in Domestic Pigs (Sus scrofa domesticus) revealed four distinct layers: the anterior epithelium, corneal stroma, Descemet\'s membrane and endothelium. Although Bowman\'s layer was not distinctly identified through histology, histochemical analysis indicated the presence of a rudimentary Bowman\'s layer, possibly vestigial from evolution. Scanning electron microscopy of the outer corneal surface unveiled two cell types, characterized by micro-projections, with light cells exhibiting shorter, thicker projections compared to dark cells. Examination of the inner surface via scanning electron microscopy demonstrated an endothelial layer devoid of cilia and microvilli, yet faint round to oval elevations were observed, potentially representing cell nuclei. Transmission electron microscopy unveiled that basal cells of the anterior epithelium closely adhered to the basement membrane, featuring half desmosomes along the basal surface. These basal cells extensively interconnected through interdigitations and a few desmosomes. The superficial cell layer consisted of a few rows of closely attached flat cells, forming a leak-proof layer with zona occludens. The outermost cells of this layer displayed fine projections to enhance the surface area, facilitating tear film distribution. At lower magnification, Transmission electron microscopy of the corneal stroma revealed alternating light and dark bands, with light bands representing transverse sections of collagen fibril lamellae and dark bands corresponding to longitudinal or oblique sections. Spindle-shaped keratocytes (fibroblasts) were identified as the primary stromal cells, intermingled between the lamellae, and featured long processes in close contact with neighbouring keratocytes. Overall, the histomorphology of the pig cornea resembles that of the human cornea except indistinct Bowman\'s membrane. This detailed understanding of the normal corneal structure in pigs hold great significance for biomedical research, providing a valuable reference for studies involving this animal model.
摘要：
对家猪（Susscrofadomesticus）的角膜进行了全面的光和超微结构检查，发现了四个不同的层：前上皮，角膜基质,Descemet膜和内皮。虽然鲍曼的层没有通过组织学明确识别，组织化学分析表明存在一个基本的鲍曼层，可能是进化造成的。角膜外表面的扫描电子显微镜揭示了两种细胞类型，以微投影为特征，光细胞表现得更短，与暗细胞相比，投影更厚。通过扫描电子显微镜检查内表面，显示内皮层没有纤毛和微绒毛，然而，观察到微弱的圆形到椭圆形的高度，可能代表细胞核。透射电镜显示，前上皮的基底细胞与基底膜紧密粘附，沿着基面具有半桥粒。这些基底细胞通过指间和一些桥粒广泛地相互连接。表面细胞层由几排紧密附着的扁平细胞组成，形成带有透明带闭塞的防漏层。该层的最外面的细胞显示出精细的突起以增强表面积，促进泪膜分布。在较低的放大倍数下,角膜基质的透射电子显微镜显示明带和暗带交替，浅色带代表胶原蛋白原纤维薄片的横截面，深色带对应于纵向或倾斜部分。梭形角膜细胞（成纤维细胞）被鉴定为原代基质细胞，交织在薄片之间，并具有与相邻角膜细胞紧密接触的长过程。总的来说,猪角膜的组织形态类似于人类角膜，除了鲍曼膜不明显。这种对猪正常角膜结构的详细了解对生物医学研究具有重要意义。为涉及该动物模型的研究提供了有价值的参考。
