Almubrad Turki, Akhtar Saeed
Cornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
Vet Ophthalmol. 2012 Jan;15(1):36-41. doi: 10.1111/j.1463-5224.2011.00918.x. Epub 2011 Jul 12.
The uniform distribution of collagen fibrils and proteoglycans maintain the transparency of normal cornea. We describe the ultrastructural features of camel cornea including collagen fibrils and proteoglycans (PGs).
Camel corneas (of 6-, 8-, and 10-month-old animals) were fixed in 2.5% glutaraldehyde containing cuprolinic blue in sodium acetate buffer and processed for electron microscopy. The 'AnalySIS LS Professional' program was used to analyze the collagen fibril diameter.
The camel cornea consists of four layers: the epithelium (227 μm), stroma (388 μm), Descemet's membrane (DM), and endothelium. The epithelium constituted 36% of the camel cornea, whereas corneal stroma constituted 62% of the corneal thickness (629 μm). The PGs in the posterior stroma were significantly larger in number and size compared with the anterior and middle stroma. The collagen fibril diameter was 25 nm and interfibrillar spacing 40 nm. Fibrillar structures are present throughout the DM.
The structure of the camel cornea is very different from human and other animals. The unique structure of the cornea might be an adaptation to help the camel to survive in a hot and dry climate. The camel cornea may also be a good model to study the effect of hot and dry climates on the cornea.
胶原纤维和蛋白聚糖的均匀分布维持了正常角膜的透明度。我们描述了骆驼角膜的超微结构特征，包括胶原纤维和蛋白聚糖（PGs）。
将6个月、8个月和10个月大动物的骆驼角膜固定在含有醋酸钠缓冲液中铜啉蓝的2.5%戊二醛中，并进行电子显微镜处理。使用“AnalySIS LS Professional”程序分析胶原纤维直径。
骆驼角膜由四层组成：上皮（227μm）、基质（388μm）、Descemet膜（DM）和内皮。上皮占骆驼角膜的36%，而角膜基质占角膜厚度（629μm）的62%。与前基质和中基质相比，后基质中的PGs数量和大小明显更大。胶原纤维直径为25nm，纤维间间距为40nm。整个DM中都存在纤维状结构。
骆驼角膜的结构与人类和其他动物非常不同。角膜的独特结构可能是一种适应，有助于骆驼在炎热干燥的气候中生存。骆驼角膜也可能是研究炎热干燥气候对角膜影响的良好模型。
