Protective role of corneal epithelium against ultraviolet radiation damage
Protective role of corneal epithelium against ultraviolet radiation damage
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DOI：
10.1111/j.1600-0420.2004.00369.x
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发表时间：
2004-12-01
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影响因子：
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通讯作者：
Podskochy, A
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作者：
Podskochy, A
目的：众所周知，角膜上皮强烈吸收紫外线辐射（UVR）。本研究的目的是通过比较UVR暴露对整个角膜和去上皮化角膜的生物学效应来检查角膜上皮对UVR损伤的保护作用。方法：将6只新西兰白化病兔角膜暴露于中心波长约为280 nm的UVR，剂量为012 J/cm（2），可引起生物显微镜下显著的角膜炎。三个角膜在UVR暴露之前经历手动去上皮化。对照组3只家兔仅进行手动去上皮化。给药后76小时处死动物。角膜用苏木精染色，并通过光学显微镜进行评估。结果：角膜只经历了暴露于紫外线显示在治疗区域的上皮细胞的损失。未检测到角膜细胞或基质受损。进行手动去上皮化的角膜显示上皮细胞损失，并且角膜基质的前四分之一中的角膜细胞也损失。然而，手动去上皮后暴露于UVR的角膜显示出非常深的基质损伤。结论：280 nm紫外线单独照射不会对角膜基质和角膜基质细胞造成任何深层损伤。手动去上皮化导致前角膜细胞消失。然而，在去上皮化角膜中，UVR引起的基质损伤非常深。角膜上皮可能通过吸收施加到眼睛的大量UVR能量来保护更深的角膜结构免受UVR损伤。
Purpose: It is known that the corneal epithelium strongly absorbs ultraviolet radiation (UVR). The aim of the present study was to examine the protective role of corneal epithelium against UVR damage by comparing the biological effect of UVR exposure on whole corneas with that on de-epithelialized corneas.Methods: Six New Zealand albino rabbit corneas were exposed to UVR centred around 280 nm at a dose that causes biomicroscopically significant keratitis (012 J/cm(2)). Three corneas underwent manual de-epithelialization prior to UVR exposure. A control group of three rabbits underwent only manual de-epithelialization. The animals were killed 76 hours after treatment. The corneas were stained with haematoxylin and evaluated by light microscopy.Results: Corneas that underwent only the exposure to UVR showed a loss of epithelial cells in the treated area. No damage to keratocytes or the stroma was detected. Corneas that underwent manual de-epithelialization showed a loss of epithelial cells, and also keratocytes in the anterior quarter of the corneal stroma. However, corneas that were exposed to UVR after manual de-epithelialization showed very deep stromal damage. The keratocytes disappeared through the entire thickness of the stroma in the UVR-exposed area.Conclusion: Exposure to UVR at 280 nm alone does not result in any deep damage to the corneal stroma and keratocytes. Manual de-epithelialization causes the disappearance of anterior keratocytes. However, the stromal damage caused by UVR in the de-epithehalized corneas was very deep. The corneal epithelium serves to protect the deeper corneal structures against UVR damage, probably by absorbing a substantial amount of the UVR energy applied to the eye.