Induction of corneal collagen cross-linking in experimental corneal alkali burns in rabbits

Objective: To evaluate the effect of riboflavin-ultraviolet-A-induced cross-linking (CXL) following corneal alkali burns in rabbits. Methods: The right corneas and limbi of ten rabbits were burned using a 1N solution of NaOH and the animals were then divided into two groups: a control group submitted to clinical treatment alone and an experimental group that was treated 1 h after injury with CXL, followed by the same clinical treatment as administered to the controls. Clinical parameters were evaluated post-injury at 1, 7, 15, and 30 days by two independent observers. Following this evaluation, the corneas were excised and examined histologically. Results: There were no statistically significant differences in clinical parameters, such as hyperemia, corneal edema, ciliary injection, limbal ischemia, secretion, corneal neovascularization, symblepharon, or blepharospasm, at any of the time-points evaluated. However, the size of the epithelial defect was significantly smaller in the CXL group (p<0.05) (day 15: p=0.008 and day 30: p=0.008) and the extent of the corneal injury (opacity lesion) was also smaller (day 30: p=0.021). Histopathology showed the presence of collagen bridges linking the collagen fibers in only the CXL group. Conclusions: These results suggest that the use of CXL may improve the prognosis of acute corneal alkali burns.

研究目的：评估核黄素-紫外线A诱导交联（riboflavin-ultraviolet-A-induced cross-linking, CXL）对兔角膜碱烧伤后的治疗效果。
实验方法：选取10只家兔，以1N氢氧化钠溶液烧灼其右侧角膜及角膜缘组织，随后将家兔分为两组：对照组仅接受单纯临床治疗；实验组于造模后1小时接受CXL治疗，后续辅以与对照组一致的常规临床干预。分别于造模后1、7、15及30天，由2名独立观察者对各项临床指标进行评估。评估完成后，摘取角膜组织进行组织病理学检查。
实验结果：在所有观测时间点中，两组在充血、角膜水肿、睫状充血、角膜缘缺血、眼部分泌物、角膜新生血管、睑球粘连以及眼睑痉挛等临床指标上均未出现统计学显著差异。然而，实验组的上皮缺损面积显著小于对照组（p<0.05；造模后15天：p=0.008，造模后30天：p=0.008），且角膜损伤（混浊病灶）范围也更小（造模后30天：p=0.021）。组织病理学检查显示，仅实验组可见连接胶原纤维的胶原桥结构。
研究结论：上述结果表明，CXL可改善急性角膜碱烧伤的预后。