CNTF对糖尿病小鼠角膜神经和上皮修复的作用及机制研究

Neurotrophic keratopathy is a common disease in ophthalmology. It is difficult to be cured in clinic. Corneal limbal stem cells maintain the normal proliferation and differentiation of corneal epithelia, and some neurotrophic factors play important roles in promoting corneal epithelium repair, however, the research is quite deficient about corneal neurotrophic factors in controlling the corneal limbal stem cells function, corneal epithelium and nerve repair. Our previous researches found that the expression of ciliary neurotrophic factor (CNTF) in corneal epithelia was significantly lower in diabetic mice than in normal mice, while exogenous CNTF can significantly promote the corneal nerve and corneal epithelial wound repair. Based on the above results, the effects of CNTF on corneal limbal stem cell proliferation and differentiation in vitro and in vivo, and corneal epithelial wound and corneal nerve repair in animal models is to be further investigated in this study.

近年来，随着糖尿病发病率的上升，糖尿病导致的神经营养性角膜病变日益受到眼科医师的关注，其主要特征表现为角膜神经密度下降及角膜上皮迁延不愈，可反复发生角膜上皮脱落，治疗棘手。但是，目前对于糖尿病性角膜病变缺乏基础研究。本课题组的前期研究发现：糖尿病小鼠角膜上皮中CNTF表达量降低，外源性补充CNTF可显著促进角膜上皮的修复。糖尿病小鼠角膜上皮下神经丛密度下降，外源性补充CNTF可显著促进角膜上皮下神经修复及轴突再生。本项目拟采用糖尿病小鼠角膜神经及上皮损伤模型，深入研究CNTF对角膜神经修复及角膜上皮修复的作用及其机制；进一步研究CNTF及其相关信号通路在糖尿病条件下的变化和干预治疗的可行性。本研究有助于阐明CNTF在介导角膜神经调控角膜缘干细胞更新和角膜上皮修复过程中的作用机制，为糖尿病性角膜病变的治疗提供新的干预策略。

本项目通过小鼠的体内、外实验，研究角膜上皮、角膜上皮下神经损伤后修复的分子机制及其影响因素。经过3年的研究，本课题主要从以下三个方面取得了进展：1. CNTF可促进小鼠角膜上皮干/祖细胞的克隆形成能力、促进TKE2细胞系干细胞干性及增殖能力标志的表达，并且可以提高小鼠角膜上皮干细胞关键转录因子TCF4的表达，进而促进角膜上皮的修复。2. Stattic可抑制糖尿病小鼠及体外培养的小鼠三叉神经节细胞的轴突生长，减少三叉神经节细胞中p-STAT3的表达，而CNTF可恢复P-STAT3被减弱的表达，进而促进小鼠三叉神经节细胞轴突的生长。3. MiR-17可抑制小鼠角膜上皮的修复，并抑制TKE2细胞纤维黏连蛋白（FN）的表达进而抑制TKE2细胞的粘附和迁移；增加FN可以促进小鼠角膜上皮损伤后的修复。通过本课题的研究，共发表Cornea、Medicine (Baltimore)、BMC Ophthalmol等SCI收录期刊论文6篇，国内眼科核心期刊论文5篇，在国内及国际专业学术会议上发言4次。