半乳糖诱导大鼠晶状体上皮细胞凋亡与白内障形成的关系

Relationship between galactose-induced apoptosis of lens epithelial cells and cataractogenesis

目的 研究半乳糖对大鼠晶状体上皮细胞凋亡的影响,并探讨细胞凋亡与白内障形成的关系.方法 将半乳糖单侧眼球后注射Wistar大鼠,裂隙灯下观察晶状体混浊情况,运用流式细胞仪检测各组晶状体上皮细胞C-MYC水平,用末端标记（Tunel）法检测细胞凋亡.结果 半乳糖诱导第7天半数以上晶状体混浊度为Ⅱ期,至14 d时87%晶状体混浊度为Ⅳ～Ⅴ期,在第24天时100%晶状体混浊度Ⅳ～Ⅴ期;乳糖诱导第7天细胞凋亡率为5.6%～8.4%,从第7天开始凋亡细胞数逐渐增多,第14天时细胞凋亡率达30.2%～41.8%,第24天时镜下最多可观察到60%的凋亡细胞;晶状体上皮细胞C-MYC水平在半乳糖诱导第7天和14天均高于对照组（P＜0.05）,24d接近正常水平.结论 半乳糖诱导大鼠白内障形成过程中出现晶状体上皮细胞的凋亡,其机制可能与半乳糖诱导晶状体上皮细胞C-MYC高表达有关.

Objective To explore the relationship between galactose-induced apoptosis of lens epithelial cells and cataractogenesis. Methods Galactose was injected retrobulbarly into Wistar rats. The opacity of lens was examined by slit lamp. The expression of C-MYC was measured by flow cytometer. The apoptosis of lens epithelial cells was observed by TUNEL techniques. Results More than 50 percent of lenses were in the Ⅱ stage of cataractogenesis on the 7 d after galactose induction; Eighty-seven percent of lenses were in the Ⅳ-Ⅴ stage on the 14 d, and 100 percent of lenses were in the Ⅳ- Ⅴ stage on the 24 d. The rate of apoptotic cell on the 7 d and on the 14 d after galactose induction was respectively 5.6% -8.4% and 30. 2% -41.8% , and 60% apoptotic cells were observed on the 24 d. The levels of C-MYC expression in lens epithelial cells induced by galactose on the 7 d and 14 d were higher than that of normal lenses, but the level of C-MYC expression backed to normal level on the 24 d. Conclusion It was suggested that there are some apoptosis of the lens epithelial cells during galactose-induced cataractogenesis and that the apoptosis of the lens epithelial cells might be caused by higher expression of C-MYC.