[The expression of calpain II in rat lens epithelial cells of hydrogen peroxide-induced cataract].

OBJECTIVE: To study the expression and role of calpain II in rat lens epithelial cells (LECs) of hydrogen peroxide (H(2)O(2))-induced cataract. METHODS: Rat lenses were cultured in vitro and cataract was induced by 2 mM H(2)O(2). The lenses were observed under microscope. Simultaneously, photographs and picture analyses were done in order to detect the variation of the opacity. The expression of calpain II in rat LECs was detected with immunohistochemical method and compared with a control group. RESULTS: When the lenses were cultured in 2 mM H(2)O(2) for 3 hours (h), the expression of calpain II in rat LECs was increased obviously. There was significant difference between H(2)O(2)-induced and the control group (P = 0.006). After 6 h, vesicles appeared at the equator of the lenses. There was a significant difference between the result of picture analysis of H(2)O(2)-induced and control group (P = 0.013). So the expression of calpain II in rat LECs of H(2)O(2)-induced cataract was increased before cataract occurred. After induced with H(2)O(2) for 24 h, the opacity of lenses and the expression of LECs were both increased as compared with that at 6 h (P = 0.000, 0.000). CONCLUSION: H(2)O(2) can enhance the expression of calpain II in rat LECs which may play a role in the mechanism of oxidative stress-induced cataract.