Connection Of FAS With Apoptosis Of The Lens Epithelial Cells In Hydrogen Peroxide-Induced Cataract

Background: Oxidative stress can induce apoptosis in lens epithelial cells (LECs),and epigallocatechin-3-gallate (EGCG) can inhibit apoptosis, but mechanism of them is unknown.Objective: To observe the connection of Fas with apoptosis of LECs in Hydrogen Peroxide (H₂O₂)-induced cataract and the effect of EGCG on the expression of Fas and apoptosis of LECs.Method: Lenses isolated from normal adult rabbits were cultured in vitro and divided into three different groups: the blank control group, the group treated by H₂O₂(0.3mmol/L),the group treated by H₂O₂(0.3mmol/L) and EGCG(0.1mmol/L). After 72 hours of incubation, alteration of opacity was observed by photography and picture analysis; the histomorphology of lenses were examined under the light microscope; the levels of SOD,CAT and MDA were tested by spectrophoto metrically.We examined the apoptosis of LECs by terminal deoxyribonucleotide transferase-mediate dUTP nick end labeling (TUNEL) detection as well as by the immunohistochemical, the expression of Fas was detected. Result: The transparence in H₂O₂ group was lower than that in the blank control group. The transparence in the blank control group was lower than that in the blank control group but higher than that in H₂O₂ group The differences among groups were statistically significant (P<0.05). Under the light microscope, the blank control group: LECs arranged regularly and tightly. LECs tightly linked with the anterior capsular membrane and the cotex fiber of lens. LECs appeared normal and nucleus appeared unanimously. The cortex fiber layers of lens arranged tightly and regularly and no hollow and bubble appeared. H₂O₂ group: LECs arranged disorderly, some of LECs decoherenced partly from the anterior capsular membrane and the cotex fiber of lens, cells waxed and nucleus appears multiformity and the cortex fiber layers of lens arranged disorderly, much vesicle and water fissure among them. EGCG group: All parts of lens appeared closed to the control group. The levels of SOD and CAT were decreased and level of MDA was increased significantly in H₂O₂ group compared to the blank control group .The level of MDA was decreased significantly but the levels of other indexes were increased in EGCG group compared with H₂O₂ group. The apoptosis rate for LECs in H₂O₂ group was apparently higher than that in the blank control group and EGCG group. Comparing with the blank control group, the expression of Fas protein was found up-regulated significantly in H₂O₂ group and Comparing with H₂O₂ group that was down-regulated in EGCG group. The differences among groups were statistically significant (P<0.05).Conclusion: Up-regulating the expression of Fas protein could be one of the mechanism through that H₂O₂ induced apoptosis of LECs. EGCG could down-regulate that and reduced apoptosis of LECs.