Study On The Inhibitory Effect Of EGCG On Cataractous Lenses Of Rabbits Induced By Dexamethason.

Objective:To observe the inhibitory effect of EGCG on cataractous lenses of rabbits Dexamethason peroxide induced.To explore the validity of EGCG on the treatment of Dexamethason induced cataract formation.Methods:Cultured normal rabbit lens in vitro were randomly divided into 4 groups: the control group(A),the group treated by Dexamethason(B),the group treated by Dexamethason peroxide and EGCG(10mmol/L,20mmol/L)(C1,C2).The transparence and apoptosis ratio of lens on the time points of 3d,5d,7d were determined image analysis and flowcytometry. At the end of the incubation period, the lens were examined for biochemical parameters such as total antioxidant capacity(T-AOC),Na+-K+ATP and glutathione peroxidase(GSH-Px) by spectrophotometrically. at the same time,the histological changes of all lenses were examined by electron microsopies and verified the occurrence of programmed cell death and the expression of caspase-3 was detected by the immunohistochemical method,as well as by terminal deoxyribonucleotide transferase—mediate dUTP nick end labeling(TUNEL)detection,we examined the affect of EGCG on the number of Dexamethason—induced rabbit lens epithelial cell with apoptosis,the related comparisons and statistic analyses were carried out.Result:1.The transparence of the group treated by Dexamethason and EGCG and the group treated by Dexamethason and EGCG in association are higher than that of the group treated by Dexamethason and tower than that of the control group.The differences among groups were statistically significant(P<0.01).2.The levels of T-AOC,Na+-K+ATP and GSH-Px were decreased significantly in Dexamethason group compared with those of them in control group.3.The opacityof thelenses in every group was evaluated.The longer incubated with Dexamethason treatment,the more the active expression of caspase-3 in lens epithelial cell were found,the latter was positively correlate with opaque degree of lens and to a certain extent EGCG had a dose-dependent action in less the active expression of caspase-3 in rabbits lens epithelial cell and relieve opacity of lens.4.The TUNEL method revealed that the apoptosis rate for LECs in Dexamethason group was apparently higher than that for the control group(P<0.01);There was a significant difference between the EGCG in association with tocopherol group and the Dexamethason group(P<0.01).Conclusion:these experiments confirmed that:the antioxidant—EGCG can evidently inhibit LEC apoptosis which may be the cellular and molecular mechanisms of EGCG preventing and delaying the development of the cataract .