Objecttve To explore the roles of p53,Bax and Bcl-2 in rat lens epithelial cells apoptosis induced by ultraviolet radiation.Methods Healthy SpragueDawley rats (40,6-weeks old,150 g) were selected and divided into 5 groups randomly.After SD rats were injected 100 g · L-1 chloral hydrate (0.35 mL/100 g) intraperitoneally and pupil dilation,the eyes of SD rats were radiated 15 minutes by using UV-B (300-320 nm).The exposed animals were sacrificed at 1 day,3 days,5 days and 7 days after exposure.Both lenses from all animals were extracted.The apoptosis of rats lens epithelial cells was performed by Hoechst 33258 staining.The expression of p53,Bax and Bcl-2 in rat lens epithelial cells at mRNA level was detected by real-time PCR.The distribution and expression of p53,Bax and Bcl-2 were observed by immunohlstochemistry.Results The apoptosis of lens epithelial cells was aggravated after exposure.The expression of p53 and Bax at mRNA and protein level was increased after UV exposure (P ＜ 0.01).But for Bcl-2 the expression both at mRNA and protein level was decreased after a 1 day-exposure(P ＜0.01) and was increased after UV exposure of 5 days and 7 days(P ＜ 0.01).The mRNA expression level of p53 was positively correlated with the Bax (r =0.952,P ＜ 0.01).The expression of p53 and Bax protein were increased after UV exposure,and transferred from cytoplasm to nucleus;While the expression of Bc1-2 protein was decreased at 1 day after UV exposure,and increased gradually at 3 days,5 days and 7 days.Conclusion The apoptotic process of rat lens epithelial cells induced by ultraviolet may be related with p53 regulating the expression of Bax/Bcl-2.