Objective To investigate the changes of Claudin-3 and Claudin-11,two key components of blood-testis barrier (BTB) on male infertility induced by γ-ray irradiation.Methods Fortytwo KunMing male mice (20-25 g) were divided into one control group,three γ-ray irradiation groups and three estrodiol (E2) intervention groups randomly:Group A,sham controlled; the lower abnominal and scrotal area of the mice in Group B,C,D were irradiated with single dose of 2,6 or 10 Gy 60Co γ-ray after anaesthetizd; 17β-estradiol intervention were initiated in Group E,F,G after 6 Gy γ-ray irradiation via hypodermic injection for 4w at the dose of 1,2,4 μg/d,respectively.Mice were sacrificed 2 w after the last E2 administration.The tubule differentiation index (TDI) was counted in testis sections.InhibinβB,Claudin-3 and Claudin-11 transcription levels were assayed with semiquantitative real time PCR.Claudin-11 protein levels in testis were generated by western blot.Results Compared with sham control group,TDI in three γ-ray irradiation groups were markedly reduced (68.5 ± 6.4,35.0± 6.1,16.3 ± 5.7 vs 100.0,all P＜0.05).InhibinββB mRNA expression level in testis of gourp D was markedly decreased (0.5±0.2 vs 1.0±0.1,P＜0.05).Claudin-3 mRNA levels of group C and D were up-regulated to 2.17 and 3.49 times,respectively.Claudin-11 protein levels were significantly increased to 2.18 and 2.23 times.Compared with group C,TDI in three E2 intervention groups were improved,which were obvious in group F and G (61.7±7.2,55.8±11.9 vs 35.0±6.1,P＜0.05).The InhibinβB mRNA levels were increased,though there were no significant differences (all P ＞0.05).Claudin-3 mRNA levels in group F and G were down-regulated (1.3± 0.2,1.6±0.3 vs.2.2 ± 0.2,all P＜0.05).In group F significantly reduced mRNA level and protein level of Claudin-11 were observed (mRNA:1.2±0.2 vs.1.8±0.2,P＜0.05; Protein:1.5±0.5 vs.2.2±0.3,P＜0.05).It was negatively correlated TDI with mRNA expression levels of Claudin-3 and Claudin-11 in the irradiated testis (rs =-0.884,P＜0.05; rs=-0.758,P ＜0.05,respectively).Conelusions Irradiation could elevated the expression of claudin-3 and claudin-11.