Effect of hypoxia inducible factor-1α regulating VEGF/PI3K/Akt pathway on apoptosis of testicular Sertoli cells in hypoxic rats and its mechanism
Objective To observe the effect of hypoxia on Sertoli cells,and explore the mechanism of hypoxia inducible factor-1α(HIF-1α)on apoptosis of Sertoli cells in testes of rats under hypoxia through VEGF/PI3K/Akt pathway.Methods Sertoli cells of rat testes were isolated and cultured,and the cells were divided into four groups:group C(normal culture without any treatment);group V(hypoxia culture for 48 h);group H(infected with adenovirus silencing HIF-1α+hypoxia culture for 48 h);NC group(infected with empty adenovirus vector+hypoxia culture for 48 h).The protein expressions of HIF-1α,VEGF,p-Akt,Akt,p-p70S6K,p70S6K,Bax and Bcl-2 were detected by Western blot.The expression and localization of Bax protein in cells were measured by immunofluorescence assay.The apoptosis rate was analyzed by flow cytometry.Results Western blot results showed that compared with group C and H,the protein expressions of HIF-1α,VEGF,p-Akt,p-p70S6K and Bax in group V and NC significantly increased(F=11.71,20.34,10.28,6.096 and 18.55,respectively,each P<0.05),the protein expression of Bcl-2 significantly decreased(F=12.92,P<0.05).The expression of Akt and p70S6K proteins showed no significant difference among the four groups(F=0.572 7 and 0.156 9,respectively,each P>0.05).Immunofluorescence results showed that Bax was mainly expressed in the cytoplasm.Compared with group C and H,the expression of Bax protein in group V and NC significantly increased(F=64.83,P<0.05).The results of flow cytometry showed that compared with group C and H,the apoptosis rates of group V and NC significantly increased(F=9.649,P<0.05).Conclusion Hypoxia-induced apoptosis of Sertoli cells may be caused by the activation of VEGF/PI3K/Akt signaling pathway by the increased expression of HIF-1α.