Effect of manganese on apoptosis and proliferation in spermatogenic cell of rats

Objective To study the effect of manganese chloride on apoptosis and proliferation in spermatogenic cell of rats.Methods 24 healthy male SD rats were randomly divided into three groups and there were 8 rats in every group.The rats of control group were given intraperitoneal injections with normal saline and the exposure groups were administered respectively at the doses of 15 or 30 mg/kg manganese chloride(MnCl_2·4H_2O) for 4 weeks.All rats were injected by intraperitoneal injection once everyday and 5 times in a week.Then all rats were sacrificed and their testes were extracted after 2 weeks.Apoptotic morphologic changes of the spermatogenic cell were observed by transmission electron microscope.The number of apoptosis spermatogenic cell was examined by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) technique.In addition,the expression of proliferating cell nuclear antigen(PCNA) of spermatogenic cell was measured by immunohistochemistry method.Results 1.The apoptotic morphologic changes of spermatogenic cell were observed in every group.2.The apoptosis indexes(AI) of spermatogenic cell in exposure groups were respectively(1.05±0.19)%,(1.80±0.21)% and significant increases of AI were observed when compared with those of the control groups(0.48±0.01)%(P0.01). Moreover,it was increased with dosage of manganese(P0.01).3.Proliferating indexes(PI) in exposure groups were respectively(22.68±2.62)%,(14.25±2.33)% and were more lower than those of control groups(33.25±3.59)%(P0.01).Moreover,it was decreased with dosage of manganese(P0.01).4.There existed a significant negative correlation between AI and PI of rat spermatogenic cell(r=-0.88,P0.01).Conclusion Manganese could promote apoptosis and reduce the expression of PCNA in spermatogenic cell of rat.