染锰大鼠生精细胞凋亡中caspase-3 mRNA、凋亡蛋白酶活化因子-1及多聚ADP核糖聚合酶的表达变化

目的:研究染锰诱导的大鼠生精细胞凋亡过程中,天冬氨酸特异性半胱氨酸酶-3(caspase-3)mRNA和凋亡蛋白酶活化因子-1(Apaf-1)、多聚ADP核糖聚合酶(PARP)的表达及其关系,探讨它们在生精细胞凋亡过程中的作用。方法:雄性SD大鼠,设立空白对照组、低剂量(15 mg/kg MnCl_2)和高剂量(30 mg/kg MnCl_2)组。实验组分别染锰4周和6周,空白对照组给予等容生理盐水,给药途径均为腹腔注射,TUNEL法检测生精细胞凋亡,原位杂交法和免疫组织化学法检测生精细胞caspase-3 mRNA、Apaf-1和PARP的表达。结果:与空白对照组比较,各染锰组生精细胞凋亡指数(AI)和caspase-3mRNA阳性细胞率均显著升高,Apaf-1和PARP阳性细胞率均显著降低。染锰剂量相同,6周与4周组比较,以及染锰时间相同,高剂量组与低剂量组比较,生精细胞AI和caspase-3 mRNA阳性细胞率均显著升高,Apaf-1和PARP阳性细胞率均显著降低。各组大鼠生精细胞AI与caspase-3 mRNA阳性细胞率呈正相关,与Apaf-1和PARP阳性细胞率呈负相关。结论:锰可影响大鼠生精细胞caspase-3 mRNA表达,促进Apaf-1和PARP分解,导致生精细胞凋亡,产生生殖毒性效应。

Expression changes of caspase-3 mRNA,apoptosis protease activating factor-1 and poly ADP-ribose polymerase in apoptosis of spermatogenic cells of rats exposed to manganese

Objective:To determine the effect of caspase-3 mRNA and apoptosis protease activating factor-1 (Apaf-1),poly ADP-ribose polymerase (PARP) in apoptosis of spermatogenic cells of rats exposed to manganese.Methods:SD male rats were randomly divided into one control group and two manganese chloride (MnCl2) (15 mg/kg,30 mg/kg) groups respectively.After being exposed to manganese for 4 and 6 weeks,the apoptosis of spermatogenic cells was e xamined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling(TUNEL) technique.The expression of caspase-3 mRNA in spermatogenic cells was investigated by in situ hybridization,and the expression of Apaf-1 and PARP was detected by immunohistochemistry.Results:Compared with the control group,AI and caspase-3 mRNA-positive-cell rates were increased but the Apaf-1 and PARP-positive-cell rates were decreased.Among the same dose and same time manganese exposure groups,AI and caspase-3 mRNA-positive-cell rates were increased but the Apaf-1 and PARP-positive-cell rates were decreased in the 15 mg/kg MnCl2 group compared to the 30 mg/kg MnC12 group.There existed a positive correlation between AI and the caspase-3 mRNA-positive-cell rate and a negative correlation between AI and the Apaf-1-positive-cell rate and PARP-positive-cell rate.Conclusion:Manganese could upregulate the expression of caspase-3 mRNA,and decompose Apaf-1-positive-cell rate and PARP-positive-cell rate,which might be one of the important molecular mechanisms of reproductive toxicity of manganese.