砷染毒大鼠生精细胞凋亡及端粒酶活力的变化

目的观察不同剂量的染砷(As2O3)大鼠生精细胞凋亡及端粒酶活力表达的变化。方法将40只健康雄性清洁级SD大鼠随机分成4组,分别为低、中、高剂量(0.375、0.75、1.5 mg/kg)砷染毒组和对照组,以灌胃法连续染毒16周后计算各组大鼠精子头计数,并计算睾丸脏器系数、每日精子生成量(DSP)。采用TUNEL原位细胞杂交方法检测大鼠生精细胞凋亡,免疫组化法检测大鼠生精细胞端粒酶活力的表达。结果与对照组比较,中剂量组(0.75 mg/kg)和高剂量组(1.5 mg/kg)睾丸精子头计数和DSP均显著降低(P<0.01),生精细胞凋亡指数(AI)显著升高(P<0.01),生精细胞端粒酶活力表达明显降低(P<0.01);每日精子生成量与生精细胞凋亡呈负相关(r=-0.563,P<0.01);生精细胞凋亡与端粒酶活力呈负相关(r=-0.896,P<0.01)。结论一定剂量的As2O3可通过抑制生精细胞端粒酶活力,促进生精细胞凋亡而导致精子生成量减少,产生雄性生殖毒性。

Effects of As203 on Apoptosis and Telomerase Activity of Rat Spermatogenic Cells

Objective To investigate the effect of arsenic(As2O3) on spermatogenic cell apoptosis and the expression of telomerase activity in adult rats.Methods 40 healthy male Sprague-Dawle rats were randomly divided into four groups and they were treated with As2O3 at doses of 0(control group),0.375,0.75 and 1.5 mg/kg body weight respectively through gavage for 16 consecutive weeks.The numbers of testicular sperm head were counted and the coefficient of testicular viscera,daily sperm production(DSP) were calculated in every group.The apoptosis of germ cell was assessed by in situ terminal deoxynucleotityl transferase mediated dTUP nick end labeling(TUNEL) technique.The activity of telomerase in the spermatogenic cells was determined by immunohistochemistry.Results In the testes of As2O3-treated rats,the coefficient of testicular viscera,the number of testicular sperm head and DSP in moderate and high dose groups decreased significantly than that of control(P<0.01).The apoptosis index of germ cell(AI) significantly increased compared with the control group(P<0.01).The activity of telomerase in moderate dose group and high dose group decreased significantly compared with the control group(P<0.01).The dependability analysis between DSP and AI showed a negative correlation(r =-0.563,P<0.01).The negative correlation was significant between AI and telomerase activity of spermatogenic cells(r=-0.896,P<0.01).Conclusion Telomerase activity inhibition is related to the sperm cells decrease caused by arsenic exposure.