长期低剂量锰染毒对子代大鼠睾丸生精细胞线粒体状态和细胞凋亡的影响

Effects of long term low-dose manganese exposure on mitochondria morphology and apoptosis of spermatogenic cells in testis of offspring rats

目的探讨长期低剂量氯化锰染毒对子代大鼠睾丸生精细胞线粒体形态和凋亡的影响。方法健康雌性SD大鼠32只分为对照组、低、中、高剂量组。腹腔注射2、4和8mg/kg MnCl2·4H2O或生理盐水,1次/天,5天/周,共8周,并在妊娠期和哺乳期继续染毒。每组8只12周龄子代大鼠断头处死后,观察睾丸生精小管结构和生精细胞线粒体形态、视神经萎缩蛋白1(Opa1)、动力相关蛋白1(Drp1)、半胱氨酸蛋白酶9(Caspase9)表达和细胞凋亡情况。结果随锰染毒剂量增加,生精细胞层数逐渐减少,细胞排列紊乱、数量减少;中、高剂量组可见线粒体分离、肿胀等表现;中、高剂量组Opa1显著降低(P<0.05,P<0.01),Drp1、Caspase9则随锰染毒剂量增加而递增(P<0.05,P<0.01);锰染毒组生精细胞凋亡指数随锰染毒剂量增加而上升(P<0.05)。结论长期低剂量锰染毒可调节Opa1/Drp1基因表达而影响线粒体功能,导致子代大鼠生精细胞凋亡。

Objective To investigate the effect of long term low-dose manganese exposure on testicular spermatogenic cell mitochondria morphology and apoptosis of male offspring rat. Methods Thirty-two healthy female SD rats were divided into the control group,low,middle and high dose groups. 2,4 and 8 mg/kg MnCl2 ; 4H20 or normal saline was intraperitoneally injected for 8 weeks（once daily, 5 d/week）. The manganese exposure continued during the pregnant period andl lactation period. Eight 12- week-old offspring male rats were killed in each group,the structure of seminiferous tubules and mitochondria morphology in spermatogenic cells were observed. The expression of Opal,Drpl and Caspase9 ,and the apoptosis of spermatogenic cells were detected. Results With the increase of administered-MnCl2 dosage,the number of spermatogenie cell layers decreased,spermatogenic cells arranged in disorder,the number reduced, etc;the mitochondria separation and swelling of spermatogenic cells were found in the middle and high dose groups;the expression of Opal was gradually decreased in the middle and high dose groups（P〈0.05 ,P〈0.01）, while the expression of Drpl and Caspase9 was gradually increased with the manganese dose increase（P〈0.05 ,P〈0. 01） ;the apoptotic index of spermatogenic ceils in the manganese exposuse group was significa/atly increased with the increase of administered- MnCl2 dosage（P〈0.05）. Conclusion Long term low dose of manganese exposure could regulate the expression of Opal/Drpl gene and affect the function of mitochondria,leads to apoptosis of spermatogenic cells in male offspring rat.