镉暴露对不同周龄仔鼠睾丸的影响

Effects of Cadmium Exposure on Testiculus of Mice Offspring at Different Weeks of Age

目的研究孕前、孕期直至哺乳期镉暴露对子代雄鼠睾丸发育的影响及其潜在机制。方法将10周龄C57BL/6J雌雄小鼠随机分为对照组和镉暴露组。12周龄时,两组小鼠分别按雌鼠/雄鼠为2∶1的比例合笼交配。镉暴露组孕鼠继续予低剂量镉喂养至哺乳结束。子代雄鼠哺乳喂养至3周龄断乳。断乳后,部分3周龄雄性仔鼠终止实验,另一部分按亲代分组方式继续喂养至10周龄。结果与对照组比较,镉暴露组子代3周龄及10周龄小鼠睾丸组织内镉浓度明显升高,且10周龄小鼠明显高于3周龄(P<0.05);镉暴露组子代3周龄小鼠睾丸组织未见明显损伤,cleaved caspase-3/caspase-3表达比例无明显变化(P>0.05);镉暴露组子代10周龄小鼠睾丸生精上皮排列紊乱、生精细胞脱落,cleaved caspase-3/caspase-3、BAX/BCL-2的表达比例显著升高(P<0.05),cleaved caspase-8/caspase-8、caspase-12、IRE1蛋白的表达无明显变化(P>0.05)。结论镉可通过胎盘屏障进入子代雄鼠体内并在睾丸内蓄积,对幼年期睾丸发育无明显损伤,但其不断积累可通过增加睾丸细胞凋亡引起青春期雄性大鼠睾丸的损伤。

Objective To study the effects of cadmium exposure before pregnancy,during pregnancy and lactation on testiculus development of male offspring and its potential mechanism.Methods Ten-week-old C57BL/6J male and female mice were randomly divided into control group and cadmium exposure group.At the age of 12 weeks,the two groups of mice were mated according to the ratio of female/male mice of 2∶1.The pregnant rats in the cadmium exposure group continued to be fed with low-dose cadmium until the end of lactation.The male offspring were fed to weaning at 3 weeks of age.After weaning,some 3-week-old male pups terminated the experiment,and the other part continued to be fed to 10 weeks of age according to the parental grouping method.Results Compared with the control group,the cadmium concentration in the testiculus tissue of the 3-week-old and 10-week-old mice in the cadmium exposure group was significantly increased,and that in the 10-week-old mice were significantly higher than that in the 3-week-old mice(P<0.05).There was no significant damage to the testiculus tissue of the 3-week-old mice in the cadmium exposure group,and there was no significant change in the expression ratio of cleaved caspase-3/caspase-3(P>0.05).In the cadmium exposure group,the spermatogenic epithelium of the testis of the 10-week-old mice was disordered,the spermatogenic cells were detached,and the expression ratios of cleaved caspase-3/caspase-3 and BAX/BCL-2 were significantly increased(P<0.05).Conclusion Cadmium can enter the male mice offspring through the placental barrier and accumulate in the testiculus,and has no obvious damage to the development of the testiculus in the juvenile stage,but its continuous accumulation can cause testiculus damage in adolescent male mice by increasing testiculus cell apoptosis.