邻苯二甲酸二(2-乙基)己酯诱导隐睾对SD幼鼠睾丸生殖细胞凋亡的影响

Effect of di-2-(ethylhexy1)phthalate-induced cryptorchidism on apoptosis of germ cells in infant SD rats

目的探讨环境内分泌干扰物邻苯二甲酸二(2-乙基)己酯[D(i2-ethylhexy1)phthalate,DEHP]作用于SD孕鼠后,对哺乳期雄性幼鼠睾丸组织中生殖细胞凋亡及凋亡基因Bax和Bcl-2表达的影响。方法将30只妊娠第12.5天的SD孕鼠随机分正常对照组、玉米油对照组和DEHP诱导隐睾组,每组10只。玉米油对照组和DEHP诱导隐睾组自妊娠第12.5～19.5天分别每日灌胃玉米油(2 ml)和DEHP(500 mg/kg),正常对照组不给药。取各组出生后第20天的雄性幼鼠睾丸组织,采用Q-PCR法检测睾丸组织中Bax和Bcl-2基因的水平,流式细胞术检测睾丸生殖细胞的凋亡情况。结果 DEHP诱导隐睾组幼鼠睾丸组织中Bax基因mRNA的水平显著高于两对照组(P<0.000 1),Bcl-2基因mRNA的水平显著低于两对照组(P<0.01);DEHP诱导隐睾组幼鼠睾丸生殖细胞凋亡百分率显著高于两对照组(P<0.000 1)。结论孕期暴露环境内分泌干扰物DEHP可引起雄性子代发生隐睾,且隐睾鼠睾丸生殖细胞凋亡率增加,隐睾子代睾丸组织中凋亡基因Bax和Bcl-2的表达有改变,推测其改变可能参与了生殖细胞的凋亡过程,并可能与隐睾继发的远期不育有关。

Objective To analyze the apoptosis of germ cells and the expression of Bax/Bcl-2 in testes of infant male rats with cryptorchidism induced by maternal exposure to di-2-（ethylhexyl ）phthalate （DEHP）. Methods Thirty healthy SD rats on day 12. 5 after pregnancy were randomly divided into normal control, coin oil control and DEHP-exposure groups, ten for each. The rats in corn oil and DEHP-exposure groups were treated with corn oil and DEHP by garage, each at a dosage of 500 mg/kg, once a day on gestation days （GD） 12. 5 ~ 19. 5, respectively, while those in normal control group were untreated. Testes of infant male rats were collected on post-natal day （PND） 20 then determined for expression levels of Bax and Bcl-2 genes by Q-PCR, and for apoptosis of germ cells by flow cytometry. Results The ex- pression level of Bax mRNA in DEHP-exposure group was significantly higher （P 〈 0. 001 ）, while that of Bcl-2 mRNA was significantly lower, than those in two control groups （P 〈 0. 01 ）. However, the apoptosis rate of germ cells in DEHP-exposure group was significantly higher than those in two control groups （P 〈 0. 000 1 ）. Conclusion Maternal exposure to DEHP induced cryptorchidism in male offspring, which promoted the apoptosis of germ cells. Meanwhile, the expressions of Bax and Bcl-2 in testis tissue of rats with cryptorchidism, which was speculated to involve the apoptosis of germ cells and be related to secondary infecundity in future.