Effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin on testicular function in premature rats.

我们研究了持续低剂量和高剂量TCDD对早产大鼠睾丸功能的影响。1)母鼠给予极低剂量TCDD对仔鼠性腺功能的影响从胎鼠性别分化前至哺乳结束，每周1次给母鼠注射极低剂量TCDD（10 ng/kg），观察雄性仔鼠睾丸和肝脏基因表达的变化。出生后21天的新生大鼠。结果：TCDD组大鼠睾丸重量在3周时增加，6周时减少。睾丸形态学检查中，对照组和TCDD处理组大鼠在3周和6周时生殖细胞、支持细胞和间质细胞的细胞数量无显著差异。而TCDD组大鼠肾小管直径在3周时明显增大。在TCDD处理的大鼠中，CYP 1A 1 mRNA在肝脏中显着增加，而不是在睾丸中在3和6周。Compa ...更多信息 与对照组相比，TCDD处理的肝脏CYP 1A 1 mRNA表达在3周时增加10倍，在6周时增加3倍。与CYP 1A 1相比，AhR和ARNT mRNA表达水平受TCDD处理的影响不大。对照组睾丸组织中抑制素α和β-A mRNA的表达在6周时较3周时下降。然而，TCDD在3周和6周时均未改变Escherichin α、β-A和β-B mRNA的表达。与对照组相比，TCDD治疗组睾丸ER α mRNA水平在3周时显著升高。6周时，TCDD处理的睾丸与对照组之间无显著差异。TCDD处理的睾丸中ER β的表达在6周时增加，但在3周时没有增加。TCDD治疗在3周和6周时未改变睾丸AR mRNA表达水平。2)高剂量（1000和300 ng/kg/w，从出生到8周龄）TCDD的影响。精子活动力下降，TCDD异常损害睾丸功能，尤其是精子生成。少

We examined effects of persistent low and high dose of TCDD on testicular function in premature rats. 1) Effect of very low dose of TCDD administered to maternal rats on gonadal function of neonatal rats.We injected into maternal rats extremely 10 ng/kg of TCDD once a week from the time before the sex differentiation of fetus to the end of breast feeding, and observed the change in gene expression of testis and liver of the male offspring. 21days after birth neonatal rats ware subjected. Results : Testicular weights were increased at 3 weeks, but reduced at 6weeks in TCDD-treated rats. In morphological examination of testes there were no significant differences in cell numbers of germ cells, Sertoli cells and Leydig cells between controls and TCDD-treated rats at 3 and 6 weeks. The diameter of tubules were, however, significantly increased at 3 weeks in TCDD-treated rats. CYP1A1 mRNA in TCDD-treated rats was dramatically increased in the liver, not in the testis at 3 and 6 weeks. Compa … More red with control, the CYP1A1 mRNA expression were increased 10-fold at 3 weeks and 3-fold at 6 weeks in TCDD-treated liver. In contrast to CYP1A1, the levels of AhR and ARNT mRNA expression were not much influenced by the TCDD treatment. The expression of Inhibin alpha and beta-A mRNA in control testis decreased at 6 weeks, compared to those at 3 weeks. However TCDD did not alter the inhibin alpha, beta-A and beta-B mRNA expression at both 3 and 6 weeks. The level of ER alpha mRNA was statistically increased at 3 weeks in TCDD-treated testes compared with controls. There was no significant difference at 6 weeks between TCDD-treated testes and controls. Expression of ER beta was increased at 6 weeks in TCDD-treated testes, but not at 3 weeks. The TCDD treatment did not alter the level of testicular AR mRNA expression at 3 and 6 weeks. 2) Effects of high dose (1000 and 300 ng/kg/w from birth ot 8 weeks of age) of TCDD. Motility of sperm is decreased and abnormality of TCDD impairs testicular function, especially spermiogenesis. Less