长期低水平铅作用对子代大鼠睾丸组织抑制素B亚基表达的影响

Chronic Effect of Low Lead Exposure on Expression of INH B Subunit of Testis in Newborn Rat

目的探讨低水平长期铅作用对雄性大鼠睾丸组织中抑制素B(inhibin B,INH B)亚基表达的影响。方法将12只9周龄SPF级SD雌性大鼠随机分为3组,分别为对照(去离子水)组和低剂量(800 mg/L)、高剂量(1 500 mg/L)乙酸铅染毒组。采用自由饮水方式连续染毒10 d后,按2∶1雌雄同笼。将孕鼠继续分笼喂养,孕期及哺乳期喂养方式同上。仔鼠断乳后,每组选择15只雄性仔鼠,对应分别给予0(去离子水)、300、900 mg/L乙酸铅溶液继续饮水染毒至6月龄。测定血铅和睾丸铅含量及睾丸组织抑制素Bα和βB亚基基因mRNA和蛋白的表达水平。结果与对照组相比,低、高剂量铅染毒组大鼠血铅和睾丸组织中铅含量均较高,而睾丸组织中抑制素Bα和βB亚基mRNA及蛋白的表达水平均下降,差异有统计学意义(P<0.05)。且随着铅染毒剂量的升高,大鼠血铅和睾丸组织中铅含量均呈上升趋势,而大鼠睾丸组织中INH Bα和βB mRNA及蛋白的表达水平均呈下降趋势。结论长期低剂量铅作用所致抑制素Bα和βB亚基表达下降可能参与了铅的雄性生殖毒性过程。

Objective To explore the chronic effect of low lead exposure on the expression of INH B subunit in the testis of the male rats. Methods Twelve female SD rats were randomly divided into three groups and provided deionized water and 0.8,1.5 g/L of lead acetate solution via drinking water respectively,the time of treatment lasted from 10 days before gestation to weaning. Then the fifteen offsprings of each group were treated with lead acetate at the doses of 0,0.3 and 0.9 g/L respectively, through drinking water,the time lasted from weaning to six months old. Blood lead and the testicle lead concentrations and expression of INH Bα and βB genes mRNA and proteins in the testicle were determined. Results Compared with the control group ,the lead levels in blood and testicle in low,high lead exposure groups were significantly higher, the expressions of INH Bα and βB mRNA and protein in rat＇s testicle decreased （P〈0.05）. With the increasing of lead dose, the levels of both blood lead and testicle lead tented to increase,while the expressions of INH Bα and βB mRNA and protein decreased. Conclusion Chronic exposure of low lead results in reduction of INH Bα and βB subunit mRNA and protein expression,this process may be involved in the molecular mechanism of male reproductive toxicity of lead.