摘要:
探讨草甘膦亚慢性染毒对雄性大鼠睾酮合成的影响。雄性SD大鼠按体重随机分为对照组(0 mg·kg-1)、低剂量组(50 mg·kg-1)、中剂量组(200 mg·kg-1)和高剂量组(800 mg·kg-1),连续灌胃染毒,第4、8和12周时分别处死一批动物,采集血液和脏器。放射免疫分析法检测大鼠血清中卵泡刺激素(follicle stimulating hormone, FSH)、黄体生成素(luteinizing hormone, LH)、睾酮(testosterone, T)、雌二醇(estradiol, E2)水平;HE染色法(苏木精-伊红染色法)观察睾丸病理学变化;免疫组化法检测3β-羟基类固醇脱氢酶(3beta-hydroxysteroid dehydrogenase, 3β-HSD)、类固醇激素合成急性调节蛋白(steroid synthesis of acute regulatory protein, StAR)、细胞色素P450胆固醇侧链裂解酶(cytochrome P450 cholesterol side chain lyase, P450scc)和17β-羟基类固醇脱氢酶(17beta-hydroxysteroid dehydrogenase, 17β-HSD)蛋白表达水平。随染毒剂量和时间的增加,大鼠血清FSH和T水平呈下降趋势,第12周高剂量组FSH水平明显低于对照组(P<0.05),第8周和第12周高剂量组T水平明显低于对照组(P<0.05),LH和E2水平各组间无统计学差异(P>0.05)。组织病理学可见中、高剂量组睾丸生精小管、生精细胞、间质区结构被破坏。随草甘膦染毒剂量的增加,StAR和P450scc蛋白表达水平与对照组相比显著下降(P<0.05),3β-HSD和17β-HSD蛋白表达水平在各组间无差异(P>0.05)。草甘膦能降低血清T水平,抑制T合成相关蛋白StAR和P450scc的表达,干扰T的合成过程,具有雄性生殖毒性作用。
Abstract:
The paper aims to investigate the effect of subchronic glyphosate exposure on testosterone synthesis in male rats. Male SD rats were randomly divided into control group (0 mg·kg-1), low dose group (50 mg·kg-1), middle dose group (200 mg·kg-1) and high dose group (800 mg·kg-1), which were administered to glyphosate by gavage. At 4th, 8th and 12th week, a subunit of animals in each group were killed, and blood and organs were collected. The serum content of follicle-stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and estradiol (E2) were measured by radioimmunoassay. The histopathological changes of testis were observed with hematoxylin-eosin staining. The expression of 3-beta-hydroxysteroid dehydrogenase (3β-HSD), steroid synthesis of acute regulatory protein (StAR), cytochrome P450 cholesterol side chain lyase (P450scc) and 17-beta-hydroxysteroid dehydrogenase (17β-HSD) was measured in the testis using immunohistochemistry method. With the increasing dose and time, the content of serum FSH and T were decreasing. The level of FSH was significantly lower in high dose group than that in control group at 12th week (P < 0.05), and the level of T was significantly lower in high dose group than that in the control group at 8th and 12th week (P < 0.05), whereas there were no difference in serum LH and E2 content between exposed groups and control group (P > 0.05). Histopathology results demonstrated that the testicular spermatogenic tubules, spermatogenic cells and interstitial tissue in rats were destroyed in middle and high dose group. Compared with the control group, the expression level of StAR and P450scc in the testis decreased significantly with the increasing glyphoaste dose (P < 0.05), but there were no difference in 3β-HSD and 17β-HSD expression between the exposure groups and control group (P > 0.05). Glyphosate affects T synthesis and reduces T level in rats by inhibiting the expression of StAR and P450scc. Glyphosate exerts the effect of reproductive toxicity on male animals.
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