氯氰菊酯暴露对青春期雄性小鼠精子发生的影响
Effects of Cypermethrin Exposure during Puberty on Spermatogenesis in Male Mice
-
摘要:
目的 探讨氯氰菊酯暴露对青春期雄性小鼠精子发生的影响及其可能机制。 方法 选择30只5周龄雄性ICR小鼠,随机分为暴露组和对照组,于出生后35天(PND35)至PND70,每天给予暴露组小鼠氯氰菊酯(25 mg/kg)灌胃染毒,对照组以等容积的玉米油灌胃。末次染毒16 h后,处死小鼠,取附睾尾评价精子数量;取睾丸称重并进行组织病理学检查;免疫组织化学法检测睾丸间质细胞;放射免疫分析法检测血清和睾丸组织睾酮水平;蛋白质免疫印迹法测定睾丸组织类固醇激素合成急性调节蛋白(StAR)和睾酮合成关键酶蛋白表达水平。 结果 暴露组小鼠睾丸生精小管管腔内出现大空泡。与对照组相比,暴露组第Ⅶ-Ⅷ期生精小管所占百分比明显下降,附睾尾精子数量明显减少,血清和睾丸组织睾酮含量明显降低,睾丸组织生成StAR的表达明显下调,而氯氰菊酯对小鼠睾丸间质细胞数量无影响。 结论 青春期氯氰菊酯暴露后对小鼠精子发生有损害作用,这可能与睾丸睾酮合成的降低有关。 Abstract:Objective To explore the effects of cypermethrin exposure during puberty on spermatogenesis in male mice. Methods Thirty male mice at postnatal day (PND)35 were randomly divided into two groups. Young male mice in exposure groups were administered with cypermethrin(25 mg/kg)by gavage daily from PND35 to PND70. The controls received corn oil only. Mice were killed 16 h after the last exposure to cypermethrin at PND70. The number of sperm in cauda epieieymidis was counted. Testes were weighed. Histopathological changes of testes were also observed under microscope. Leydig cells in testes were identified by immunostaining for 3β-hydroxysteroid dehydrogenase(3β-HSD). Serum and testicular testosterone was measured by radioimmunoassay(RIA). Protein expression of testicular steroidogenic acute regulatory protein(StAR)and testosterone biosynthetic enzymes were determined using immunoblotting. Results Compared with the control group, the percentage of the seminiferous tubules was markedly decreased in stages VII and VIII. Histological examinations showed large vacuoles appeared in the seminiferous tubules. Results showed sperm count in cauda epieieymidis was obviously decreased in the mice exposed to cypermethrin during puberty. In addition, the level of serum and testicular testosterone was markedly decreased in cypermethrintreated mice. Correspondingly, protein expression of testicular StAR at PND70 was significantly downregulated. Conclusion Pubertal exposure to cypermethrin significantly impairs spermatogenesis in male mice, which might be associated with the decreased testosterone synthesis.
下载:
