亚急性镉暴露对雄性黑斑蛙生殖毒性的研究

Study on the reproductive toxicity of subacute cadmium exposure in male Rana nigromaculata

在实验条件下,将健康性成熟雄性黑斑蛙暴露于2.5、5.0、7.5和10.0mg·L-1浓度的镉溶液中14 d,观察和分析黑斑蛙的精子数量、精子畸形率,测定精巢组织中酸性磷酸酶(ACP)、乳酸脱氢酶(LDH)、丙二醛(MDA)、谷胱甘肽(GSH)、超氧化歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)的水平和活力,以探讨镉对黑斑蛙的雄性生殖毒性及作用机理.结果表明:①镉可引起黑斑蛙精子数量减少和精子畸形率增加,且呈剂量-效应关系;②镉可引起精巢ACP、LDH酶活性的降低,且随染毒剂量的增加而降低;③镉可引起精巢组织MDA、GSH含量的升高,引起抗氧化酶SOD、GSH-Px活性的降低.由此推论,亚急性镉暴露对黑斑蛙精巢有明显的毒性作用,其机制与镉致黑斑蛙精巢组织标志酶活力的降低和精巢脂质过氧化作用有关.

To study the reproductive toxicity and mechanisms of subacute cadmium exposure in male Rana nigromaculata,healthy adult male frogs were exposed to 2.5,5.0,7.5 and 10.0 mg·L^-1 of cadmium solution for 14 days under controlled conditions.The sperm quantity and sperm deformity of the frogs were recorded and analyzed,and the ACP,LDH,MDA,GSH,SOD,CAT and GSH-Px contents or activities in the testis of the male frogs were determined.The results showed： ① Cadmium caused a decrease in the sperm quantity and an increase in percentage of deformed sperm in a dose-dependent manner;②Testicular ACP activity decreased（p〈0.05） at a dosage of 5.0 to 10.0 mg·L^-1 while LDH activity decreased（p〈0.05） at a dosage of 7.5 to 10.0 mg·L^-1;③Testicular MDA and GSH contents increased（p〈0.05） at dosages of 7.5 to 10.0 mg·L^-1 while GSH-Px activities decreased（p〈0.05） at dosages of 7.5 to 10.0 mg·L^-1.These results suggest that subacute cadmium exposure is toxic to the reproductive systems of male frogs,and the mechanisms may relate to the decreased activities of certain testicular enzymes and the increased lipid peroxidation,so more attention should be given to the effects of heavy metals on reproductive toxicity in amphibians.