镉暴露致黑斑蛙精巢氧化损伤与DNA损伤

DNA damage and oxidative damage in testes of Rana nigromaculata exposed to cadmium

在实验条件下,将健康性成熟黑斑蛙(Rana nigromaculata)暴露于0.005、0.01、0.05、0.1、0.5和1.0mg·L-1浓度的镉溶液中30d,采用慧星实验检测其精巢细胞DNA损伤,并测定精巢组织中活性氧自由基(ROS)的水平和脂质过氧化主要终产物丙二醛(MDA)含量,探讨镉暴露对黑斑蛙精巢组织的遗传损伤和氧化损伤作用.结果表明,随镉暴露浓度的增加,黑斑蛙精巢组织中的ROS水平明显升高,0.5、1.0mg·L-1镉染毒组与对照组比较有显著性差异;精巢MDA含量以及精巢细胞尾长和尾相显著增加,0.05、0.1、0.5、1.0mg·L-1镉染毒组与对照组比较均有显著性差异;ROS水平、MDA含量以及精巢细胞尾长和尾相与镉暴露浓度之间均呈浓度-效应关系.结果启示,诱导产生自由基并导致脂质过氧化损伤作用增强及DNA损伤是镉引起两栖动物雄性生殖毒性的主要机制之一.

To explore the genetic damage and induced by cadmium exposure in testes of Rana nigromaculata,the healthy adult frogs were exposed to 0.005,0.01,0.05,0.1,0.5 and 1.0 mg · L-1of cadmium solution for 30 days.The DNA damage Rana nigromaculata in the testes was examined using comet assay,and the ROS level and MDA content in the testes were measured.The results showed that the ROS level in testes increased with the increase of cadmium concentration and there were significant differences in the 0.5,1.0 mg · L-1 cadmium-treated groups compared with control group.The MDA content,the tail length and tail moment at the dosages of 0.05、0.1、0.5 and 1.0 mg · L-1 all significantly increased compared with that of the control,and all displayed an obvious concentration-effect relationship.These results show that the primary mechanism of reproductive toxicity on male frogs by cadmium may be that cadmium can induce free radical generation,followed by lipid peroxidation and DNA damage.