黑斑蛙精巢MDA和抗氧化酶对铅、镉暴露的生态毒性响应

以健康性成熟黑斑蛙为供试动物,以精巢组织丙二醛(MDA)含量、超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物酶(GSH-Px)活性为指标,进行了水体铅、镉暴露的生态毒性响应研究.结果表明:(1)精巢MDA含量随铅、镉暴露浓度的升高而明显增加,且呈明显的浓度-效应关系.说明低水平铅、镉的长期暴露对黑斑蛙精巢具有一定的损伤作用;(2)SOD活性在各处理组响应变化不明显,CAT、GSH-Px活性则被显著诱导,说明GSH-Px、CAT在铅、镉引起的精巢抗氧化损伤中起着重要作用;(3)3种抗氧化酶相比,GSH-Px活性对铅、镉暴露响应最敏感,SOD活性的响应最不明显,精巢GSH-Px活性是指示铅、镉暴露的优选生物标志物。

Ecotoxic responses of MDA and antioxidant enzymes in testes of the frog Rana nigromaculata due to exposures to lead and cadmium

Healthy adult male frogs (Rana nigromaculata) were exposed to lead and cadmium to determine the ecotoxic- responses of MDA content and antioxidant enzyme (SOD, CAT, GSH-Px) activities in testes. The results showed: (1) The MDA content increased significantly with the increase of Pb or Cd concentration, displaying a clear concentration-effect relationship. The changes of the MDA content could show the injured degree in testes of Rana nigromaculata under a long-term exposure to Pb or Cd ; (2) The CAT and GSH-Px activities in testes increased significantly, whereas testicular SOD activity did not changes in all pb or Cd groups compared to control. The results indicated that GSH-Px and CAT activities played an important role in the prevention of oxidant damage in testes in response to the exposure of lead and cadmium; (3) In these three antioxidant enzymes, the GSH-Px activity was most sensitive, and the SOD activity was most insensitive to Pb or Cd exposure. Therefore, the change of GSH-Px activity in testes of the frog Rana nigromaculata is the best biomarker to indicate Pb or Cd exposure.