镉致黑斑蛙肝脏氧化损伤与金属硫蛋白含量的变化

Effects of Cadmium on oxidative stress and metallothionein of liver in frog Rana nigromaculata

为观察镉对黑斑蛙(Rana nigromaculata)肝脏脂质过氧化产物和金属硫蛋白含量的影响,将黑斑蛙暴露于10.0mg·mL-1浓度的镉溶液中30d,分别测定了黑斑蛙在暴露4、10d和30d时肝脏组织中镉(Cd)、还原型谷胱甘肽(GSH)、金属硫蛋白(MT)和过氧化产物丙二醛(MDA)的含量。实验结果表明,黑斑蛙肝脏中镉的积累量、GSH和MT含量均随着镉暴露时间的延长而显著升高,具有明显的时间-效应关系;在镉暴露的第10天,肝MDA含量明显高于对照组。提示镉可对黑斑蛙肝脏造成氧化损伤,而GSH、MT含量的升高则可能是机体抗氧化损伤的机理之一。

Amphibian populations appear to be declining around the globe.Among many reasons behind this,an important factor may be heavy metals pollution.Heavy metals such as cadmium（Cd）are one of the most fundamental causes of soil and water pollution in industrial and developing countries.The liver is the main target organ affected by Cd toxicity.We used the frog Rana nigromaculata as a test specimen to evaluate the oxidative stress and metallothionein（MT）content of liver under long-term exposure to toxic levels of Cd.Adult frogs were exposed to 10 mg·L-1 Cd in the form of CdCl2 in water for 4,10,and 30 days.The Cd concentration along with metallothionein（MT）,glutathione（GSH）and malondialdehyde（MDA）contents in the liver were detected.The results indicated that Cd accumulation,GSH and MT contents in liver increased significantly in a time-dependent manner.MDA content in liver increased significantly compared with the control groups after 10 days treatment.These results suggest that Cd can induce hepatic oxidative damage,and the increasing of GSH and MT contents might be part of general defense strategies to cope with oxidative stress.