沉积物中三丁基锡对铜锈环棱螺肝胰脏抗氧化防御系统的影响

以铜锈环棱螺(Bellamya aeruginosa)为试验对象,采用人工添加TBT的自然沉积物对铜锈环棱螺进行静态暴露实验,研究了沉积物中不同浓度TBT长期暴露(30 d)对铜锈环棱螺肝胰脏的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽(GSH)的影响,以揭示TBT对它们影响的浓度效应关系。结果表明,沉积物中低浓度(100 ng/g)TBT对SOD、CAT和GSH没有影响。当TBT浓度为500～1000 ng/g时,SOD活性呈现浓度依耐性的升高。当TBT浓度为200～1000 ng/g时,CAT活性表现为浓度依耐性的升高。高浓度(2000 ng/g)TBT则导致SOD和CAT活性急剧下降,分别比对照下降了67.33%和54.87%。当TBT浓度为200～1000 ng/g时,GSH含量呈现浓度依耐性的下降,高浓度(2000 ng/g)TBT导致GSH含量急剧下降,比对照下降了76.87%。环境水平的TBT长期暴露对铜锈环棱螺肝胰脏产生了氧化胁迫,高浓度的TBT长期胁迫使肝胰脏受到了严重的氧化损伤。CAT和GSH可以用作环境水平TBT长期暴露的有效生物标志物。

Effects of Sediment-Associated Tributyltin(TBT) on the Hepato-Pancreatic Antioxidant Defence System of Bellamya aeruginosa

Bellamya aeruginosa was chosen as a test species to investigate the effects of chronic exposure (for 30 days) to tributyltin(TBT) spiked sediments on the activities of superoxide dismutase(SOD) and catalase (CAT),as well as the contents of glutathione(GSH) in the hepato-pancreas through a static exposure experiment. The results showed that the chronic exposure to TBT with relatively low concentration(100 ng/g sediment) had effects neither on the activities of SOD and CAT nor on the contents of GSH.The SOD activities presented a concentration-dependent increase at TBT concentrations of 500～1,000 ng/g whilst the CAT activities did so at TBT concentrations of 200～1,000 ng/g.High concentration of TBT(2,000 ng/g),however,would cause a steep decline of SOD and CAT activities with 67.33%and 54.87%drop-off,respectively,compared to the control groups.The GSH contents showed a concentration-dependent decrease at TBT concentrations of 200～1,000 ng/g with sharply dropping 76.87%when TBT at high concentration(2,000 ng/g).As the chronic exposure to TBT at environmental levels would cause oxidative stress to hepato-pancreas of Bellamya aeruginosa,the chronic exposure to TBT with high concentration could give rise to severe oxidative damages to hepato-pancreas.It was suggested that CAT and GSH be used as effective biomarkers for evaluating the chronic exposure to TBT at environmental levels.