Cd Pb单一及复合污染沉积物对铜锈环棱螺肝胰脏SOD和MT的影响

以实验室培养的铜锈环棱螺（Bellamya aeruginosa）为测试生物,采用28d沉积物生物毒性测试研究了Cd、Pb单一及复合污染沉积物对铜锈环棱螺肝胰脏超氧化物歧化酶（SOD）活性和金属硫蛋白（MT）含量的影响,并分析了Cd和Pb对SOD和MT的联合作用特征。结果表明,Cd、Pb单一污染沉积物均对肝胰脏SOD活性具有显著的促进作用,且SOD活性随胁迫浓度的增加而升高,中、高浓度Pb胁迫下的SOD活性显著高于相应浓度的Cd胁迫。低浓度Cd、Pb单一胁迫对MT没有影响,中、高浓度Cd胁迫引起MT水平显著升高,而中、高浓度Pb胁迫导致MT水平显著下降。低、中和高浓度Cd-Pb复合胁迫均对肝胰脏SOD活性具有显著的促进作用,且SOD活性随胁迫浓度的增加而升高,但低于Cd、Pb单一胁迫下的SOD活性。低浓度Cd-Pb联合胁迫对MT没有影响,中、高浓度Cd-Pb联合胁迫导致MT含量显著升高。SOD对Cd-Pb联合胁迫的敏感性高于MT。析因分析表明,Cd-Pb对SOD的联合作用表现为拮抗作用;中、高浓度Cd-Pb对MT的联合作用表现为相加作用,其交互作用机理有待进一步研究。

Effects of Cd,Pb and Combined Contaminated Sediments on Hepatopancreatic SOD and MT in Bellamya aeruginosa

The effects of exposure to individual and joint Cd and Pb contaminated sediments on the hepatopancreatic superoxide dismutase （SOD） activities and metallothionein（MT） contents in Bellamya aeruginosa from lab cultures were investigated through a 28 d bioassay, and the characteristics of combined effects of Cd and Pb on hepatopancreatic SOD and MT were analyzed. The results showed that hepatopancreatic SOD activities were significantly induced by individual Cd or Pb contaminated sediments, and went up with the increase of Cd or Pb concentration, SOD activities under Pb stress with medium and high concentrations were clearly higher than that under Cd stress. Cd or Pb stress with relatively low concentration had no effect on hepatopancreatic MT contents, Cd stress with medium or high concentration sig- nificantly elevated MT contents, however, Pb stress with medium or high concentration significantly decreased MT contents. The hepatopan- creatic SOD activities were also significantly induced by combined stress of Cd-Pb with low, medium, and high concentration, and went up with the increase of Cd-Pb concentrations, but lower than that under corresponding individual Cd or Pb stress. The combined stress of Cd-Pb with low concentration had no effect on MT contents, the combined stress of Cd-Pb with medium and high concentration caused significant elevation of MT. Hepatopancreatic SOD was more sensitive to the combined stress of Cd-Pb than MT. Factorial analysis indicated that the combined effect of Cd and Pb to SOD was characterized as antagonistic effect, and the combined effect of Cd and Pb with medium and high concentration to MT was characterized as additive effect, the mechanisms of Cd-Pb interaction were deserved to be further studied.