镉对背角无齿蚌鳃和肝脏氧化损伤的影响

Oxidative damage of cadmium on liver and gill of freshwater mussel Anodonta woodiana woodiana

为了探明镉(Cd^(2+))对背角无齿蚌(Anodonta woodiana woodiana)鳃和肝脏的氧化损伤,根据Cd^(2+)96 h的半致死浓度,设置了5个处理组(4.22、8.43、16.86、33.72、67.45 mg·L^(-1))和1个空白对照组,分别处理24、48、72、96 h,通过实验测定其鳃与肝脏中过氧化氢(Hydrogen peroxide,H_2O_2)含量、抗超氧阴离子能力(Superoxide anion,O_2^-·)、抑制羟自由基能力(Hydroxyl radical,·OH)及总抗氧化能力(Total antioxidant capacity,T-AOC)。结果显示,在同一时间,与对照组相比,背角无齿蚌鳃和肝脏中H_2O_2含量整体表现为极显著性升高(P<0.01);鳃抑制·OH能力出现极显著性降低(P<0.01),肝脏抑制·OH无明显变化;鳃和肝脏抗O_2^-·能力均呈极显著性降低(P<0.01);鳃和肝脏T-AOC呈极显著性升高(P<0.01)。研究表明,肝脏作为背角无齿蚌的解毒器官,对外源Cd^(2+)的污染较为敏感,可以作为水体中镉污染监测的靶器官;鳃和肝脏抗O_2^-·能力均呈降低趋势,说明O_2^-·可能是镉致使背角无齿蚌氧化损伤的首要因素,可以作为水体镉污染监测的生物指标。

In order to determine the oxidative damage in liver and gill of Anodonta woodiana woodiana by cadmium（Cd^2＋）, this study designed five different concentration treatment groups which were 4.22, 8.43, 16.86, 33.72, 67.45 mg·L^-1, according to the medial lethal concentration of Cd^2＋, as well as one control group. It were measured and analyzed of the contents of hydrogen peroxide, resistant ability of superoxide anion and hydroxyl radical in the gill and liver during 24, 48, 72 and 96 h. Furthermore, the capacity of total antioxidant of gill and liver were also monitored. The results showed that the contents of hydrogen peroxide increased significantly compared with the control group in the gill and liver, while the ability of resisting superoxide anion was decreased significantly（P0.01）. For inhibiting the hydroxyl radial,the liver and gill indicated different results, which showed that the gill had the notable lower ability while there was no significant difference found in liver. The findings of the experiments showed that liver was more sensitive to Cd^2＋toxicity and liver could be as the target organ in Anodonta woodiana woodiana that could be used as the indicator organ for the water contamination. Moreover, the results indicated that the superoxide anion maybe the crucial factor for the oxidative damage of cadmium, so, it could be used as the biomarker for the cadmium contamination of freshwater.