亚致死剂量高效氯氰菊酯对蚯蚓体内生化指标的影响

Effects of beta-cypermethrin on the biochemical indices of earthworms under the sublethal dose

采用接触滤纸法,测定蚯蚓经亚致死剂量高效氯氰菊酯染毒24 h、48 h和72 h后其体内蛋白含量、超氧化物歧化酶(SOD)活力、过氧化氢酶(CAT)活力和丙二醛(MDA)含量的变化,探讨不同染毒时间和暴露浓度对蚯蚓的毒性效应。结果表明,在高效氯氰菊酯亚致死剂量下,染毒24 h时蛋白含量在50 mg·L^(-1)达到最大值,而染毒72 h时蛋白含量在5 mg·L^(-1)达到最大值,表现为短时间内促进蛋白合成而长时间下抑制。高效氯氰菊酯对SOD和CAT活力的诱导作用明显,SOD活力在低浓度激活,高浓度抑制;CAT活力呈现出先升高后降低的趋势;MDA含量诱导作用不明显,短时间内随暴露浓度升高而升高,但随染毒时间延长趋于正常水平。因此SOD和CAT可作为蚯蚓受到氧化胁迫的指示指标,而MDA无法作为指示指标。此外,各生化指标对高效氯氰菊酯毒性效应的敏感性存在差异,SOD活力影响最大,CAT次之,MDA最小。

In this study, the filter paper contact method was conducted to investigate the toxic effects of beta-cypermethrin under the sublethal dose after 24 h, 48 h and 72 h to discuss the content of protein, superoxide dismutase（SOD） and catalase（CAT） activities and the content of Malondialdehyde（MDA） in earthworm（Eisenia foetida） in different exposure time and concentration. Different changes in the tested earthworm of protein content, SOD, CAT activity and MDA content were observed for application of betacypermethrin. The results showed that the protein content reached the maximum at 50 mg·L^-1in 24 h, while the protein content reached the maximum at 5 mg·L^-1 in 72 h under the sublethal dose of beta-cypermethrin. Protein content showed a time-dependent effect with the beta-cypermethrin： the protein content increased in short time, while it decreased in the long time compared to the controls. Results of exposure tests indicated that beta-cypermethrin had a promoting effect upon the induction of the activities of SOD and CAT in earthworm. The activity of SOD increased in the low concentration group, while it decreased in the high concentration group. The activity of CAT showed a trend of increasing at first and then decreasing during the exposure time. Nevertheless, it was not so obvious to the changes of MDA content, which increased with the exposure concentration in a short time and tended to normal level with the exposure time prolonged. Thus, SOD and CAT could be the indicators of oxidative stress in earthworm, and MDA could not. In addition, the biochemical indicators had different sensitivity to the toxic effects of beta-cypermethrin; SOD was the greatest, followed by CAT and MDA was the minimum.