阿维菌素对黑斑侧褶蛙毒理效应的研究

Study on Toxicological Effect of Avermectins on Pelophylax nigromaculatus

本文选用生物农药阿维菌素作为染毒试剂,以农田中常见黑斑侧褶蛙Pelophylax nigromaculatus为研究对象,分别从急性毒性、亚急性毒性、遗传毒性和生理毒性四个方面的实验综合探讨了阿维菌素对黑斑侧褶蛙的生态毒理学效应。急性毒性实验结果表明,阿维菌素对黑斑侧褶蛙24h、48h、72h、96h的LC50分别为:0.3227mg/L、0.0966mg/L、0.0623mg/L、0.0432mg/L,其对黑斑侧褶蛙的安全浓度(SC)为0.004316mg/L。亚急性毒性实验结果表明,暴露期间,随着浓度的升高,毒害作用越大,其对黑斑侧褶蛙肝脏组织损害也越大,而经恢复期后,各实验组肝脏组织受损程度较暴露期都有降低。红细胞核异常及微核诱导实验结果表明,微核和核异常现象与阿维菌素浓度的相关性有一定的范围;随着时间的延长,红细胞核异常率及微核率先上升后下降。肝脏LDH同工酶聚丙烯酰胺凝胶电泳实验结果表明,在一定时间条件下,随浓度的升高,LDH1和LDH2酶带活性呈现降低趋势,LDH4酶带活性无明显变化,LDH5酶带活性先升高后再降低,在同一浓度条件下,随着时间的延长,肝脏LDH同工酶活性均呈升高的趋势。实验结果表明阿维菌素对黑斑侧褶蛙能够造成不同程度的生理、病理及遗传性损伤。

This study mainly investigated the toxicological effect of the biological pesticide avermectins on Pelophylax nigromaculatus, which was made up of four parts： acute toxicity, subacute toxicity, physical toxicity （micronucleus and nuclear anomalies in erythocytes of P.nigromaculatus induced by avermectins）, and genetic toxicity （changes of lactate dehydrogenase （LDH） isozyme in liver）. Results were shown as follows： the acute toxicity test results showed that the LC50 of avermectins on P.nigromaculatus for 24 h, 48 h, 72 h and 96 h were 0.3227 mg/L, 0.0966 mg/L, 0.0623 mg/L, 0.0432 mg/L, respectively. The safe concentration （SC） of avermectins was 0.004 316 mg/L. Subacute toxicity test results showed that in the exposure period, along with the increasing of the concentration of avermectins, the toxic effects on liver tissue of P.nigromaculatus became greater. After recovery period, the extent of liver tissue damage of each experimental group was decreased. The results of micronucleus and nuclear anomalies in erythocytes induced by avermectins showed that, there was a range between the frequencies of nuclear anomalies and micronucleus and concentration of avermectins. The frequencies of nucleus anomalies and micronucleus increased first and then decreased as time went on.Polyacrylamide gel electrophoresis results of liver LDH isozyme showed that, within a certain time, the activities of LDH1 and LDH2 decreased along with concentration increasing. No significant change was observed in the activities of LDH4. The activities of LDH5 increased at first and then reduced. The activities of liver LDH isozyme would increase when treated by the same concentration of avermectins. In conclusion, avermectins exposure to P.nigromaculatus can lead to varying degrees of physical, pathological and genetic damage.