Abstract

The present study was carried out in fish Clarias batrachus to evaluate the genotoxicity induced by herbicide pendimethalin and to find out the role of oxidative stress in induced DNA damage. The LC₅₀ value (96 h) of pendimethalin was determined (3.55 mg/L) and based on this, sub lethal test concentrations were calculated as SL-I (1/20th LC₅₀), SLII (1/15th LC₅₀) and SL-III (1/10th LC₅₀) to which fish were exposed for 30, 45 and 60 days. Maximum DNA damage was observed in fish exposed to highest concentration of herbicide and for a particular concentration maximum damage occurs after 30 days then a time dependent decrease was observed. After 30 days the SOD and CAT activity was found to be significantly increased with respect to the control group while it was significantly decreased after 45 and 60 days as compared to 30 days of exposure. Level of lipid peroxidation in pendimethalin exposed fish followed the same pattern. GR activity remained same for all duration of herbicide exposure. The DNA damage is due to ROS generated by the metabolism of herbicide which is evident by alteration in LPO and anti-oxidant enzyme activities accompanied by incidence of DNA damage in a similar way. It can also be concluded that for pendimethalin genotoxicity testing C. batrachus can be used as model organism and comet assay and micronucleus test as effective tools.

摘要

本研究在鱼Clarias batrachus中进行，以评估除草剂二甲戊灵诱导的遗传毒性，并找出氧化应激在诱导的 DNA 损伤中的作用。测定了二甲戊灵的 LC ₅₀值（96 小时）（3.55 mg/L），基于此，亚致死试验浓度计算为 SL-I（1/20 LC ₅₀）、SLII（1/15 LC ₅₀）和SL-III（1/10 LC ₅₀) 鱼暴露 30、45 和 60 天。在暴露于最高浓度除草剂的鱼中观察到最大 DNA 损伤，对于特定浓度，最大损伤发生在 30 天后，然后观察到时间依赖性减少。与对照组相比，30 天后 SOD 和 CAT 活性显着增加，而与 30 天暴露相比，45 天和 60 天后显着降低。暴露于二甲戊灵的鱼的脂质过氧化水平遵循相同的模式。GR 活性在所有除草剂暴露期间保持不变。DNA 损伤是由除草剂代谢产生的 ROS 引起的，LPO 和抗氧化酶活性的改变伴随着 DNA 损伤的发生以类似方式明显可见。C. batrachus可作为模式生物和彗星测定和微核测试作为有效工具。