溴氰菊酯在罗非鱼组织中的累积及对谷胱甘肽-S-转移酶的影响

Accumulation of Deltamethrin in the Tissue of Tilipia and the Influence on Activity of Glutathione-S-transferase

以罗非鱼Tilipia为试验鱼类,研究了其暴露于不同浓度溴氰菊酯后其组织中溴氰菊酯的含量和谷胱甘肽-S-转移酶GST活性的动态变化。结果表明,罗非鱼肌肉和肝脏组织中的GST的正常值分别为(4.39±0.2)U.mg.prot-1和(13.3±0.3)U.mg.prot-1。采用不同浓度的溴氰菊酯处理罗非鱼25 d,除了1.0μg.L-1浓度组罗非鱼体内无明显累积,GST与对照组相比无显著差异外,其余各浓度组均有一定的累积,同时GST发生了明显的变化。GST的变化规律为先升高后降低,即溴氰菊酯对罗非鱼体内的GST是先诱导后抑制,且这种变化幅度肝脏比肌肉大。2.0￣10.0μg.L-1浓度组经15￣20 d可在肌肉和肝脏中达到累积-释放的动态平衡,最大累积系数分别为1.85和2.20。溴氰菊酯在罗非鱼组织中达到累积平衡时,其累积量与GST活性呈较明显的负相关。研究表明,1.0μg.L-1以下的溴氰菊酯对罗非鱼没有生化毒性影响,罗非鱼组织中的溴氰菊酯累积量和GST可用来评价农药对鱼类的毒性效应。

The accumulation of dehamethrin and the activity of Glutathione-S-transferase（GST） in the tissue of tilipia, which exposed to different concentrations of deltamethrin were studied. GST was an important enzyme in the fish body, with the main effects of removing the free groups and detoxifying. When deltamethrin accumulated in the tissue offish, the activity of GST changed. The normal value of GST in the muscle and liver of tilipia was （4.39±0.2）U · mg· prot^-1. and （13.3±0.3）U·mg· prot^-1. respectively. After treated 25 days, the group of 1.0 μg. L^-1 dehamethrin had no effect on the activity of GST in the tissue of tilipia, and the dehamethrin was not accumulated in the fish body, while, the other groups could obviously change the activity of GST and accumulated in the fish body. At the first 6 days, when deltamethrin was accumulated in the fish body, GST in the tissue of tilipia could be induced, so the activity of GST increased. Afterward it began to decrease.The change of GST in liver of tilipia was much obvious than that in muscle. Deltamethrin could be accumulated in tilipia when the concentration was 2.0-10.0μg·L^-1. The deltamethrin content was 3.70-8.80 μg·kg^-1 and 3.96-9.46μg·kg^-1 in muscle and liver of tilipia respectively. After 15-20 days, the deltamethrin reached the balance of accumulation and released. The biggest accumulation coefficient was 1.85（in muscle） and 2.20（in liver） respectively. There were much better relationships between the accumulation of deltamethrin and the activity of GST, with the correlation coefficients of 0.814 7 and 0.971 6 in muscle and liver. 1.0 μg·L^-1 of deltamethrin had no biochemical toxicity to tilipia and could be regarded as a kind water standard to protect fishes. The accumulation of deltamethrin and GST in fishes could be used as a better biomarker to estimate the toxicity of the pesticide to fishes.