低浓度锌及其EDTA配合物长期暴露对鲫鱼肝脏锌富集及抗氧化系统的影响

选择幼龄鲫鱼为材料 ,研究锌(Zn²⁺)及其配合物(Zn-EDTA)低浓度长期暴露(40d)对鲫鱼(Carassius auratus)肝脏锌富集和抗氧化防御系统的影响 .结果表明 ,鲫鱼肝脏中锌的积累量随锌暴露浓度的升高而增加,且Zn²⁺处理明显高于Zn EDTA处理 .2种形态锌对鲫鱼肝脏超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT)和谷胱甘肽过氧化物酶 (GPx)均表现出抑制作用 ,其中Zn²⁺暴露浓度与酶活性之间存在良好的剂量效应关系;Zn²⁺在低浓度时对谷胱甘肽转硫酶(GST)有诱导作用 ,高浓度时为抑制作用 .Zn EDTA对GST活性始终产生抑制作用 .CAT与GPx对锌暴露比GST和SOD更为敏感 ,适合作为水环境锌污染的早期监测指标 .

Effects of Long-Term Exposure of Low Level Zinc and Zn-EDTA Complex on Zinc Accumulation and Antioxidant Defense System in Liver of Carassius auratus

The effects of low level zinc(Zn²⁺)and its EDTA complex on zinc accumulation and antioxidant enzymes,such as catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPx) in the liver of Carassius auratus are studied after 40 day exposure. The results show that zinc accumulation is significantly increased with higher zinc concentration. When fish are exposed to Zn-EDTA, the zinc accumulation in the liver of fish increased slightly according to the control. SOD, GST, CAT and GPx activity all decrease with adding to Zn²⁺ and Zn-EDTA in waters. However, the decrease of CAT and GPx activities of fish liver are alleviated with the addition of EDTA. The GST activities increased at lower concentration solutions (<0.05mg·L^{-1/sup>, however its activities were inhibited at higher Zn2+ solution (>0.05mg·L-1). These results suggest that CAT and GPx are more sensitive to low zinc exposure than SOD and GST, and they can be served as biomarkers of low concentration zinc exposure in aquatic ecosystem.}