亚慢性铜暴露对背角无齿蚌鳃抗氧化系统的影响

为探究淡水环境中铜(Copper, Cu)污染对背角无齿蚌(Anodonta woodiana)鳃抗氧化系统的影响,检测了Cu~(2+)(0.137、0.548、2.192 mg·L~(-1))暴露于背角无齿蚌7、14、21、28 d后,其鳃中超氧化物歧化酶(Superoxide dismutase,SOD)、过氧化氢酶(Catalase,CAT)、谷胱甘肽过氧化物酶(Glutathione peroxidase,GPx)和谷胱甘肽转硫酶(Glutathione-S-transferase,GST)的活性,还原型谷胱甘肽(Reduced glutathione,GSH)和丙二醛(Malondialdehyde,MDA)的含量及总抗氧化能力(Total antioxidant capacity,TAOC)的变化。结果显示:随着Cu~(2+)浓度的增加和暴露时间的延长,MDA含量逐渐上升,表现出明显的"剂量-效应"和"时间-效应"关系;抗氧化酶SOD、GPx和GST活性均被显著诱导(P0.05), CAT活性被显著抑制(P0.05),抗氧化剂GSH含量显著降低(P0.05);Cu~(2+)暴露14、21、28 d,T-AOC与对照组相比均显著升高(P0.05)。总体而言,背角无齿蚌鳃抗氧化系统在Cu~(2+)暴露下被激活,但是鳃组织器官仍然受到了氧化损伤。GPx、GST和GSH对Cu~(2+)暴露响应最为灵敏。

Effect of sub-chronic copper exposure on the antioxidant system in the gills of Anodonta woodiana

To explore the effect of freshwater copper (Cu) pollution on the antioxidant system in the gills of the mussel Anodonta woodiana, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione S-transferase (GST), and the contents of reduced glutathione (GSH), and malondialdehyde (MDA), and total antioxidant capacity (T-AOC) in mussel gills exposed to Cu²⁺ (0.137, 0.548, 2.192 mg·L^-1) for 7, 14, 21 and 28 d, were tested. The results showed that:MDA content increased with increased Cu²⁺ concentration and extended exposure time, showing "dose-effect" and "time-effect" relationships. With Cu²⁺ exposure, the activity of antioxidant enzymes SOD, GPx, and GST were significantly induced (P<0.05), while the activity of CAT was significantly inhibited (P<0.05), in comparison to the control group. In addition, the content of the antioxidant GSH decreased significantly (P<0.05). T-AOC was significantly higher (P<0.05) than the control group after exposure to Cu²⁺ for 14, 21 and 28 d. Overall, the antioxidant system in gills of A. woodiana was activated under Cu²⁺ exposure, but the gills still suffered oxidative damage. In addition, the responses of GPx, GST, and GSH to Cu²⁺ exposure were the most sensitive among the indicators detected in this study, which could provide a scientific basis for using A. woodiana to monitor and assess freshwater copper pollution.