镉对背角无齿蚌外套膜和鳃抗氧化酶活性及脂质过氧化的影响

Effects of cadmium on antioxidant enzyme activities and lipid peroxidation in the mantle and gill of the freshwater bivalve A.woodiana woodiana

为了探究镉对背角无齿蚌(A.woodiana woodiana)外套膜和鳃抗氧化酶活性及脂质过氧化的影响,按照96 h的LC50为134.9 mg·L-1,分别于镉(Cd2+)浓度为4.22、8.43、16.82、33.7和67.45 mg·L-1,染毒24、48、72和96 h后测定背角无齿蚌外套膜和鳃中抗氧化酶包括超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GPX)和过氧化氢酶(CAT)活性及脂质过氧化产物丙二醛(MDA)的含量.结果表明,背角无齿蚌在不同浓度镉(Cd2+)溶液中经急性毒性处理24、48、72和96 h后,外套膜抗氧化酶活性呈现"抑制-诱导-抑制"的规律性变化,鳃抗氧化酶活性呈现"诱导-抑制"的规律性变化.镉处理后的背角无齿蚌外套膜和鳃SOD、GPX和CAT活性,表现出明显的组织差异性,且鳃诱导SOD、GPX和CAT活性较外套膜早.经镉处理以后,外套膜和鳃中MDA含量呈现升高趋势,高浓度镉处理组较对照组脂质过氧化损伤出现显著差异(**p<0.01),具有剂量-效应和时间-效应.

To explore the effects of cadmium on antioxidant enzymes activities and lipid peroxidation in the mantle and gill of the freshwater bivalve A. woodiana woodiana, according to LCs0 of 134.9 mg·L^-1 at the 96th hour, bivalves were exposed to different concentrations of cadmium （4.22, 8.43, 16.82, 33.7 and 67.45 mg·L^-1 ） for 24, 48, 72 and 96 hours. Activities of superoxide dismutase （SOD） , glutathione peroxidase （GPX） , catalase （CAT） and the contents of malondialdehyde （MDA） were determined with the mantle and gill of the treated bivalves. Changes in activities of antioxidant enzymes from the mantle exhibited a pattern of inhibition-induction-inhibition while branchial enzymatic activities were initially induction, followed by inhibition with increasing Cd concentration. The induction of enzymatic activities following the Cd treatment appeared to be tissue-specific, with the induction of hranchial enzymatic activities occurring earlier than that for the mantle. The contents of MDA were found to continuously increase in both the mantle and the gill. Our results also showed a significant increase （ ＊ ＊ p 〈 0.01 ） in lipid peroxidation in the mantle and gill after treatment with a high concentration of cadmium, indicating a concentration-dependent and time-dependent manner.