Cossu C, Doyotte A, Jacquin M C, Babut M, Exinger A, Vasseur P
Centre des Sciences de l'Environnement, Université de Metz, Metz Cédex, F-57040, France.
Ecotoxicol Environ Saf. 1997 Nov;38(2):122-31. doi: 10.1006/eesa.1997.1582.
The aim of this study was to evaluate the usefulness of antioxidant parameters in the freshwater bivalve, Unio tumidus, as biomarkers of exposure to pollutants and to study their potential interest in predicting toxicity. Selenium-dependent glutathione peroxidase (Se-GPx), non-selenium-dependent glutathione peroxidase (non-Se-GPx), glutathione reductase (GRd), catalase, and superoxide dismutase (SOD) activities; reduced (GSH) and oxidized (GSSG) glutathione levels; and lipid peroxidation were measured in the gills and digestive glands of Unio. Control mussels were encaged and transplanted for 15 and 30 days to sites where the contamination of sediments was analyzed, along a river receiving domestic and industrial sources of pollution. After 15 days of exposure, all antioxidant parameters of the bivalves transferred to the most polluted sites had strongly decreased compared with control values. This was particularly true for Se-GPx and GRd activities, which were inhibited by 60 and 80% in the two tissues, and for GSH levels (80% reduction in the gills and 60% in digestive glands). These decreases were associated in the gills with lipid peroxidation (measured by malondialdehyde content) and with a high level of contamination of sediments by polycyclic aromatic hydrocarbons and polychlorinated biphenyls. In the mussels exposed at the least polluted sites, the same parameters decreased in the gills, but to a lesser extent: 50% for Se-GPx and 32% for GRd activities, and 45% for GSH levels. The gills appeared more sensitive than the digestive glands. After 30 days of exposure, while Se-GPx, GRd, and GSH remained reduced, a significant induction of non-Se-GPx and catalase activities was recorded in the gills, which reflected an adaptation of the transplanted species to their unsafe environment. All the results indicated that antioxidant defense components, namely, Se-GPx, GRd, and GSH, are sensitive parameters that could be useful biomarkers for the evaluation of contaminated aquatic ecosystems. The relationship between the degree of deficiency of antioxidant defenses and lipid peroxidation suggests that these parameters could also be biomarkers for toxicity.
本研究的目的是评估淡水双壳贝类膨腹珠蚌中抗氧化参数作为接触污染物生物标志物的有用性，并研究其在预测毒性方面的潜在价值。测定了膨腹珠蚌鳃和消化腺中硒依赖性谷胱甘肽过氧化物酶（Se-GPx）、非硒依赖性谷胱甘肽过氧化物酶（non-Se-GPx）、谷胱甘肽还原酶（GRd）、过氧化氢酶和超氧化物歧化酶（SOD）的活性；还原型（GSH）和氧化型（GSSG）谷胱甘肽水平；以及脂质过氧化情况。将对照贻贝笼养并移植15天和30天至沿一条接纳生活和工业污染源的河流中沉积物污染情况已分析的地点。暴露15天后，转移至污染最严重地点的双壳贝类的所有抗氧化参数与对照值相比均大幅下降。对于Se-GPx和GRd活性而言尤其如此，这两种酶在两个组织中的活性分别被抑制了60%和80%，谷胱甘肽水平也下降了（鳃中降低80%，消化腺中降低60%）。这些下降与鳃中的脂质过氧化（通过丙二醛含量测定）以及沉积物中多环芳烃和多氯联苯的高污染水平相关。在污染最轻地点暴露的贻贝中，鳃中的相同参数也有所下降，但降幅较小：Se-GPx活性下降50%，GRd活性下降32%，谷胱甘肽水平下降45%。鳃似乎比消化腺更敏感。暴露30天后，虽然Se-GPx、GRd和谷胱甘肽水平仍然降低，但鳃中记录到非硒依赖性谷胱甘肽过氧化物酶和过氧化氢酶活性显著诱导，这反映了移植物种对其不安全环境的适应。所有结果表明，抗氧化防御成分，即Se-GPx、GRd和谷胱甘肽，是敏感参数，可作为评估受污染水生生态系统的有用生物标志物。抗氧化防御不足程度与脂质过氧化之间的关系表明，这些参数也可能是毒性的生物标志物。
