全氟辛酸(PFOA)对菲律宾蛤仔体内酶活性的影响

The Effects of Perfluorooctanoic Acid(PFOA) on Enzyme Activities in Ruditapes philippinarum

采用半静态毒性实验方法,将菲律宾蛤仔(Ruditapes philippinarum)分别暴露于0.2、2、20μg·L-1的全氟辛酸(perfluorooctanoic acid,PFOA)中,在处理后第1、3、6、10、15、21天分别取样,测定整体组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)、谷胱甘肽-S-转移酶(GST)、7-乙氧基异吩噁唑酮脱乙基酶(EROD)活性和过氧化脂质(LPO)含量。酶活性分析结果显示:PFOA对菲律宾蛤仔组织SOD、CAT和POD活性均呈现先促进后抑制的作用;低浓度组SOD活性在暴露第1天达到最高,显著高于对照组(P<0.01);中高浓度组SOD活性在暴露第6天达到最低;暴露1~15 d,低浓度组CAT活性均显著高于对照组(P<0.05);高浓度组CAT活性在暴露第6天得到显著诱导,其余时间基本处于抑制状态;中浓度组POD活性在暴露第3天即达到最高,高浓度组POD活性基本一直处于抑制状态;随着PFOA暴露时间的延长,菲律宾蛤仔组织LPO含量呈现了先降低后升高的趋势;各浓度组中EROD的活力都显著被诱导(P<0.01),与处理浓度呈正相关;中高浓度组的GST活性在胁迫期间变化比较显著,呈现诱导-抑制的变化规律。研究表明,PFOA暴露能够引起菲律宾蛤仔组织抗氧化酶和生物转化酶的变化,可以与其他敏感性指标一起作为指示早期海洋PFOA污染的生物标志物。

A semi-static toxicity experiment under laboratory conditions was carried out to study the effects of different concentrations （low, 0.2 μg ·L^-1; medium, 2 μg· L^-1; and high, 20 μg ·L^-1） perfluorooctanoic acid （PFOA） on Ruditapes philippinarum. After exposure for 1, 3, 6, 10, 15, 21 days, activities of superoxide dismutase （SOD）, catalase （CAT）, peroxidase （POD）, glutathione-S-transferase （GST）, 7-ethoxy-resorufin-o-deethylase （EROD） and lipid peroxide （LPO） content were measured. Under the effects of PFOA, the SOD, CAT, and POD activities decreased after an initial increase. After 1 day exposure to low concentration PFOA, the SOD activity reached the maximum, being significantly higher than the control （P 〈 0.01）. The SOD activity in the medium and high concentration group reached the lowest at 6th day. After exposure to low concentration PFOA for 1-15 days, the CAT activity was significantly higher than the control. However, the CAT activity was basically inhibited when exposed to high concentration PFOA, except for being the highest on the 6th day. The POD activity in the medium concentration group reached the highest on the 3th day, and was basically inhibited in the high concentration group. As the extension of PFOA exposure time, the LPO content increased after an initial decrease. The EROD activity was significantly induced, and was positively correlated with the concentration of PFOA. The GST activity significantly changed when exposed to medium and high concentrations PFOA during the stress period, and changed by the rule of induction-inhibition. The results showed that PFOA exposure could trigger the changes of antioxidant enzymes and biotransformation enzymes in Ruditapes philippinarum, which could be considered as potential biomarkers to warning PFOA pollution in marine.