镉对泥蚶抗氧化酶系统的影响

Effects of cadmium exposure on antioxidant enzyme system of Tegillarca granosa

研究了不同浓度的重金属Cd^(2+)对泥蚶抗氧化酶活性的影响。设置了四组镉的梯度(0、0.025、0.05和0.1 mg·L^(-1),分别在第12、24、48、96和144 h对各组织取样,用泥蚶内脏团与鳃制成酶样,对非特异性免疫抗氧化酶SOD、CAT、GST、GPX进行指标测定。结果表明,在开始的12～24 h,中低浓度组SOD酶的活力与对照组相比有显著性地提高,高浓度组SOD酶的活力变化不显著,随着暴露时间的延长和Cd^(2+)浓度的增加,随后至144 h,高中浓度组SOD酶的活力降至低于对照组水平(P<0.05);GPX和GST活力的变化与SOD变化相似,它们的活性在12～48 h的范围内达到顶峰,然后与对照组相比出现显著下降;中低浓度组的CAT酶活力在第144 h时与对照组相比无显著差异(P<0.05)。在一定程度的Cd^(2+)胁迫会对泥蚶体内的抗氧化酶系统造成损伤。

We investigated the effects of cadmium （Cd^2＋） with different concentrations on the antioxidant enzyme activity of Tegillarca granosa by setting four Cd^2＋ gradients （0, 0.025, 0.05, and 0.1 mg/L） and sampling clam tissue at 12, 24, 48, 96 and 144 h. The activities of antioxidant enzymes were investigated, including superoxide dismutase （SOD）, catalase （CAT）, glutathione peroxidase （GPX）, and glutathione S-transferase （GST） in visceral mass, and gill tissue of T. granosa was as indicator of antioxidant properties. The results showed that SOD activities were significantly higher in the groups with middle （0.05 mg/L） and low （0.025 mg/L） concentrations of Cd^2＋ than those in control group after 12-24 h. However, there was no significant difference between high concentration （0.1 mg/L） and control group. With prolonged exposure time and enhanced Cd^2＋ concentration, significant inhibition was observed between high and middle concentration groups and control group during 48-144 h. The tendency of GPX and GST activity was similar to that of SOD activity, which reached the peak at 12-48 h, and then significantly decreased as compared with control group. Furthermore, CAT enzyme had no significant difference among low, middle and control groups at the 144th hour. So, it was concluded that Cd^2＋ could damage the antioxidant enzyme system of T. granosa by induction of ROS.