海水中原油对双齿围沙蚕(Perinereis aibuhitensis)的急性毒性效应及其体内抗氧化酶活性的影响

近年来海洋溢油事故频发，增加了溢油污染对海洋生物及海洋生态系统的暴露风险.为阐明海洋溢油事故对海洋生物的毒性效应，以双齿围沙蚕（Perinereis aibuhitensis）为受试生物，研究了不同质量浓度的海水原油溶液对双齿围沙蚕的急性毒性效应及抗氧化酶活性的影响.结果表明:双齿围沙蚕的死亡率与海水中原油暴露浓度呈正相关，暴露24、48及72 h的LC₅₀（半致死浓度）分别为13.08、9.80和8.37 g/L；暴露72 h后，双齿围沙蚕组织液中MDA（丙二醛）的含量均高于对照组，其中1.0 g/L暴露组显著高于对照组（P < 0.05），且随暴露浓度的增大而升高；GST（谷胱甘肽巯基转移酶）的活性被显著诱导，且随暴露浓度的增大而升高；0.1 g/L原油暴露下，CAT（过氧化氢酶）和SOD（超氧化物歧化酶）的活性被显著诱导，当暴露浓度达到0.5 g/L时，CAT的诱导程度减弱，而SOD则受到抑制.研究显示，海水中的原油对双齿围沙蚕具有显著急性毒性效应，且0.1 g/L的原油暴露即可导致双齿围沙蚕产生脂质过氧化，脂质过氧化程度随暴露浓度的升高而增强；0.1 g/L原油暴露能显著诱导双齿围沙蚕体内抗氧化酶的活性，且随着海水中原油暴露浓度的增加，GST的诱导程度增强，CAT的诱导程度减弱，SOD的活性则受到抑制. 

Acute Toxicity and the Effects on Antioxidant Enzyme Activities of Polychaete Perinereis aibuhitensis Exposed to Crude Oil in Seawater

The frequent occurrence of marine oil spill accidents in recent years increased the exposure risks of oil spills to marine biota and ecosystems. In the present research, acute toxicity and effects of crude oil contaminated seawater on antioxidant enzyme activities were studied using polychaete Perinereis aibuhitensis as a test organism. The mortality of P. aibuhitensis was positively correlated with the crude oil concentration in seawater; the 50% lethal concentrations (LC₅₀) at 24, 48 and 72 h were 13.08, 9.80 and 8.37 g/L, respectively. After exposure for 72 h, the content of malonaldehyde (MDA) in the tissue fluid of P. aibuhitensis exposed to crude oil was higher than that in the control group. The MDA content in the exposure group of 1.0 g/L crude oil concentration was significantly higher than that in the control group (P<0.05), and the MDA contents increased following the increase in crude oil concentration in exposure. The activity of Glutathione-s-transferase (GST) in the tissue fluid of P. aibuhitensis was significantly induced when exposed to crude oil, and increased following the increase in concentration of crude oil in exposure. The activities of Catalase (CAT) and superoxide dismutase (SOD) in the tissue fluid of P. aibuhitensis were significantly induced when exposed to low crude oil concentration (0.1 g/L), but the induction of CAT decreased and SOD was inhibited when exposed to high crude oil concentrations (0.5 g/L). The results showed that there was acute toxicity for P. aibuhitensis when exposed to crude oil in seawater. Moreover, there was significant phenomenon of lipid peroxidation even when exposed to crude oil concentrations of 0.1 g/L. Additionally the activity of antioxidant enzymes was affected significantly.