全氟辛烷磺酸盐(PFOS)胁迫对翡翠贻贝抗氧化酶的影响

Effects of Perfluorooctane Sulfonate(PFOS) Exposure on Antioxidant Enzymes of Perna viridis

为了解全氟辛烷磺酸盐(PFOS)对海洋贝类抗氧化防御系统的毒性效应及致毒机理,在实验室条件下研究了PFOS对翡翠贻贝的96h急性毒性,同时探讨PFOS胁迫和净水恢复过程中翡翠贻贝外套膜和内脏团组织中抗氧化指标(SOD活性、GSH和MDA含量)的变化。结果显示,PFOS对翡翠贻贝的96h半致死浓度(LC50)为68.3mg·L-1,安全浓度为6.83mg·L-1。在PFOS胁迫阶段,1mg·L-1浓度组外套膜SOD活性显著性升高(p<0.05),内脏团SOD酶活性显著降低(p<0.05);而PFOS浓度高于1mg·L-1时,外套膜SOD活性显著性降低(p<0.05),内脏团SOD活性显著升高(p<0.05)。PFOS胁迫对翡翠贻贝外套膜和内脏团中GSH含量均有显著的诱导作用(p<0.05),PFOS胁迫15d后各浓度组GSH含量均受到显著的抑制(p<0.05)。翡翠贻贝外套膜MDA含量受PFOS胁迫后显著升高(p<0.05),内脏团MDA含量的变化呈先降低、后升高的规律。净水释放阶段,翡翠贻贝两组织中SOD活性在释放7d后均恢复至对照组水平,GSH含量和MDA含量呈显著升高的趋势(p<0.05)。研究结果表明,PFOS暴露能够引起翡翠贻贝外套膜和内脏团氧化胁迫,但这种损伤的效果不明显,释放短时间后即可自我恢复。

To understand the toxic effect and mechanism of perfluorooctane sulfonate （PFOS） on antioxidantdefense system of marine shellfish, the laboratory experiment was conducted with 96 h acute toxicity test and the semi- static toxicity test. The results showed that 96 h-LC50values of PFOS on Pema viridis was 68.3 mg L＂ t,and the safe concentration of PFOS on Perna virMis was 6.83 mg·L^-1. After the PFOS exposure of Pema v/r/dis, superoxide dismutase （SOD） activities increased in mantle and decreased in visceral significantly at the concentration of 1 mg.L ^-1（p 〈0.05）, which decreased in mantle and increased in visceral with the increasing concentration ofPFOS （p 〈0.05）. Glutathione （GSH）content in mantle and visceral ofPerna viridis was signifi- cantly induced compared with the control （p 〈0.05）, with the increasing exposure time, which was inhibited in each group after 15 d exposure ofPFOS （p 〈0.05）. Malondialdehye （MDA） content in mantle increased signifi- cantly during the period of exposure of PFOS; while MDA content in visceral decreased firstly and then in- creased during the stress stage of PFOS. During the phase of recovery with clear seawater, SOD activities re- covered to the same level with control group, however, there was a rising tendency for all the content of GSH and MDA in 2 tissues ofPerna viridis after 7 - days recovery （p 〈0.05）. The results showed that PFOS expo- sure could cause oxidative stress on mantle and visceral ofPerna viridis, however, the stress compressed by PFOS could be recovered quickly after a short period release of PFOS .