摘要:
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96 h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96 h半致死浓度(LC50)为68.3 mg·L-1,安全浓度为6.83 mg·L-1。在PFOS胁迫阶段,1 mg·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1 mg·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15 d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7 d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。
Abstract:
To understand the toxic effect and mechanism of perfluorooctane sulfonate (PFOS) on antioxidant defense 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-LC50 values of PFOS on Perna viridis was 68.3 mg L-1, and the safe concentration of PFOS on Perna viridis was 6.83 mg·L-1. After the PFOS exposure of Perna viridis, 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 of PFOS (p < 0.05). Glutathione (GSH) content in mantle and visceral of Perna viridis was significantly induced compared with the control (p < 0.05), with the increasing exposure time, which was inhibited in each group after 15 d exposure of PFOS (p < 0.05). Malondialdehye (MDA) content in mantle increased significantly during the period of exposure of PFOS; while MDA content in visceral decreased firstly and then increased during the stress stage of PFOS. During the phase of recovery with clear seawater, SOD activities recovered to the same level with control group, however, there was a rising tendency for all the content of GSH and MDA in 2 tissues of Perna viridis after 7-days recovery (p < 0.05). The results showed that PFOS exposure could cause oxidative stress on mantle and visceral of Perna viridis, however, the stress compressed by PFOS could be recovered quickly after a short period release of PFOS.
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