3种氯酚类化合物对河蚬的毒性和氧化应激(Toxicity and Oxidative Stress of Three Chlorophenols to Freshwater Clam Corbicula fluminea)

以河蚬(Corbicula fluminea)为试验生物,研究了2,4-DCP、2,4,6-TCP和PCP的急性毒性和21d慢性毒性,并在同一条件下测试了这3种氯酚类化合物对河蚬软体组织抗氧化系统的影响.结果显示:2,4-DCP、2,4,6-TCP和PCP对河蚬96hLC50值分别为19.25(17.58～21.20)、41.98(35.48～58.24)和0.23(0.18～0.27)mg·L-1;以致死作为观察指标,其21d无观察效应浓度(NOEC)和最低观察效应浓度(LOEC)值分别为1.00、2.00、0.06mg·L-1和2.00、4.00、0.08mg·L-1.3种氯酚类化合物对河蚬软体组织抗氧化系统几种酶的活性均表现出了不同程度的影响,其中对SOD和GSH-Px的影响最为明显.2,4,6-TCP和PCP对SOD均表现为抑制作用,对GSH-Px表现为先诱导后抑制;2,4-DCP对SOD和GSH-Px表现为明显的诱导作用;3种氯酚类化合物对CAT均表现为明显的诱导作用;对GST活性也有一定影响,但与对照组相比变化范围不大(62.95%～137.04%).3种氯酚类化合物暴露后生物体抗氧化酶有不同的响应,表明不同氯酚类化合物所导致的氧化损伤及其应激机制不同.

Toxicity and Oxidative Stress of Three Chlorophenols to Freshwater Clam Corbicula fluminea

Acute and 21d chronic toxicities of 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP) and pentachlorophenol(PCP)to Asiatic clam(Corbicula fluminea)were tested. Variations of antioxidant enzyme activities in soft tissue of the clam were measured simultaneously in the chronic exposure. Results showed that the 96h LC50 of 2,4-DCP, 2,4,6-TCP and PCP to Corbicula fluminea were 19.25(17.58～21.20), 41.98(35.48～58.24), and 0.23(0.18～0.27)mg· L-1, respectively. The 21d No-Observed Effect Concentrations (NOEC) and the Lowest Observed Effect Concentrations (LOEC) regarding to the mortality were 1.0, 2.0, 0.06mg·L-1 and 2.0, 4.0, 0.08mg·L-1, respectively. Both superoxidase dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly affected by exposure of three chlorophenols: the activity of GSH-Px were induced at first and then inhibited when exposing 2,4,6-TCP and PCP, while SOD was induced at all exposure time. For 2,4-DCP exposure, the activities of SOD and GSH-Px were induced significantly. The activity of catalase (CAT) was also induced significantly, while the activity of glutathione S-transferase (GST) was only slightly affected when exposed to three chlorophenols(62.95%～137.04% of the control). Exposure to different chlorophenols could result in different response modes of antioxidant enzymes and the oxidative and protective mechanisms induced by different chlorophenols were different.