六溴环十二烷暴露对红鳍笛鲷脑乙酰胆碱酯酶和组织氧化应激的影响及评价

Evaluation on Effects of Hexabromocyclododecane on Acetylcholinesterase and Oxidative Stress in the Brain of Juvenile Crimson Snapper( Lutjanus erythopterus)

六溴环十二烷(C_(12)H_(18)Br_6,简称HBCD)是近年来在环境中广受关注的优先污染物和高产量化学品。实验室条件下以红鳍笛鲷为研究对象,选取其脑组织非特异性生物标志物超氧化物歧化酶(superoxide dismutase,SOD)、谷胱甘肽巯基转移酶(glutathione S-transferases,GST)和丙二醛(malondialdehyde,MDA)及特异性生物标志物乙酰胆碱酯酶(acetylcholinesterase,ACh E)为指标研究了不同浓度HBCD溶液(8.6μg·L^(-1)、43.0μg·L^(-1)和215μg·L^(-1))暴露96 h对红鳍笛鲷脑组织的氧化损伤和神经毒性效应,同时结合综合生物标志物响应指数(integrated biomarker responses index,IBR),对HBCD造成的胁迫水平和毒性效应进行评价。结果表明:HBCD对红鳍笛鲷脑组织中SOD活性和GST活性表现出不同程度的诱导效应,其中暴露初期SOD活性与HBCD浓度呈正相关,但随暴露时间延长与HBCD浓度呈负相关;HBCD对MDA含量和ACh E活性表现出诱导或抑制且存在剂量依赖性,低浓度组MDA含量表现为先抑制后诱导的过程,ACh E活性表现为先诱导后抑制;中浓度组MDA含量和ACh E均表现为抑制效应;高浓度组MDA含量表现为先诱导后抑制的过程,ACh E活性表现为先抑制后诱导。IBR分析结果表明4种生物标志物对HBCD胁迫的敏感性分别为SOD>GST>ACh E>MDA,且中、高浓度组的胁迫效应最明显。

Hexabromocyclododecane（ C12H18Br6,HBCD） has recently become the priority pollutant and the high production volume chemical due to its persistence in environment. In this study,we evaluated the potential oxidative damage and neurotoxicity of different concentrations of HBCD solutions（8. 6 μg·L^-1,43. 0 μg·L^-1and 215 μg·L^-1） on brain tissues of juvenile crimson snapper（Lutjanus erythopterus）. Both nonspecific biomarkers,including SOD,GST and MDA,and specific biomarkers（ e. g.,AChE） were selected. The stress level and toxic effects of HBCD were also evaluated using the integrated biomarker responses index（ IBR）. We found that the effects of HBCD on SOD and GST activities of brain tissues were different. SOD activities were positively related with the HBCD concentration during the early exposure period,but negatively related under prolonged exposure time. MDA contents and AChE activities were induced or inhibited after adding HBCD and the effects were dose-dependent. For low-dose groups,MDA contents dropped significantly at first and then increased significantly,while AChE activities showed the opposite process. For medium-dose groups,both MDA contents and AChE activities were induced. For high-dose groups,MDA contents increased significantly at first and then dropped significantly,while AChE activities showed the opposite process. The IBR analysis showed that the stress sensitivity of four kinds of biomarkers to HBCD solutions was ranked as： SOD〉 GST〉 AChE 〉MDA. The stress effects under medium and high concentrations were much stronger than those under other concentrations.