基于IBR模型的Cu2+对厚壳贻贝的毒性效应研究

Toxic Effects of Copper Ion in Mytilus coruscus: An Integrated Biomarker Approach

中文关键词: 厚壳贻贝  铜离子  毒性效应  IBR模型

英文关键词: Mytilus coruscus  Copper ion  Toxic effects  Integrated biomarker response model

中文摘要:

      为了研究Cu2+对厚壳贻贝(Mytilus coruscus)的毒性效应，开展了厚壳贻贝幼体在Cu2+水溶液中的96 h急性毒性效应实验及7 d胁迫实验，将厚壳贻贝内脏团、鳃组织中的超氧化物歧化酶(Superoxide dismutase, SOD)、过氧化氢酶(Catalase, CAT)、脂质过氧化水平(Lipid peroxidation, LPO)以及金属硫蛋白(Metallothioneins, MT)作为生物标志物，应用综合生物标志物响应(Integrated biomarker response, IBR)指数整合4种生物标志物。结果显示，Cu2+对厚壳贻贝幼体的96 h半致死浓度为1.55 mg/L，内脏团、鳃组织各个生物标志物指标呈现出不同的变化趋势，内脏团、鳃组织SOD、CAT活性以及鳃组织MT含量均呈先上升后下降的趋势，内脏团组织MT含量及内脏团、鳃组织MDA含量均呈持续上升的趋势。IBR值呈先上升后下降的趋势，内脏团组织IBR值高于鳃组织。研究表明，生物标志物的变化与Cu2+暴露浓度有关，IBR分析可以辨别不同暴露浓度之间的差异，可以作为量化污染物暴露效应的有效工具。

英文摘要:

      Heavy metal contamination of the natural environment has always been a great concern, because of toxicity and non-biodegradability of the metals. Copper (Cu) is an abundant trace element found in a variety of rocks and minerals and has received much attention due to its widespread use, persistence in nature, tendency to accumulate in and toxicity to aquatic organisms. There are many documented physiological effects of waterborne Cu2+ exposure in a variety of shellfish species, but further research is needed to explain the relationship between Cu2+ and shellfish species. To study the toxicological effects of Cu2+ on mussel Mytilus coruscus, juvenile M. coruscus were exposed to aqueous solutions of Cu2+. Ninety-six-hour acute toxicity effect experiments and 7 days stress experiments were carried out. Biomarkers including superoxide dismutase (SOD), catalase (CAT), lipid peroxidation (LPO), and metallothioneins (MT) in gill and visceral mass were determined after seven days of exposure. Integrated biomarker response (IBR) was calculated by combining multiple biomarkers into a single value in order to assess the responses of different tissues. The acute toxicity experiments showed 1.55 mg/L to be the 96 h median lethal concentration in juvenile M. coruscus. The 7 days stress experimental results showed that the activity of biomarkers were inhibited by all test concentrations and each index hadits own variation trend.Biomarkers SOD and CAT showed activity in gill and visceral mass, MT content in the gill firstly increased and then tended to decrease later, while the MT content in visceral mass and MDA content in gill and visceral mass exhibited an upward tendency. IBR values exhibited an increase at first then tended to decrease later, the IBR value in the visceral mass was higher than that in the gill. Changes of biomarkers’ activity were related to different exposure concentrations. IBR analysis allowed good discrimination between the different exposure concentrations and might be a useful tool for the quantification of various biomarker responses induced by toxic chemicals.