紫贻贝长期暴露于亚致死剂量的林丹和阿特拉津下的组织学反应(英文)  

Histological responses of marine mussel Mytilus edulis to long-term exposure to sublethal-level of lindane and atrazine

作　　者：Nahla S.El-SHENAWY Richard GREENWOOD Ismail M.ABDEL-NABI 

机构地区：[1]Department of Zoology,Faculty of Science,Suez Canal University [2]School of Biological Sciences,University of Portsmouth

出　　处：《动物学报》2007年第5期899-909,共11页ACTA ZOOLOGICA SINICA

摘　　要：为开发快速、敏感的生物标记物以监测海洋贝类生物中是否存在农药,我们检测了双壳动物紫贻贝长期暴露在亚致死剂量的丙体六氯环乙烷(林丹,γ-HCH)和2-氯4-乙胺基-6异丙胺基-1,3,5-三氮苯(阿特拉津)下的组织学变化。紫贻贝容易积累环境中的杀虫剂,因此,本研究旨在阐明农药的生物积累与组织病理学效应之间的关系。利用GC/MSD分析法定期对贻贝和水样中的林丹与阿特拉津含量进行测定。将贻贝在实验室中培养21天,以使其代谢适应于带有水质控制的封闭式不间断流动系统。随后,30只贝暴露于亚致死剂量的林丹(0.9 mg/L)或阿特拉津(3.583 mg/L)溶液中56天。实验期间,控制重要的参数,比如温度和盐度分别控制在18℃和34‰。在处理28天和56天后取样,检测组织学损坏及吸收的农药量。暴露的紫贻贝每克干重分别能聚集约304.8-372.0μg/g林丹和83.3-137.4μg/g阿特拉津。组织学改变高度集中在鳃的上皮和外套膜组织;上皮与相邻的组织形成分离状态。组织病理学结果显示,抗性机制的激活使紫贻贝能在亚致死压力下存活。组织病理效应范围从浸润反应到以血淋巴细胞出现间质细胞反应为特征。因此,在农药聚集部位的组织学和超微结构的改变是敏感的,并与农药的生物积累具有正相关关系,说明这些改变可能作为农药暴露的生物标记物。Histological changes in tissues of the sentinel bivalve species Mytilus edulis were examined following a long-term exposure to sub-lethal levels of gamma-hexachlorocyclohexane （γ-HCH） and 2-chloro-4-ethylamino-6-isopropylamino-s-triazine （atrazine） to investigate the potential of such changes as fast and sensitive biomarkers of exposure to pesticides. M. edulis readily bioaccumulates environmental pesticides, and in this project the relationship between accumulation of selected pesticides and histopathological effects was studied. Mussels and water samples were analysed for γ-HCH and atrazine by GC/MSD. The mussels were taken to the laboratory and kept for a 21 day period in order to let their metabolism adjust to a continuous closed flow system with quality water control. After that period, 30 organisms were exposed either to sublethal concentrations of γ-HCH （0.9 mg/L） or atrazine （3.583 mg/L） for 56 days. During the experiment, important parameters such as temperature （18℃） and salinity （34%0） were controlled. Mussels were sampled to determine histological damage, and the concentration of pesticide levels at 28 and 56 days. Exposed organisms accumulated around 304.8 -372.0 and 83.3 - 137.4 μg/g dry weight of γ-HCH and atrazine, respectively. Most histological alterations were highly localized in the epithelium of the gills and mantle tissues; epithelia were found to be detached from the remaining tissue parts. Histopathological results showed the activation of resistance mechanisms that allow mussels to survive under sublethal stresses. The histopathological effects ranged from infiltration responses up to mediated cellular responses, characterized by the presence of hemolymph cells. Histological and ultrastructural changes in various tissues were positively correlated with the bioaccumulation of the pesticides, suggesting that they may serve as biomarkers for pesticide exposure .

关 键 词：指示生物 慢性影响 扫描电镜 鳃 外套膜 

分 类 号：X834[环境科学与工程—环境工程]