甲基汞致秀丽隐杆线虫神经毒性作用研究

A study of methylmercury neurotoxicity in Caenorhabditis elegans

目的研究甲基汞对秀丽隐杆线虫神经元的损伤作用，观察线虫虫期、染毒方式、检测指标与时间对甲基汞神经毒性的影响。方法L1期、L4期秀丽隐杆线虫用0—300μmol／L甲基汞液体染毒30min或固体染毒24～72h．于染毒开始后的24—72h检测神经元形态及行为学指标。结果甲基汞破坏秀丽隐杆线虫多巴胺神经元与1-氨基丁酸神经元结构的完整性；不论选用L1期还是L4期线虫，采用固体染毒还是液体染毒，甲基汞染毒后24h即可观察到线虫神经元结构、行为功能显著改变；L1期线虫对甲基汞的毒性作用较L4期线虫敏感；身体弯曲频率、头部摆动频率是对损伤最为敏感的行为学指标。结论甲基汞损伤秀丽隐杆线虫多巴胺神经元与y-氨基丁酸神经元；秀丽隐杆线虫能够作为甲基汞神经毒性及机制研究的模式生物。

Objective To evaluate the neuronal damage caused by methylmercury in Caenorhabditis elegans and to observe the effects of C. elegans development stage, route of exposure, toxicity endpoint and detection time on methylmercury neurotoxicity. Methods C. elegans L1 larvae and IA larvae were exposed to 0 ~ 300 μmol/L liquid growth medium containing methylmercury for 30 min or exposed to solid growth medium mixed with methylmercury for 24 ~ 72 h, then changes of neuronal morphology and behavior were measured in 24 - 72 h after exposure. Result Methylmercury destroy the integrity of the structures of dopaminergic （DAergic） neurons and ＂y-aminobutyrie acid （GABAergic） neurons in C. elegans. The obvious changes of C. elegans neuronal structure and behavioral function can be observed after 24 h methylmercury exposure, regardless of the choice of L1 or IA larvae and regardless of whether liquid or solid exposure were used. For methylmercury neurotoxieity in C. elegans, L1 larvae are more sensitive than L4 larvae and body bends and head thrashes were the most sensitive behavior indicators. Conclusion Methylmercury can damage DAergic and GABAergic neurons of C. elegans. C. elegans can be used as model organisms for the study of methylmercury-indueed neurotoxicity and its molecular mechanisms.