Pinho G L L, da Rosa C Moura, Maciel F E, Bianchini A, Yunes J S, Proença L A O, Monserrat J M
Departamento de Ciências Fisiológicas, Fundação Universidade Federal do Rio Grande, 96201-900 Rio Grande, RS, Brazil.
Ecotoxicol Environ Saf. 2005 Jul;61(3):361-5. doi: 10.1016/j.ecoenv.2004.12.014. Epub 2005 Jan 26.
Microcystins are hepatotoxins suspected to generate oxidative stress. This mechanism was evaluated in gills of the estuarine crab Chasmagnathus granulatus (Decapoda, Brachyura). Adult male crabs were fed ground beef with or without vitamin E (600 mg/kg). Microcystin (1.21 microg/kg) was daily administered through forced ingestion, for 7 days. After exposure, catalase activity was reduced in posterior gills of crabs supplemented with vitamin E. A lower increment in glutathione S-transferase activity (GST) was observed in organisms pretreated with vitamin E and then exposed to microcystin with respect to those exposed to the toxin but not pretreated with the vitamin. Pretreatment with vitamin E also increased nonproteic sulfhyrdil groups and this effect was not observed after microcystin exposure. The fact that supplementation with antioxidants such as vitamin E modulates GST activity indicates the direct or indirect involvement of microcystin in oxidative stress generation.
微囊藻毒素是一种疑似会产生氧化应激的肝毒素。本研究在河口蟹颗粒巨螯蟹（十足目，短尾亚目）的鳃中评估了这一机制。成年雄蟹被喂食添加或不添加维生素E（600毫克/千克）的碎牛肉。通过强制喂食每天给予微囊藻毒素（1.21微克/千克），持续7天。暴露后，补充维生素E的蟹后鳃中的过氧化氢酶活性降低。与未用维生素预处理而仅暴露于毒素的生物体相比，用维生素E预处理后再暴露于微囊藻毒素的生物体中谷胱甘肽S - 转移酶活性（GST）的增量较低。维生素E预处理还增加了非蛋白质巯基，而微囊藻毒素暴露后未观察到这种效应。补充维生素E等抗氧化剂可调节GST活性这一事实表明微囊藻毒素直接或间接参与了氧化应激的产生。
