Department of Environmental Sciences, Hangzhou Normal University, Xuelin Road 16#, Xiasha Gaojiao Dongqu, Hangzhou, Zhejiang Province 310036, China.
Fish Shellfish Immunol. 2013 May;34(5):1085-93. doi: 10.1016/j.fsi.2013.01.012. Epub 2013 Feb 9.
Nodularin is one of the most conspicuous and widespread pollutants that elicit water ecological hazards to fish, causing serious damage on the immune system and physiological functions. Nodularin can cause oxidative stress-induced apoptosis on fish lymphocytes. The regulatory effects of epigallocatechin-3-gallate (EGCG) at 10, 100, and 1000 μg/L levels on the antioxidant defense system and apoptosis of Carassius auratus lymphocytes exposed to a high dose of nodularin (100 μg/L) were quantified in vitro. EGCG reduced nodularin-induced oxidative damage on fish immune cells. This compound significantly increased the activities of superoxide dismutase and catalase and the level of glutathione but decreased the levels of intracellular reactive oxygen species and malondialdehyde. Flow cytometry results showed that the percentages of apoptotic cells after treatment with 10, 100, and 1000 μg/L EGCG for 12 h reached 27.9%, 19.1%, and 13.7%, respectively. By contrast, the nodularin alone-induced group showed a high percentage of apoptosis (44.2%). Western blot analysis showed the increased expression of bcl-2 and the decreased expression of bax and caspase-3 in EGCG-treated fish lymphocytes. EGCG also inhibited the potential collapse of the mitochondrial membrane. Overall, EGCG can inhibit nodularin-induced apoptosis and protect the normal immunity of fish by regulating bax/bcl-2 and blocking the downstream of mitochondrial apoptosis pathway with increased intracellular antioxidant enzyme activity.
微囊藻毒素是一种最显著和广泛存在的污染物，它会对鱼类的水生态系统造成危害，对鱼类的免疫系统和生理功能造成严重损害。微囊藻毒素可引起鱼类淋巴细胞氧化应激诱导的细胞凋亡。本研究在体外定量评估了表没食子儿茶素没食子酸酯（EGCG）在 10、100 和 1000μg/L 水平对暴露于高剂量微囊藻毒素（100μg/L）的鲤鱼淋巴细胞抗氧化防御系统和细胞凋亡的调控作用。EGCG 降低了微囊藻毒素对鱼类免疫细胞的氧化损伤。该化合物显著增加了超氧化物歧化酶和过氧化氢酶的活性以及谷胱甘肽的水平，同时降低了细胞内活性氧和丙二醛的水平。流式细胞术结果表明，用 10、100 和 1000μg/L 的 EGCG 处理 12 小时后，细胞凋亡的比例分别达到 27.9%、19.1%和 13.7%。相比之下，单独用微囊藻毒素处理的组显示出较高的细胞凋亡比例（44.2%）。Western blot 分析表明，EGCG 处理后的鲤鱼淋巴细胞中 bcl-2 的表达增加，bax 和 caspase-3 的表达减少。EGCG 还抑制了线粒体膜潜在的崩溃。总之，EGCG 可以通过调节 bax/bcl-2 并通过增加细胞内抗氧化酶活性阻断线粒体凋亡途径的下游，抑制微囊藻毒素诱导的细胞凋亡，保护鱼类的正常免疫功能。
