内质网应激在亚硝酸盐致草鱼肝损伤中的作用及调控

As an important intermediate product in the nitrogen cycle of the ecosystem, Nitrite is a common pollutant in aquaculture industry. The rise of nitrite, not only directly affects the growth and quality of breeding, also indirectly pose a threat to human health. Despite previous studies suggesting that nitrite could injure the liver of grass carp (Ctenopharyngodon idellus) via apoptosis, the underlying molecular and cellular mechanisms remain unclear. Endoplasmic reticulum system (ERS) is proposed to involve in the hepatic apoptosis but the role of ERS in the nitrite’s hepatotoxicity was poorly understood. We adopt acute exposure of high-dose nitrite to the grass carp and cultured cell. The ERS dysfunction and its signal transduction mechanisms are determined through biochemical analysis, morphological observation, immunoradiometric assay and molecular biological technique. Our results would elucidate manipulatable molecular mechanisms in acute hepatotoxicity effect of high-dose nitrite. That from a new perspective could provide clues to prevent and/or treat nitriate related diseases in the acquaculture industry and the public health.

亚硝酸盐是生态系统中氮循环中的一种重要中间产物，也是水产养殖过程中常见的污染物。亚硝酸盐的升高，不仅直接影响着养殖品种生长和质量，还间接对人类健康构成威胁。国内外学者和我们的前期工作显示亚硝酸盐暴露能够引起草鱼肝损伤，诱导细胞凋亡，但肝损伤的细胞学和分子机制依然不清。内质网应激（ERS）与组织损伤密切相关，但ERS在亚硝酸盐毒性效应中的作用及其调节机制，迄今知之甚少。本研究采用急性暴露结合细胞染毒方式，应用生化分析、形态学观察、荧光钙影像和分子生物学技术观察亚硝酸盐暴露导致的草鱼肝损伤和由ERS介导的信号级联在肝损伤中的作用及调控。本课题将从新的视觉阐明亚硝酸盐肝毒性的分子机制，为养殖环境控制和草鱼疾病防治提供基础科学依据。

亚硝酸盐是生态系统中氮循环中的一种中间产物，也是水产养殖过程中常见的污染物。为研究氧化应激与内质网应激在亚硝酸盐引致的草鱼肝损伤中发挥何种作用？亚硝酸盐暴露导致草鱼肝损伤时，内质网应激介导的细胞信号转导通路关键分子表达如何变化？本项目开展了亚硝酸盐对草鱼和草鱼肝细胞的作用研究，草鱼暴露实验发现，肝组织明显损伤，血清SOD活性下降，CAT活性上升。肝细胞L8824暴露实验发现，与对照组相比，亚硝酸钠处理组细胞凋亡率显著上升，perk、eif2、atf4、chop、jnk、bax、caspase9、caspase3、ire1α、xbp1s和grp78 mRNA的表达显著升高，bcl-2 mRNA的表达量显著下降，细胞质内钙离子浓度显著上升。与亚硝酸钠单处理组相比，加入IRE1通路抑制剂STF-083010处理组细胞凋亡率显著下降，ire1α、xbp1s、grp78、jnk、bax、caspase3 mRNA表达量显著下降，bcl-2 mRNA表达量显著上升，2-APB和STF-083010两个处理组细胞质内钙离子浓度均显著下降。结果显示，高浓度的亚硝酸钠可诱导草鱼肝细胞凋亡和钙离子紊乱，内质网应激IRE1通路和PERK通路发挥了作用。