线粒体损伤引起大口黑鲈肝功能障碍的分子机制及修复机理

Our previous studies showed that large mouth black bass consumed diets with oxidized fish oil (peroxide value over 277meq/kg) resulted in hepatocytes infiltrated with lipid vacuoles, cell nuclear migration and decreased fluidity of membranes. In vitro hepatocytes culture studies indicated that oxidative stress disturbed cell lipid metabolism and further induced cell apoptosis. What is more, in the studies of mammalian animals found that as the center of cell energy metabolism, mitochondria functions are closely related with liver injury and fatty liver disease, but the specific mechanism is still unclear. Thus, the present project will focus on the mitochondrial. Advanced biological technology including histological analysis, molecular biology and cell biology methods will be used to determine how mitochondrial structure and function vary in the progress of oxidized fish oil induced liver injury, and what are the specific mechanisms that mitochondrial abnormalities and dysfunction involved in this progress. Based on the in vivo and in vitro studies, the protection and repair mechanism of injury liver by trace elements will be evaluated. The expected results of the present project not only will be useful for better understanding the relationship among nutrient, mitochondrial and fish liver injury, and find the solution to protect the fish liver away from injury, but also will provide scientific basis in the development and universal application of practical feed for largemouth black bass in the future.

本实验室前期研究表明，饲料中添加过氧化值超过277meq/kg的氧化鱼油会导致大口黑鲈肝细胞脂滴浸润和细胞核偏位或消失、膜流动性下降，同时体外细胞培养实验研究表明氧化应激会扰乱肝脏脂质代谢并诱导细胞凋亡。此外，在哺乳动物研究中发现作为能量代谢中心的线粒体的损伤与肝脏功能障碍密切相关，但其具体的作用机制尚不清楚。因此，本项目选择线粒体为重要切入点， 采用组织学、分子生物学和细胞生物学等现代生物学技术，更加深入地研究氧化鱼油诱导大口黑鲈肝脏病变过程中，线粒体的结构及功能如何受到影响并发生了怎样的变化, 研究线粒体损伤及功能性障碍在大口黑鲈肝脏病变发生过程中的作用机理。并在此基础上通过在体和离体的方法，研究微量元素对大口黑鲈肝功能的保护机制及肝功能障碍修复机理，进而了解营养物质、线粒体以及肝脏损伤之间的关系，从而找到抑制肝脏损伤的潜在途径。在实践中为大口黑鲈饲料的研制提供理论依据。

线粒体损伤是大口黑鲈肝脏损伤的重要表现形式。本项目研究结果表明氧化鱼油、高糖、高脂对大口黑鲈均会造成线粒体损伤、激发大口黑鲈肝脏炎症反应和细胞凋亡。高脂饲料中补充900 mg/kg的胆汁酸、300-600 mg/kg的绿原酸或者150 mg/kg虾青素均能缓解高脂诱发的大口黑鲈肝脏损伤。本项目研究结果阐释了不同因素引发的大口黑鲈肝损伤机制，对于保障大口黑鲈的健康养殖具有重要意义。