肝性脑病（HE）机制不清致临床治疗效果不佳。我们前期研究发现：TAA诱导HE小鼠全程可见黑质网状部内线粒体解耦联蛋白UCP2表达增高，下调UCP2能有效缓解HE行为同时，还能纠正HE所致神经元特异性氯离子外向转运体KCC2表达降低、氯稳态失衡以及线粒体功能异常。以上提示UCP2受线粒体介导下调KCC2氯调控功能可能是肝性脑病发生发展的关键事件之一。本课题以此为契机，以GAD67-GFP转基因小鼠为工具，以黑质网状部（SNr）为靶区，以TAA肝性脑病模型为研究对象：①明确HE各时程SNr内UCP2表达水平及线粒体功能改变情况；②找出HE状态下UCP2反向调控KCC2功能的作用机制；③搞清UCP2增多和线粒体功能异常对GABA能神经传递的调控及机制；④最终在整体动物水平探索干预UCP2和线粒体功能对HE行为学影响。本项目旨在从线粒体角度阐明肝性脑病机制，为临床有效治疗肝性脑病提供新思路。

Hepatic encephalopathy (HE) is a major neuropsychiatric disorder that occurs in patients with severe liver failure.The mechanisms by which liver failure leads to altered motor function remained unclear.We have focused on the involement of altered mitochondrial funtion and mitochondrial uncoupling protein 2 (UCP2), considering that it has been identified as a critical determinant of fatty acid utilization by adult neurons, within the substantia nigra pars reticulata (SNr) in the toxin thioacetamide (TAA)-induced hepatic encephalopathy using glutamic acid decarboxylase 67-green fluorescent protein knock-in transgenic mice (GAD67-GFP knock-in mice). We have found that, during the first and advanced phase phases of the encephalopathy, the UCP2 expression increases remarkably. Interestingly, the treatment with the targeted suppression of UCP2 within the SNr by lentivirus-mediated RNAi could effectively prevent HE-induced hypolocomotion, while such administration produced a significant effect on the decreased neuron specific chloride transporter KCC2, imbalance of chloride homeostasis and disfunction of mitochondria, considering such changes have been identified to be induced by TAA hepatic encephalopathy. Our data suggest that UCP2 would exert its reverse action on chloride homeostasis regulated by KCC2, and mitochondrial function, at the substantia nigra pars reticulata level, which may be critically involved in the development and maintenance of hepatic encephalopathy. But the exact mechanism associated with hepatic encephalopathy needs to be clarified. Thus we will first use mitochondria isolation and detection methods to investigate the changes of UCP2 expression and four major mitochondrial functions (ATP synthesis, calcium homeostasis, redox reaction and membrane stablity) within the substantia nigra pars reticulata in TAA-induced hepatic encephalopathy model of GAD67-GFP knock-in mice. Second, we will detect the underlying signaling pathways between UCP2 and KCC2 function by molecularand morphological methods in vivo and in vitro.Third, we will use the combinationof patch-clamp recordings and single-cellRT-PCR methods to studythe mechanismof UCP2 and altered mitochondrial function for the pathophysiology of hepaticencephalopathy. Fourth，we will assessthe possiblepharmocological substances on the UCP2 and mitochondrial function, as well as the locomotion behavioral activities during the hepatic encephalopathy model. Thhe aim is to promote the advances in understanding the molecular and cell biology of mitochondria in the hepatic encephalopathy, and to lead to novel approaches for the prevention and treatment of such severe disease.