脂肪肝对缺血再灌注损伤(IRI)和免疫损伤更敏感。减轻IRI和免疫损伤、提高脂肪肝供肝利用率是肝移植领域的重要课题。间充质干细胞(MSC)通过组织修复、免疫调节、基因治疗等发挥损伤保护作用，但MSC在体内作用时间短影响其疗效。我们已发现①细胞防御系统中最重要的转录因子Nrf2明显减轻肝脏损伤；②MSC多途径发挥免疫调节作用；③MSC减轻脂肪肝IRI并与Nrf2上调有关；④前述研究中microRNA参与IRI及免疫调节。本课题建立大鼠脂肪肝供肝肝移植模型(模拟肝移植临床实际问题，术后早期同时发生IRI和免疫损伤)，以Nrf2为切入点，研究携带Nrf2的MSC是否延长其体内作用时间、增强其减轻IRI和免疫损伤作用，并探讨相关microRNA在MSC发挥损伤保护作用中的调控机制，旨在阐明MSC对脂肪肝供肝肝移植损伤保护作用中Nrf2的关键作用及内在机制，为肝移植IRI和免疫损伤提供新的治疗方法。

Fatty livers are more sensitive to ischemia reperfusion injury and immune injury than normal livers. Attenuation of ischemia reperfusion injury and immune injury and increasing utilization rate of donor from fatty liver is an important task in the field of liver transplantation. Mesenchymal stem cells represent a promising cell source for tissue repair and gene delivery. However, transplanted mesenchymal stem cells survive for a rather short time after in vivo implantation. Repeated infusions of mesenchymal stem cells are more effective in improving efficacy compared with single infusion. Our previous study showed that mesenchymal stem cells attenuate ischemia reperfusion injury of fatty liver in rats,and have an unique immunomodulatory property. Both of these characteristics are related to the regulatory function of microRNA. Nrf2, as one of the most important cellular protective transcription factors, demonstrates the protective effects on the liver injury. In this study, we investigate that whether mesenchymal stem cells overexpressing Nrf2 can reduce oxidative stress-induced apoptosis and cytotoxicity, prolong its survival time in vivo, and enhance their function of attenuating ischemia reperfusion injury and immune injury of fatty liver graft after liver transplantation in rats. We also investigate the regulation mechanisms of microRNA related to signaling passway of Keap1-Nrf2-ARE on mesenchymal stem cells-mediated protection from ischemia reperfusion injury and immune injury. The results of the study will not only provide a new theoretical basis for mesenchymal stem cells for treatment of ischemia reperfusion injury and immune injury in liver transplantation, but also provide a new way for attenuating hepatic ischemia reperfusion injury and immune injury after liver transplantation, and increase the successful rate of liver transplantation with fatty liver graft.