利用干细胞移植建立人鼠嵌合肝被认为是模拟人乙肝病毒（HBV）自然感染极具前景的动物模型。课题组前期利用具有免疫耐受和无排异反应的人骨髓间充质干细胞（hBMSC）移植成功救治暴发性肝衰竭（FHF）猪和大鼠，且动物肝内大量人源肝细胞均表达HBV感染特异性受体NTCP，显示含hBMSC来源肝细胞的人鼠嵌合肝具有被HBV感染的潜能。本研究拟在前期研究基础上经尾静脉注射HBV，建立新型人肝嵌合的免疫健全SD大鼠HBV感染模型；利用该模型新分泌HBV颗粒进行再感染评价；经组织学、血清学、基因组和蛋白组学等观察模型大鼠对HBV的易感性及肝损伤过程，鉴定模型动物肝细胞中Dane颗粒和NTCP、乙肝三系、HBV DNA和cccDNA等表达，发现易感HBV人源肝细胞的特异性分子，阐明HBV自然感染hBMSC/SD大鼠的确切机制。为最终阐明HBV生物学特性、乙肝发病机制、研发和筛选抗HBV新药等提供保障。

Hepatitis B virus (HBV) infection is one of the most prevalent infectious diseases associated with various liver diseases, including acute, chronic and fulminant hepatitis, hepatic cirrhosis and end-stage hepatic failure. Although the availability of HBV vaccine and the development of antiviral treatments, there are still more than 350 million people worldwide chronically infected with HBV. To clarify the precise mechanisms of HBV infection, viral life cycle, persistence of infection, and associated carcinogenesis, adequate animal models that recapitulate HBV-related liver diseases are urgently required. It is difficult to establish animal models of HBV infection because HBV has a very narrow host range and exclusively infects humans. Except of chimpanzees, tupaia, and the Asian tree shrew, no other immunocompetent animals have been used to recapitulate natural HBV infection in humans. Establish a chimeric rat model of HBV infection with stem cells transplantation has been recognized a promising alternative to overcome the limits of chimeric mouse models (need human hepatocytes as transplanted cell resources, mice do not recapitulate natural HBV infection). Our previous study has demonstrated that intraportal transplantation of human bone marrow mesenchymal stem cells (hBMSCs), which were immunological tolerant and no rejection, could rescue fulminant hepatic failure pigs and rats. The implanted hBMSCs could efficiently transdifferentiate into functional hepatocytes expressing HBV infection-specific receptor sodium-taurocholate cotransporting polypeptide (NTCP). These results imply that hBMSC-derived hepatocytes in chimeric rats may susceptible to HBV infection. Based on above results, we want to develop a novel immunocompetent hBMSC/SD rat model for HBV infection using hBMSCs transplantation in a FHF SD rat induced by D-galactosamine. The liver injury, HBV susceptibility, and re-infection process of HBV infected hBMSC/SD rat model will be evaluated by immunohistochemistry, serology, genome, proteome and metabolomics analyses. Electronic microscopy, qPCR, ELISA, and immunohistochemistry will be performed to characterize HBV DNA, cccDNA, and NTCP expression, as well as HBV Dane’s particles. We also want to discover some specific molecular and to clarify the precise mechanism of HBV infection in hBMSC-derived hepatocytes through above analysis. The final results will be helpful to elucidate the complex molecular mechanisms of HBV infection, and understand HBV biological characteristics, and discover new treatment strategies of HBV- associated liver diseases.