Establishment Of A Mouse Model With Porcine Hepatocyte Orthotopic Repopulation

Background and Purpose:The liver plays a very important role in the human body,performing a variety of functions such as drug conversion,protein synthesis and digestion and metabolism.These functions are largely dependent on the liver cells.The liver also contains Kupffer,NK,Dendritic,NK-like T and other immune cells,which perform important immune functions.When liver disease occurs it poses a serious threat to human health.Liver failure is a common clinical condition of the liver.A variety of factors lead to widespread liver cell necrosis,which in turn leads to an imbalance in the body’s physiological metabolism.The large accumulation of associated toxic metabolites leads to further liver cell damage,which can deteriorate into liver failure if left untreated.Only in situ liver transplantation is an option for treatment.However,whole liver transplantation is costly and unaffordable,the procedure is complex and difficult to perform,there is a shortage of donor livers and the post-operative treatment is cumbersome.A new form of treatment is needed.As a special organ with the ability to regenerate,hepatocyte infusion therapy holds the promise of reversing liver failure and slowing the progression of liver disease.Hepatocyte infusion provides both a buffer period for patients waiting for a donor organ and as a primary treatment.However,most healthy livers from deceased donors are preferentially used for liver transplantation in situ.Healthy and functioning human liver cells are more difficult to obtain than whole livers.Another obstacle is that primary human hepatocytes are difficult to expand in culture in vitro.To overcome these problems the researchers set out to find a source of xenogeneic cells that could replace human liver cells.The structural,physiological and biochemical functions of porcine organs are close to those of humans and are considered to be an ideal source of xenogeneic donors.However,there are fewer studies comparing the physiological,biochemical and detoxification functions of pig hepatocytes with those of human hepatocytes.The main reason for this is the lack of suitable small animal models.Previous studies have shown that human hepatocytes can be regenerated in Fah^-/-immunodeficient mice,providing an ideal animal model for in vivo studies of human hepatocytes,which have been widely used in in vivo studies of xenogeneic hepatocyte proliferation and regeneration,treatment of various hepatophilic viruses,and various metabolic reactions.However,there are still no reports of mouse models with in vivo regeneration and chimerism of porcine hepatocytes.We initially explored the conditions associated with the transplantation and regeneration of porcine hepatocytes in the absence of T\B\NK-cell-mediated rejection by constructing a porcine-mouse liver cell chimerism model to assess the settlement,proliferation and functional factor secretion of porcine hepatocytes in xenogeneic recipients,and to improve the reconstruction efficiency of porcine hepatocytes in Porcine-derived mice model by a simple and long-lasting new method.To provide a valid animal model for in vivo comparison of the functional differences between porcine and human hepatocytes.Methods:By transplanting primary porcine hepatocytes to livers of immunodeficient mice(Fah^-/-Rag2^-/-IL2Rg^-/-)after xeno-repopulation induced by Spleen injection.Experimental group 1 was transplanted with porcine liver cells,and experimental group 2 was transplanted with porcine liver cells carrying the GFP gene.The control group was not treated with transplantation.Observe the weight change and survival status of mice in each group.At every two weeks after transplantation,the levels of porcine albumin in the serum of each group were measured by ELISA.At the tenth week after transplantation,the level of porcine hepatocyte chimerism in each group of livers was measured by immunohistochemistry.Results:After transplantation of porcine liver cells into mice,the secretion of porcine albumin in the serum of experimental group 1 mice gradually increased.At the 10th week of transplantation,porcine albumin secretion was 1.05±0.67 mg/ml.Furthermore,the repopulation rate of porcine hepatocytes was 11±4%was determined by immunochemistry FAH staining.Conclusion:The porcine hepatocytes within the chimeric liver of FRG mice can settle,expand and secrete important functional proteins in a long-term stable manner,establishing a Porcine model of chimeric liver.