| Chronic liver diseases are histopathologically characterized by hepatocyte fatty change, necrosis and fibrosis. Liver fibrosis which reduces liver function and life qualities of patients can not be reversed once it has been formed, Therefore, the strategies for curing chronic liver diseases are both inhibiton of fibrosis and augment of hepatocyte regeneration. Hepatocyte growth factor (HGF) is a multifunctional factor with the characteristics of augmenting liver regeneration, inhibiting fibrosis and stimulating the hepatocytic differentiation of stem cells. Bone marrow-derived stem cells which could differentiate into or fuse with hepatocytes have been applied in the liver regeneration and tissue repair. We evaluated the therapeutic effects of bone marrow-derived MSCs modified with HGF gene on chronic liver injury caused by carbon tetrachloride (CC14). And this research will provide the experimental foundations for clinical treatment of organ or tissue injury by gene modified bone marrow-derived stem cells.Bone marrow is a resource of adult stem cells consisting of hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs). We generated and expanded the adenovirus carrying GFP gene (Ad-GFP). The mesenchymal stem cells were isolated from bone marrow and the CD34+ cells were isolated from cord blood. The Ad-GFP infection efficiencies of bone marrow-derived MSCs and cord blood-derived CD34+ cells were detected by FACS. It showed that the infection efficiency of MSCs achieved 98.38% while that of HSC only 13.55% at the MOI of 150. The Ad-GFP infection efficiencies of leukemia cell lines were also very low. The adenovirus infection of cells was mediated by the cell surface expression of coxsackievirus and adenovirus receptor (CAR), the specific receptor for adenovirus. The expression of CAR by MSCs andHSCs were determined by using RT-PCR. MSCs express high level of CAR while HSCs have a low level. These results suggest that adenoviral infection efficincies of MSCs and HSCs depend on their expression of CAR. The mesenchymal stem cells were chosen as target cells for carrying the HGF gene in the treatment of chronic liver injure as their hepatocytic differentiation potential and high adenoviral infection effeciecy. We isolated and expanded the male bone marrow-derived mesenchymal stem cells and infected these cells with adenovirus carrying HGF gene (Ad-HGF). To determine whether the mesenchymal stem cells were able to release soluble HGF protein, we collected condition medium from cultured mesenchymal stem cells transfected with Ad-HGF , and assayed for HGF by ELISA. A peak of 128 ng/ml HGF was detected on day 2 post transfection. And adenovirus-mediated expressions of HGF by mesenchymal stem cells could maintain at least for two weeksTo evaluate the therapeutic effects of HGF modified MSCs on the choronic liver injure, we established a rat chronic liver injury model in which the female Wistar rats were i.p. injected with 50% CC14 and male HGF gene modified MSCs were transplanted. The therapeutic effects of HGF gene modified MSCs on the chronic liver injure were evaluated by liver histopathological changes and liver fuction after 5 weeks. The livers of model group were superficially coarse and lackluster and the brims of the lobes became blunt. Some brinks of lobes of MSC group and HGF gene modified MSC group also turned obtuse. The results of liver function showed that CC14 significantly increased the enzyme activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in blood serum of model group, while that of MSC transfected with HGF gene group had no significant difference with control. The serum AST and ALT of MSC group decreased, but significantly more elevated when compared with control rats. The liver slices showed that collagen synthesis was increased, hepatic lobule was destroyed and pseudo lobule had been established in model group. We observed that the collagen synthesis in the MSC modified with HGF gene group wasdistinctly decreased than that of model and no pseudo lobul...
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