Transplantation Of Endothelial Progenitor Cells And Liver Stem Cells Derived From Bone Marrow On Angiogenesis And Regeneration Of Liver Fibrosis In Rats

BackgroundLiver fibrosis is a necessary stage for chronic liver diseases and serious threat to human health. But there has been no satisfactory treatment so far.Recently, bone marrow stem cells(BMSCs) have been used to treat liver fibrosis. But the results of the research were different.Loss and destruction of functional hepatocytes is a feature of liver fibrosis. BMSCs have been shown to restore and regenerate hepatic tissue.However, the important histopathological characteristics of liver fibrosis are excessive extracellular matrix(ECM) deposition, normal liver tissue destruction, liver sinusoid constriction and microvascular occlusion. Potential problems include the low levels of engraftment and proliferation of exogenous cells in the liver parenchyma,inhibition of endogenous liver regeneration and lack of a role in promoting hepatic neovascularization.Potential problems associated with BMSCs therapy include blood flow disturbance and narrow growth space may prevent implantation, proliferation and differentiation of BMSCs in live, and BMSC transplantation alone may not efficiently degrade ECM and promote vascular reconstruction in liver.Thus, treatment of liver fibrosis with BMSCs transplantation alone may not be sufficient. Endothelial progenitor cells(EPCs), belonging to pluripotent stem cells, has been shown to possess the vascular reconstruction function. EPCs are the precursor of endothelial cells(ECs). EPCs can be mobilized from bone marrow by damage signals, migrate to injured or ischemic organs and differentiate to ECs, which participate in angiogenesis and vasculogenesis. Endothelial progenitor cells(EPCs) have been shown to play a function in angiogenesis and vasculogenesis. Recently, EPCs have been used for thetreatment of liver fibrosis/cirrhosis in rats. Several previous studies demonstrated that transplantation of bone marrow-derived EPCs have a potential role in hepatic neovascularization, endothelial/sinusoidal remodeling and increased hepatic blood flow.Thus, a combined transplantation of EPCs and bone marrow-derived liver stem cells(BDLSCs) may be more beneficial to angiogenesis and regeneration of live fibrosis in rats. This might be a promising strategy for the therapy of liver fibrosis.ObejectiveTo investigate the transplantation of endothelial progenitor cells and liver stem cells derived from bone marrow on angiogenesis and regeneration of liver fibrosis in rats.Methods1.40 Wistar rats(male, 6 weeks,200-300g)were randomly divided into 5 groups:normal control group, fibrosis group, EPCs transplantation group, BDLSCs transplantation group, EPCs+BDLSCs transplantation group, with 8 rats in each group.2.Rats in normal group were given subcutaneous injection of olive oil.The other4 groups were injected with carbon tetrachloride to establish the model of liver fibrosis in rats.EPCs transplantation group received EPCs infusion via the tail vein,BDLSCs transplantation group received BDLSCs infusion via the tail vein,and EPCs+BDLSCs transplantation group received EPCs+BDLSCs infusion via the tail vein.3.Rats were sacrificed and weighed at the end of 6 weeks,and the liver tissues were collected for detection.4.The gene expression of VEGF, EGF and HGF in liver of rats in each group was detected by RT-PCR.5.The expression of VEGF, EGF and PCNA in liver of rats in each group was detected by immunohistochemistry.6.All datas were presented as means ± standard deviation(SD) and analyzed bySPSS 17.0 statistical software. The differences between the mean values of each group were compared by the analysis of variance(ANOV), LSD or SNK method was used to compare between the two groups.and considered to be statistically significant when the adjusted P values were < 0.05.Results1.VEGF gene and protein expression in liver:the EPCs+BDLSCs transplanttation group is higher than the EPCs transplantation group and the BDLSCs transplantation group,and the EPCs transplantation group is higher than the BDLSCs transplantation group,the fibrosis group is the lowest.2.EGF gene and protein expression in liver:the EPCs+BDLSCs transplantation group is higher than the EPCs transplantation group and the BDLSCs transplantation group,and the EPCs transplantation group is higher than the BDLSCs transplantation group,the fibrosis group is the lowest.3.HGF gene and protein expression in liver:the EPCs+BDLSCs transplantation group is higher than the EPCs transplantation group and the BDLSCs transplantation group,and the EPCs transplantation group is higher than the BDLSCs transplantation group,the normal control group is the lowest.Conclusion1.The transplantation of endothelial progenitor cells and liver stem cells derived from bone marrow in pathoenvironment can increase the angiogenesis and improve the microcirculation of the liver fibrosis in rats,and superior to endothelial progenitor cells or liver stem cells alone, and the effect of the endothelial progenitor cells transplantation group is better than the liver stem cells transplantation group.2.The transplantation of endothelial progenitor cells and liver stem cells derived from bone marrow in pathoenvironment can increase the regeneration of liver cells and promote the repair of the liver fibrosis in rats,and superior to endothelial progenitor cells or liver stem cells alone,and the effect of the endothelial progenitor cells transplantation group is better than the liver stem cells transplantation group.