Differentiation of recipient bone marrow stem cells into vascular endothelial cells in rat allogenic livers

Objective To investigate the differentiation of recipient bone marrow stem cells into vascular endothelial cells in transplanted allogenic livers and the influence of its intraportal transfusion on the postoperative early reject reaction of orthotopic liver transplantation(OLT) in rats. Methods The two-cuff OLT model was performed in rats, in which female Wistar rats were used as donors and female SD rats as recipients. Recipient rats were randomly divided into 2 groups: the control group(n = 6) and the experimental group(n = 12). The former was performed orthotopic liver transplantation only,while the latter underwent intraportal transplantation of bone marrow cells (SD male, 1 × 107/mL, 0.5 mL) on the operation. Recipient rats in the experimental group were sacrificed on the 7th day(n = 4)?14th day(n = 4) and 21st day(n=4) after the end of operation, respectively, and then liver were extracted. The differentiation of recipient bone marrow stem cells into VECs in rat allogenic livers was assessed using the double staining technique combining in site hybrid histochemistry(ISHH) for rat Y-chromosome specific Sry gene-positive bone marrow stem cells with Immunohistochemistry(IHC) for von Willebrand factor (vWF). Liver pathological changes were also observed. Results The general state of health in the experimental group was much better than that in the control group. Sry region of the Y-chromosome (nuclear blue coloring) and vWF (cytoplasm brown coloring) double labeled cells appeared in the allogenic liver on the 7th day and on the liver vessel wall on the 14th day and 21st day after the liver transplantation in the experimental group. The pathologic features showed serious acute rejection in the control group, and gentle or middle acute rejection damages in the experimental group at 3rd week after the transplantation. Conclusions Recipient bone marrow stem cells can differentiate into VECs and express vWF in the liver allograft. The VECs in the transplanted liver can be partly replaced by the ones from stem cells. Intraportal transfusion of the bone marrow stem cells can alleviate acute reject reaction to the allograft.