Prevention of grafted liver from reperfusive injury

Protective effects against hepatic ischemia-reperfusion injury after rat orthotopic liver transplantation because of BCL-2 overexpression

This study aims to investigate the protective effects and mechanism of recombinant adenovirus Ad.VSG-hBCL-2 towards ischemia/reperfusion injury in rat liver graft. Recombinant adenovirus Ad.VSG-hBCL-2 was injected into the donor rat liver of the experiment group through the portal vein, the laparotomy was performed for liver 36 h later, and the liver was save in lactated Ringer's solution at 4°C for 4 h, "two-cuff method" was used to perform the orthotopic liver transplantation. The bile secretion situations of two groups were observed 6 h after the portal vein reflow; the recipient rats were killed to detect the plasma levels of AST, ALT and LDH. And the expressions of Bcl-2 and TNF-α in liver tissue, and TUNEL assay was used to detect the apoptosis of liver tissue cells, electron microscopy was used to observe the changes of subcellular structures of liver tissue. 6 h after the surgery, the immunohistochemistry and Western Blot test showed that the Bcl-2 expression in the liver of the experiment group significantly increased than the control group, the bile secretion increased, the levels of AST, ALT and LDH were significantly lower, and the TNF-α expression increased significantly. The changes of cellular morphology of the experiment group were milder, and the apoptotic index was significantly lower than the control group. The portal vein-transfected recombinant adenovirus Ad.VSG-hBCL-2 could be effectively expressed in rat liver, and the high expressed Bcl-2 could reduce the ischemia/reperfusion injury in the transplanted liver.

Effect of local CTLA4Ig gene transfection on acute rejection of small bowel allografts in rats

AIM: To evaluate the local expression of CTLA4Ig gene in small bowels and its action on preventing acute rejection of the small bowel allografts.

METHODS: Wistar rats underwent heterotopic small bowel transplantation from SD rats. The recipients were divided into experimental group (allografts were transfected with CTLA4Ig gene) and control group (CTLA4Ig gene not transfected) randomly. In the experimental group, the donor small bowels were perfused in vitro with CTLA4Ig cDNA packaged with lipofectin vector via intra-superior mesenteric artery before transplantation, and the CTLA4Ig expression in the small bowel grafts post-transplantation was assessed by immunohistology. On d 3, 7 and 10 post-transplantation, the allografts in each group were harvested for the examination of histology and assay of apoptosis.

RESULTS: Small bowel allografts treated with CTLA4Ig cDNA showed abundant CTLA4Ig expression after transplantation. Acute rejection grade Ⅰ on day 7 and grade Ⅱ on day 10 after transplantation was noticed in the control allografts, and a dramatically increased number of apoptotic enterocytes in parallel to the progressive rejection could be recognized. In contrast, the allografts treated with CTLA4Ig cDNA showed nonspecific histological changes and only a few of apoptotic enterocytes were found after transplantation.

CONCLUSION: Local CTLA4Ig gene transfection of small bowel allograft is feasible, and the local CTLA4Ig expression in the allograft can prevent acute rejection after transplantation.