大鼠移植肝再灌注损伤过程中肝细胞凋亡及其调控基因表达变化

Hepatocyte apoptosis and expression of apoptosis-regulating genes during cold preservation and reperfusion injury in rat donor liver

目的研究移植肝缺血冷保存再灌流损伤过程中肝细胞凋亡变化情况及凋亡调控基因Bcl-2,FasL的表达变化。方法将72只SD大鼠分为假手术组及移植组,移植组建立原位肝移植模型,以4℃乳酸林格氏液为基液对供肝灌注并冷保存4h后置入受体,于移植后1,6,24h处死大鼠取样,检测血清中AST、ALT水平,采用TUNEL法检测移植肝肝细胞凋亡情况,流式细胞仪检测凋亡相关基因Bcl-2,FasL蛋白的表达。结果再灌注后移植组AST、ALT显著高于假手术组。与假手术组相比,移植组各时点肝细胞凋亡指数明显升高,肝组织中Bcl-2表达减少,FasL表达量增加(P<0.01),以再灌注后6h变化最为显著。结论移植术后移植肝缺血-再灌注损伤过程中肝细胞凋亡加重,于再灌注早期达到高峰,这可能与抗凋亡基因Bcl-2的表达减少,促凋亡基因FasL表达增加有关。

Objective To investigate the apoptosis of hepatocytes and the expression of apoptosis-regulating genes during the donor liver ischemia and reperfusion injury in rat orthotopic liver transplantation （OLT）. Methods Seventy-two male SD rats were randomly divided into sham operation group and transplantation group. Using Ringer＇s lactate solution as the perfusing and preserving solution, the grafts were preserved for 4 h before orthotopic transplantation. At 1, 6 and 24 h after the reperfusion, the recipients were sacrificed, and the serum ALT and AST levels were measured; the changes of hepatocyte apoptosis was detected by TUNEL assay, and the protein expressions of the apoptosis-regulating genes were measured by flow cytometry. Results Serum ALT and AST levels were significantly higher in transplantation group than in the control group after reperfusion. In comparison with the control group, the rats in the transplantation group showed significantly increased apoptosis index in the livers, lowered Bcl-2 levels and increased FasL levels after the transplantation, especially at 6 h after liver reperfusion （P0.01）. Conclusion The donor liver ischemia and reperfusion injury can promote hepatocyte apoptosis, which may be related with the high expression of Bcl-2 gene and low expression of FasL after reperfusion injury in rats with orthotopic liver transplantation.