The expression of heat shock protein 70 and its early diagnostic significance in acute allograft rejection of liver-transplanted rats

Objective To investigate the expression and the early diagnostic significance of heat shock protein 70 in acute allograft rejection of liver-transplamed rats. Methods The model of rat orthotopic liver transplantation was made by using a modified two-cuff technique. The rats were randomly divided into 3 groups. For each group, donors and receptors all included 15 rats respectively. The control group: Wistar to Wistar liver transplantation; The untreated group: SD to Wistar liver transplantation, not receiving any immunosuppressant after liver transplantation; The treatment group: SD to Wistar liver transplantation, receiving intramuscular injection of tacrolimus (FKS06, 2mg kg-1. day-1) after operation. Five rats were executed randomly in every group on the post-transplantation day 3, 5 and 7 and the graft samples were obtained for optical microscopic observation. The expression of HSPT0 in grafts was detected by using immunohistochemical method and RT-PCR. The correlation between acute rejection following liver transplantation and the expression of HSP70 in grafted liver was studied. Results There was no acute rejection examined in the control group. The untreated group showed typical allograft rejection and the rejection activity index (RIA) went up gradually after the operation (P<0.01). The treatment group showed no rejection or borderline allograft rejection. The level of HSP70 was increased transiently after operation, then reduced in the control group (P<0.05). The level of HSP70 in the untreated group was higher than in the control groupand gradually increased with the prolongation of time after transplantation (P<0.01). A significant correlation was found between HSP70 and pathological score in the untreated group (P<0.01). The treatment group showed low levels of HSP70 of all the time. Conclusions The expression of HSP70 in grafts is closely related to the occurrence and development of the acute rejection and can be useful for early diagnosis of acute allograft rejection following liver transplantation. Key words: Heat-shock proteins 70; Liver transplantation; Graft rejection