Objective:To investigate the effects and mechanism of hemeoxygenase-1(HO-1) on acute liver transplantation rejection model. Methods:36 male DA rats used as donors were randomly divided into 3 groups:Group A was injected via vena dorsalis penis with 0.9%NaCl(5 ml/kg);Group B was injected via vena dorsalis penis with cobalt-protoporphyrin(CoPP) 5 ml/kg,hemeoxygenase-1 inducer;and Group C was injected via vena dorsalis penis with zinc-protoporphyrin(ZnPP) (5 ml/kg),hemeoxygenase-1 inhibitor,before livers were harvested. After transplantation,recipients were given the above treatments daily. Six recipients in each group underwent collection of blood and liver tissues 7 days after transplantation to detect the changes of serum enzymes[alanine aminotransferase(ALT),total bilirubin(TBIL)] and the grafts histology. The mRNA and protein expressions of HO-1 and Foxp3 in the transplanted livers were detected by RT-PCR. The other 6 recipients in each group were used to observe the survival time. Results:The survival time of Group B[(29.83 ± 1.40)d] was significantly longer than that of Group A[(13.00 ± 0.52)d,P < 0.01] and Group C[(11.67 ± 0.42)d,P < 0.01]. The values of ALT and TBIL of Group B were significantly lower than those of Group A and C(all P < 0.01). The histological manifestation of the grafts rejection in group A and C were more severe than group B. The expressions of HO-1 mRNA,Foxp3 mRNA in the transplanted livers of Group B were significantly higher than those of Group A. Both mRNA and protein expressions of HO-1 and Foxp3 of Group C were not significantly different from those of Group A. Conclusion:Continuous expression of HO-1 alleviated the reaction of acute rejection in liver transplantation. This effect partly depends on HO-1-mediated Foxp3 activation.