Abstract: To establish the model of acute vascular rejection in heart xenotransplantation,the Guinea pigs and SD rats were served as donors and recipients respectively. Heart from the donor was transplanted heterotopically into the recipient，the aorta of the donor heart was anastomosed end-to-side to the abdominal aorta of the recipient and the pulmonary artery was anastomosed end-to-side to the inferior vena cava. To prevent hyperacute rejection,Cobra venom factor （CVF） was given intravenously at a dosage of 60U·kg^-1 preoperatively，same dosage was given by an i. p. injection per 8 hours postoperatively. To prevent cellular rejection, FK506 was given at a dosage of 0.25mg·kg^-1·6h^-1 by an i. p. injection per 6 hours postoperatively. 18 operations of transplantation were done with the successful rate of 88.9%，the mean survival time of the xenografts was 24±3.05 hours. The histopathology of the rejected xenografts showed diffuse in-travascular thrombosis, interstitial hemorrhage associated with a large number of infiltrated inflammatory cells, focal ischemic infarcts and coagulative necrosis,consisted with the histological description of the acute vascular rejection reported by others. We could draw the conclusion that the guinea pig-to-rat heart transplantation model could be performed without microscope,its simplicity, easiness and reliability suggest that it is a good model in studying acute vascular rejection in heart xenotransplantation.

Key words: Xenotransplantation, Heart transplantation, Acute vascular rejection