Abstract: Objective To explore the effect of 4 hours cold ischemic injury on allograft arteriosclerosis by means of the rat abdominal aort ic allograft model.Methods Inbred male Wistar rats served as donors and Sprague dawley(SD)male rats as recipients.They were divided into groups of immune tolerance,immune tolerance with cold ischemia,isograft with cold ischemia.The isograft abdominal aortic allograft model was setup.The specimens were treated first and the M asso n staining was then taken to obser ve fibrosclerosis degree and morphology and distribution of smooth muscle cells(VSMC)in the vessels.Immunohistochemistry was used to compare of A-actin,PCNA,CDKI,and CyclinB₁ expression in proliferating VSMC of intima and adventitia during different times postoperatively.Results Both cold ischemic groups showed significantly intimal hyperplysia appearing mainly in VSM C,proliferation and fibrosclerosis in intima and adventitia.The A-actin,PCNA,CDK1 and CyclinB1 expressed highly in proliferative VSMC and the expressions remarkedly increased with the times and allograftarter iosclero sisc progression.Conclusion Fourhours cold ischemic injury can lead to transplant arteriosclerosis.