Abstract： Objective To search the way of prolonging xenograft survival of discordant cardiac xenotransplantation.Methods All animals were divided into groups A,B,C and D receiving the following combined therapies respectively:cobra venom factor (CVF) in group A,CVF and pentoxifylline (FTX) in group B,CVF and CCS (CsA,CTX,MP)in group C,CVF,PTX and CCS in group D.The recipients were given CVF 150 μg/kg(i.P) twice daily 1,4 days before transplantation;PTX 50 mg/kg daily(i.P)1 h before transplamtation,then 25 mg/kg(i.P)in an interval of 6 h until rejection thereafter;CsA 10mg/kg(i.p) daily one day and 1 h before transplantation until rejection;CTX 40 mg/kg(i.p) one day before transplantation,then 10 mg/kg(i.P)daily 1 h before transplantation until rejection thereafter;MP 10 mg/kg(i.v)1 h before transplantation,then 1 mg/kg(i.m) daily until rejection thereafter.The expression of vascular cell adhesion molecular-1 (VCAM-1) of vascular endothelial cells (EC) in cardiac xenografts was detected by using immunohistochemical staining method.Results The mean survival time of cardiac xenografts was 57.5 h (group A),77.38 h(group B),79.13 h (group C) and 98.75 h(group D),respectively.Twenty-four h after transplantation.VCAM-1 expression in the groups B and D was not upregulated,but slightly up-regulated in group C and obvious in group A.At rejection,the up-regulation of VCAM-1 expression was mildest in group D and most obvious in group A.and VCAM-1 expression in group B was milder than that in group C (P＜0.05).Conclusions CVF combined with PTX and CCS could significantly prolong the survival time of cardiac xenograft.PTX mainly protected EC and CCS mainly inhibit inflammatory cell infiltration.Combined use of them could complement and reinforce mutually.