Abstract: AIM:To investigate the early antagonism of beraprost sodium (BPS) preconditioning on ischemic/reperfusion (I/R) injury in rabbit myocardium. METHODS: Thirty-six Japanese white rabbits were randomized into three groups: (A) sham operation group (thoracotomy and threading around left coronary artery without ligation), observation for 130 min, (B) I/R group (thoracotomy with left coronary artery ligation for 40 min and reperfusion for 90 min) and (C) BPS pretreatment group (BPS, 15 μg/kg, twice a day for 4 weeks, I/R within 3 h after the last administration). Group B and group C underwent the same time length of ischemia/reperfusion. After 90 min reperfusion, six rabbits were randomly selected for HE coloration and immunohistochemical detection of Bax and Bcl-2. After 4 h reperfusion, CK-MB in plasma was detected. RESULTS: HE stain showed that the myocardial structure was normal in group A, severely injured in group B and mildly in group C. Immunohistochemical stain showed that the expression of Bax was negative, whereas Bcl-2 was positive in group A. Bax was positive, whereas Bcl-2 was weakly positive in group B. Bax was weakly positive, whereas Bcl-2 was between that in group A and group B. There was an increase in CK. Group B>group C>group A. CONCLUSION: BPS may provide some early antagonism on ischemic/reperfusion injury in rabbit myocardium in vivo.