Objective     To investigate the influence of proteasome inhibitor MG-132 on inflammatory factors in rat model of myocardial ischemia/reperfusion.      Methods     Adult Sprague-Dawley rats were divided into 4 groups. I/R group: left anterior descending (LAD) coronary artery was ligated for 30 min

and then reperfused for 0

1

2

6

24 h; I/R+T group: MG-132 was used for treatment

and other procedures as I/R group; Sham operation group; Sham operation+T group. At 5 min before reperfusion

MG-132 (0.75 mg/kg) was given intravenously in I/R+T group and Sham operation+T group

and normal saline for I/R group and sham operation group. The changes of myocardial ultrastructure were checked

and the protein and mRNA levels of NF-κBp65 and TNF-α

the number of PMN

the activity of MPO and survival of each group were detected.      Results     As compared with Sham operation group and Sham operation+T group

the protein and mRNA levels of NF-κBp65 and TNF-α

the number of polymorphonuclear leucocytes (PMN) and the activity of myeloperoxidase (MPO) were significantly increased in I/R group (P0.05)

and these indexes were significantly higher at 1

2

6

24 h after reperfusion than that at 0 h (P0.05). The cardiocytes diffused and swelled

the myofilament was lysed

and the mitochondria swelled and vacuolizated. The above-mentioned inflammatory factors of I/R+T group were significantly decreased as compared with I/R group (P0.05)

and could keep at a low level at least for 24 h. The damaged degree of cardiocytes in I/R+T group was less and the mortality due to deadly arrhythmia was lower than that of I/R group.      Conclusion     Myocardial reperfusion injury can be inhibited by proteasome inhibitor MG-132 through suppressing the expression of inflammatory factor in rats.