Abstract: AIM: To observe the influence of tetramethylpyrazine on the expression of Bcl-2 and Fas proteins in myocardial injury induced by catecholamine in rats.METHODS: 36 Wistar rats were divided into 3 groups: cardiac injury group (n =12), tetramethylpyrazine treated group (n =12) and control group (n =12).The rat cardiac injury was induced by the subcutaneous injection of isoproterenol (ISO, 5 mg·kg^-1·d^-1).Bcl-2 and Fas protein was identified by immunohistochemical technique and the mean optical density (OD) values of the positive fields of protein expression were quantitatively examined by image analysis system.RESULTS: The expression of Bcl-2 protein was increased significantly in the cardiac injury group and tetramethylpyrazine treated group as compared with that of the control group (P<0.01).There were no significant difference in the Bcl-2 protein expression between the tetramethylpyrazine treated group and cardiac injury group (P >0.05), but the expression of Fas protein was decreased significantly in the tetramthylpyrazine treated group as compared with that of the cardiac injury group (P<0.05).The protein expression ratio of Bcl-2 Fas was increased significantly in the tetramethylpyrazine treated group as compared with those of the cardiac injury group and the control group.The myocardium pathological damage was decreased significantly in the tetramethylpyrazine treated group.CONCLUSION: Tetramethylpyrazine can significantly inhibit the expression of pro-apoptotic Fas protein and raise the ratio of Bcl-2 Fas protein cardiomyocytes.

Key words: tetramethylpyrazine, myocardium injury, Bcl-2, Fas, apoptosis, catecholamine