OBJECTIVETo compare the protective effects of tetramethylpyrazine (TMP) alone and TMP and L-arginine (TMP-LA) combination on rats with acute myocardial infarction (AMI), and to explore its mechanism.

METHODSThe rat model of AMI was established by via caudal vein injection of pituitrin. Experimental animal groups of normal, model, TMP treated and TMP-LA (via abdominal cavity and caudal vein respectively) treated groups were established. Expression of P- and E-selectin, serum creatine phosphokinase (CK) and troponin T (TnT), and marrow peroxidase (MPO) concentration in myocardial tissue were determined by immunohistochemical stain.

RESULTSAs compared with the normal group, serum CK and TnT level, and MPO concentration in myocardial tissue were significantly higher in the model group (P < 0.01), with P- and E-selectin significantly up-regulated (P < 0.01). As compared with the model group, the above-mentioned parameters in the TMP or TMP-LA treated group was significantly lower (P < 0.05).

CONCLUSIONCombined use of TMP and LA showed obvious synergism in treating AMI, by way of multi-link inhibition on expression of adhesive factors and decrease of leucocyte infiltration.