ABSTRACT
<p><b>OBJECTIVE</b>To 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.</p><p><b>METHODS</b>The 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.</p><p><b>RESULTS</b>As 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).</p><p><b>CONCLUSION</b>Combined 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.</p>