RESUMEN
<p><b>OBJECTIVE</b>To study the effects of Tongxinluo ultramicro-pulverization (TXLU) on experimental myocardial infarction and platelet aggregation of rats, investigate its mechanisms on ischemia heart disease and offer a reference to clinical usage.</p><p><b>METHOD</b>Rats were separated randomly into 7 groups: sham, model, diltiazem (0.15 mg x kg(-1)), TXL(1.2 g x kg(-1)), TXLU (1.2, 0.6, 0.3 g x kg(-1)). The experimental myocardial infarction was induced with ligating the left anterior descending branch of the coronary of rats. The infarction size was determined after myocardium tissue was stained with 2,3,5-triphenyltetrazolium chloride (TTC). And the serum of rats was separated to analyze CK, LDH, SOD, MDA. Another 60 rats were separated randomly into 6 groups: control, aspirin (0.15 mg x kg(-1)), TXL (1.2 g x kg(-1)), TXLU (1.2 ,0.6,0.3 g x kg(-1)). The rat platelet aggregation was induced with adenosine diphosphate (ADP) and collagen to observe the inhibitory effects of TXLU.</p><p><b>RESULT</b>TXLU could relieve the myocardial infarction size and weight stained with TTC significantly, the myocardial infarction size of the three groups of TXLU were (2.7 +/- 2.1)%, (3.4 +/- 1.2)%, (2.8 +/- 1.8)%, compared with model group (8.9 +/- 5.9)%, P < 0.05 or P < 0.01. The myocardial infarction weight of the three groups of TXLU were (8.4 +/- 3.5)%, (8.7 +/- 4.1)%, (9.7 +/- 4.1)%, compared with model group (l2.2 +/- 3.6)% P < 0.05 or P < 0. 01. And the content of MDA and the activities of CK and LDH in rats subjected with ligation of coronary artery were inhibited obviously too, compared with model group P < 0.05 or P < 0.01, then the activity of SOD increased. TXLU could inhibit the maximum percentage of rats platelet aggregation induced with ADP and collagen, the maximum percentage of platelet aggregation induced with ADP were (26.9 +/- 9.2)%, (24.4 +/- 13.4)%, (30.6 +/- 12.2)%, compared with control group (44.3 +/- 15. 7)% P < 0.05 or P < 0.01; The maximum percentage of platelet aggregation induced with collagen were (33.8 +/- 6.9)%, (32.1 +/- 8.3)%, (41.5 +/- 7.8)%, compared with control group (49.2 +/- 15.9)%, P < 0.05 or P < 0.01.</p><p><b>CONCLUSION</b>The experiment results indicated that TXLU could protect myocardial tissue of rats from ischemic injury and the mechanism may be related with antioxidation and inhibiting platelet aggregation, and the results also suggested TXLU could lower clinical dosage.</p>