RESUMO
OBJECTIVE: To investigate the effects of salvianolic acid B (SA-B) on cardiovascular endothelial cell function and platelet activation during myocardial ischemia-reperfusion in rabbits. METHODS: A total of 24 New Zealand white rabbits were randomly divided into sham-operated group, ischemia-reperfusion group (untreated group) and SA-B group. The hearts of rabbits in untreated group and SA-B group underwent half an hour of left anterior descending coronary artery (LADCA) occlusion via ligation technology, which was followed by 4 hours of reperfusion to prepared ischemia-reperfusion injury model in vivo. For sham-operated group, the animals were not subjected to occlusion of LADCA. In SA-B treatment group the rabbits were intravenously administered SA-B immediately after LADCA occlusion, and the other two groups were given normal saline in the same way instead of SA-B. The jugular vein bloods of animals were collected before LADCA ligation, half an hour after ligation and after 1-, 4-hour reperfusion, respectively. The content of plasma nitric oxide (NO) was determined by nitrate reductase process. Radioimmunoassay was applied to detect the endothelin (ET) content in plasma and the count of alpha-granule membrane protein-140 (GMP-140) on platelet surface to identify the activation of the platelet. RESULTS: No significant difference was observed before and after sham LADCA occlusion in sham-operated group in the contents of NO and ET in plasma (P>0.05), neither was the count of GMP-140 on platelet surface (P>0.05). The content of NO in plasma detected 0.5 h after LADCA occlusion was significantly decreased in untreated group compared with the sham-operated group at the corresponding time, and they were also much lower than that before LADCA occlusion in the sham-operated group (P<0.05). The plasma content of NO in untreated group showed a progressive decrease in response to the myocardial reperfusion. However, the content of ET in plasma and the count of GMP-140 on platelet surface were remarkably increased after myocardial ischemia as compared with those before LADCA ligation and those detected in sham-operated group (P<0.05). The content of ET and the count of GMP-140 in the untreated group were further increased corresponding to the aggressive reperfusion. The content of NO was significantly increased while the content of ET and the count of GMP-140 were both significantly decreased in SA-B group as compared with untreated group after 1- and 4-hour myocardial reperfusion, respectively (P<0.01). CONCLUSION: The results show that endothelial dysfunction and platelet activation occur during ischemia-reperfusion in rabbit hearts in vivo and SA-B protects cardiovascular endothelium cells against ischemia-reperfusion injury and inhibits the activation of platelet during myocardial ischemia and reperfusion.