RESUMO
<p><b>OBJECTIVE</b>To investigate the severity of early myocardial injury in rats with 30% full thickness burn at plateau and the protective effects of Rhadiola Astragalus Codonopsis Compound (RACC) on the rat myocardial injury.</p><p><b>METHODS</b>One hundred and four Wistar rats with 30% full thickness burn were randomly divided into RACC application (R, n = 48) and scalding group 1 (S, n = 48), and another 8 healthy Wistar rats as control group 2 (C, n = 8). Four ml of RACC was garaged into the rat stomach in R and 4 ml isotonic saline in S groups respectively, but no treatment in C group. Blood samples from the aorta were harvested in 3, 6, 12, 24, 48 and 72 postburn hours (PBH) for blood gas analysis and for the determination of the changes in myocardial enzymes. Rat heart was harvested for pathomorphological examination.</p><p><b>RESULTS</b>The rat myocardial tissue injury in R and S groups was obvious at 3 PBH and ameliorated gradually thereafter, up to the degree in C group at 72 PBH. The serum levels of myocardial enzymes in R and S groups were significantly higher than those in C group (P < 0.01). Whereas the enzymes in R group were much lower than those in S group (P < 0.01). It was indicated by blood gas analysis that the pH in R and S groups was lower than that in C group (P < 0.05), while that in R group at 12 - 24 PBH was higher than that in S group (P < 0.05). In addition, the base excess in R and S groups was lower than that in C group (P < 0.01), while that in R group at 6 PBH was higher than that in S group (P < 0.05 approximately 0.01). The PaCO2 in R and S groups was evidently lower than that in C group (P < 0.05 approximately 0.01), while that in R group at 48 PBH was no different to that in C group (35.70 +/- 4.23 mmHg vs 37.50 +/- 6.53 mmHg, P > 0.05). The PaO2 in R and S groups at 3 approximately 24 PBH was higher than that in C group and decreased gradually (P > 0.05). There was no difference in SaO2 among 3 groups (P > 0.05).</p><p><b>CONCLUSION</b>RACC exhibited beneficial to the protection of rat heart from myocardial injury at plateau induced by severe burn.</p>