Effects of Panax notoginseng saponins on myocardial Gsα mRNA expression and ATPase activity after severe scald in rats

Abstract

The aim of this study was to investigate the changes of myocardial Gsα mRNA expression and ATPase and the effects of Panax notoginseng saponins (PNS) on that after burns in rats. Wistar rats were exposed to a 95 °C water bath for 10 s to produce 30% TBSA skin-full-thickness scalds. Myocardial Gsα mRNA level, cAMP content and adenyl cyclase (AC) activities were determined with dot blotting hybridization, radioimmunoassay and indirect method, respectively. The ATPase activities in plasma membrane of cardiomyocytes and erythrocytes were measured colorimetrically. At 3, 6, 9 hours after scalds, the myocardial Gsα mRNA expression decreased significantly ( P<0.01). PNS (100, 200 mg kg −1, i.p.) markedly increased these levels ( P<0.01). The elevation was correlated significantly with PNS dose ( r=0.95, P<0.05). At 3, 6, 9, 12, 24, 48 hour after the scalds, the myocardial cAMP content and AC basal activity was reduced significantly. PNS (100, 200 mg kg −1, i.p.) increased cAMP content and enhanced AC activity markedly in comparison with the 3rd hour postburn group. The activities of (Ca 2+–Mg 2+)-ATPase and (Na +–K +)-ATPase in plasma membrane of myocardial cells and red blood cells in scald group were significantly lower than those in the normal control group ( P<0.01). PNS (100 mg kg −1, i.p.) improved these indexes significantly after scalds ( P<0.01 or 0.05). These data suggested that the effects of PNS on myocardium in burned rats involved its action to increase myocardial Gsα mRNA expression and AC activity, cAMP content as well as ATPase activities.