Abstract:

To study the protective effect of paraxadiol saponins(PDS) on myocardium of rats with endotoxic shock and reveal the relationship between the protective effect and AQP1 expression level. Methods 40 Wistar rats were divided into 4 groups: control group(CTR),lipopolysaccharide endotoxic shock model group(LPS),dexamethasone treatment group(DEX) and PDS group. LPS (5 mg·kg-1) was administered sublingually to build up the model of endotoxic shock,the mean arterial pressure(MAP) and the decreasing percentage of MAP were monitored at different time. The contents of AST,CK and LDH in serum and SOD activity and MDA content in myocardium were detected after shock for 240 min.The AQP1 expression level in myocardium was detected with Western blotting. Results When the blood pressure fell to 2/3 of the baseline it was regarded as the start of shock. It was found by dynamic observation that the rats entered into shock state at 5 min,the MAP had an compensatory restoration at 20 min,the MAP fell progressively since 60 min until the models got close to death at 240 min in LPS group,but  the MAP remained steady and constant compensatory changes in PDS and DEX groups until the rats were sacrificed at 240 min. The serum contents of AST,CK and LDH in LPS group were highest among groups,but in PDS and DEX groups they were lower (P<0.05)；the SOD activities in PDS and DEX groups were higher than those in LPS group (P<0.05),meanwhile the contents of MDA were lower than those in LPS group(P<0.05). Western blotting result showed that the quantity of expression in LPS group was significantly lower than that in control group(P<0.05),but in PDS group and DEX group they were higher than that in LPS group(P<0.05). Conclusion PDS has the protective effect against myocardium injury in rats with endotoxic shock,the mechanism may be adopted to enhance the expression of AQP1 in capillary endothelial cells of LPS-induced endotoxic shock rats,and inhibit the myocardial stromal edema.

Key words: panaxadiol saponin;endotoxic shock;myocardium;aquaporin 1