The effects and mechanism of lipopolysaccharide pretreatment on endotoxemia in rats

Objective To investigate the effects and mechanism of lipopolysaccharide(LPS) pretreatment on endotoxemia in rats.Methods Male Wistar rats were randomly divided into three groups: saline group(N,n=24),LPS-treated group(L,n=24),and LPS-pretreated group(P,n=24).Intrapreitoneal injection of LPS was given to rats in Group P at baseline and 24th hour,while NS were given to rats in Group N and Group L instead.Intravenous injections of LPS were given to rats in Group L and P for construction of endotoxemia,while NS was given to Group N.The hemodynamics was observed constantly.TNF-α and NO levels were analyzed 2,4 and 6 hours after modeling.The lung,heart,liver,kidney and small intestine tissues were stained with hemotoxylin and eosin for observation.Results The pretreatment of LPS significantly reversed the endotoxemia-induced hemodynamic change(P0.05).Significantly elevation of TNF-α and NO were revealed in Group L,when comparing with those in Group N,which were significantly attenuated by pretreatment of LPS in Group P(P0.05).Moreover,significant alleviation in LPS-induced pathological impairment in heart,lung,liver,kidney and intestine were also observed in Group P.Conclusion Pretreatment of small dose of LPS protects rats from endotoxemia via reduction of TNF-α and NO.