The Role Of Artesunate To Prevent And Treat Escherichia Coli Bacterial Sepsis Model Mice

Objective:Sepsis,with high mortality,is systemic inflammatory response syndrome (SIRS) that results from a severe and damaging host response to infection.It is triggered by bacteria and bacterial components,such as bacterial DNA(bDNA) and lipopolysaccharide (LPS[endotoxin]).Despite better supportive care,the hospital mortality(50%to 60%) from severe sepsis and septic shock has not changed significantly over the recent decades.It is urgent to study the mechanism of SIRS and to find methods to prevent and treat SIRS.Artesunate is an effective drug for the treatment of malaria for more than 10 years. Except the effect against severe malaria,artesunate also has other uses such as anti-tummor. In previous work,we found artemisinin-mediated protection of lethal challenge by CpG DNA,LPS,and heat-killed E.coli was associated with the reduction of proinflammatory cytokine release and NF-κB activation.However,artemisinin cannot be dissolved in water, and only be taken orally,which is not suitable for serious sepsis patients.Artesunate(AS) is a derivetive of artemisinin;its anti-malaria effect is stronger than artemisinin.It can be given orally,intramuscularly,intravenously,and so on.With these considerations in mind,we undertook the current study to investigate the protection of artesunate on mice challenged by heat-killed E.coli and its possible molecular mechanisms in vitro and in vivo.Methods:①Establishing murine sepsis models firstly,then protection of artesunate on mice challenged by heat-killed E.coli was observed.②The effects of artesunate on serum endotoxin and serum TNF-αlevels in mice challenged with sublethal heat-killed E. coli were observed.③Effect of artesunate on TNF-αand IL-6 release from the murine peritoneal macrophages(PMφ) induced by heat-killed E.coli,LPS or CpG ODN 1826 were observed.;④Effect of artesunate on TLR4 mRNA expression and TLR9 mRNA expression in RAW264.7 cells stimulated by heat killed E.coli,LPS and CpG ODN 1826 were observed.Results:①Artesunate(5,15,45 mg/kg,im) delayed the death of mice challenged with heat-killed E.coli.The mortality decreased from 100%to 62.5%(p＜0.05).②Artesunate(5,15,45 mg/kg) could decrease the serum LPS and serum TNF-αlevels in mice injected with sublethal doses of heat-killed E.coli.③In vitro,artesunate potently inhibited TNF-αand IL-6 release from PMφinduced by heat-killed E.coli,LPS and CpG ODN 1826 in a dose-dependent manner.④Artesunate reduced the TLR4 mRNA and TLR9 mRNA expression in RAW264.7 cells stimulated by heat-killed E.coli,LPS and CpG ODN 1826.Conclusions:Artesunate-mediated protection of lethal challenge by heat-killed E.coli was associated with the inhibition of TLR4 mRNA and TLR9 mRNA expression and reduction of cytokines release.