This study aims to demonstrate that blocking the receptor-interacting protein2(Rip2)expression can decrease inflammatory cytokine production by macrophage and protect mice from endotoxin lethality.Murine Rip2 small interfering RNA(siRNA)plasmids were constructed and transfected into macrophage and Rip2 expression was detected with reverse transcription-polymerase chain reaction(RT-PCR)and weste blot.Cell proliferation was assayed with MTT.TNF-α concentration was assayed with ELISA and high-mobility group box 1 protein(HMGB1)level with semi-quantitative weste blot after lipopolysaccharide(LPS)stimulation.LPS challenge was given after the plasmids were injected into mice and the survival rate was calculated.Rip2 siRNA plasmid could block the mRNA and protein expression of Rip2 and promote cell proliferation.Blocking Rip2 could attenuate LPS-induced TNF-~ and HMGB1 production.The HMGB1 expression in the liver decreased to(40.21±11.03)pg/g,and serum TNF-α level decreased to(300.43±59.26)ng/L(P＜0.05).The survival rate of mice from endotoxemia was also improved(P＜0.05).The results demonstrate that Rip2 siRNA plasmid can block the expression of Rip2,decrease the production of TNF-α and HMGB1 and protect mice from fatal endotoxemia.