Expression of high mobility group protein B1 and Toll-like receptor 4 in liver of septic rats and their relationship

Objective To investigate the changes of high mobility group protein B1(HMGB1) and Tolllike receptor 4(TLR4) gene expression in liver of septic rats,and to elucidate the relationship between HMGB1mRNA and TLR4 mRNA expression.Methods Sepsis was induced in rats by cecal ligation puncture (CLP).Fifty Wistar rats were randomly divided into 2 groups:the normal control(n = 10) and the CLP group;the latter was further divided into 6 h,12 h,18 h,and 24 h CLP subgroups(n = 10 in each subgroup).The expression of HMGB1 mRNA and TLR4 mRNA in the liver was examined by real-time polymerase chain reaction(PCR). Results Weak expression of HMGB1 mRNA and TLR4 mRNA was observed in the liver of normal rats.The expression levels of both HMGB1 and TIR4 mRNA in the CLP group were significantly higher than those in the normal control group at all time points after operation(P0.01).The expression of HMGB1 mRNA and TLR4 mRNA increased in 6 h CLP group,peaked in 12 h CLP,and then declined gradually after 18 h,with significant differences found at all time points(P0.05).Correlation analysis showed that the expression of HMGB1 mRNA was positive correlated with TLR4 mRNA expression in the liver of septic rats(r = 0.90,P = 0.04).Conclusion HMGB1 may further activate inflammatory cells through TLR4,and result in a waterfall effect of the downstream inflammatory factors.