Effects Of Lidocaine On Expression Of High Mobility Group Box-1 Protein Induced By Lipopolysaccharide In Rat Peritoneal Macrophages

Objective To investigate the effects of different concentrations of lidocaine on expression of high mobility group box-1 protein induced by lipopolysaccharide in rat peritoneal macrophages.Methods Peritoneal macrophages obtained from male Wistar rats were incubated in six-well tissue culture plates for 3～5 days before they were stimulated with LPS and treated with different concentrations of lidocaine.They were divided into 5 groups.After washing with serum-free RPMI-1640 culture medium,macrophages in control group were incubated with 2.0ml serum-free RPMI-1640 culture medium;macrophages in group LPS were incubated with 1.980ml serum-free culture medium and 20ul LPS(10ng/ul),so the final concentration of LPS was 100ng/ml;macrophages in group Lido1,Lido2 and Lido3 were incubated with 1.960ml serum-free RPMI-1640 culture medium and 20ul LPS(10ng/ul),and 20ul lidocaine of different concentrations(0.2ug/ul,2ug/ul,20ug/ul) were respectively added,so the final concentrations of lidocaine were 2ug/ml,20ug/ml, 200ug/ml and the final concentration of LPS was 100ng/ml.Then all macrophages were incubated for 24 hours.The expression of HMGB1 mRNA in macrophages were determined by RT-PCR and the concentrations of HMGB1 in the cell culture medium were determined by ELISA.Results Compared with group LPS,RT-PCR and ELISA analysis showed that the different concentrations of lidocaine could reduce the expression of HMGB1 mRNA as well as the release of HMGB1 protein in a dose-dependent manner.LPS-induced HMGB1 mRNA expression and protein release were significantly inhibited by lidocaine in group Lido2 and group Lido3 compared with group LPS and group Lido1(P＜0.01).There was no significant inhibition of the expression of HMGB1 mRNA and the release of HMGB1 protein in group Lido1(lidocaine's final concentration was 2ug/ml) compared with group LPS(P＞0.01).Conclusion Lidocaine(final concentrations were 20ug/ml and 200ug/ml) could significantly inhibite the expression of HMGB1 mRNA and the release of HMGB1 protein induced by LPS in rat peritoneal macrophages.It maybe one of the mechanisms of lidocaine's effects in inflammation.So sepsis can be improved by using lidocaine early.But the precise mechanism needs more investigation.