Effect of emodin on extracellular release of HMGB1 and its mechanism

Objective To study the effect of emodin on extracellular release of high mobility group box 1(HMGB1)from endotoxin-stimulated macrophages and its mechanism.Methods The effect of emodin was investigated on HMGB1 release,expression of HMGB1 mRNA and nuclear HMGB1 translocation using cultured macrophage-like RAW 264.7 cells after stimulation with LPS,and on serum HMGB1 level and survival rate of endotoxemia mice.The levels of HMGB1 in the culture medium or serum were determined by Western blot analysis.Results Emodin dose-dependently attenuated LPS-induced HMGB1 release from macrophage-like RAW 264.7 cells,suppressed the expression of HMGB1 mRNA and HMGB1 translocation from nuclear to cytoplasm,decreased serum HMGB1 level of endotoxemia mice,and elevated the survival rate from 35% to 55% on the 96th hour after LPS was injected in mice.Conclusion Emodin inhibits the extracellular release of HMGB1 from LPS-stimulated macrophages.