High mobility group box 1 (HMGB1) has been widely reported to mediate damage caused by inflammatory responses. The aim of our study is to investigate the role of HMGB1 in endotoxin tolerance (ET) alleviating inflammation of acute liver failure (ALF) rats and its possible signaling mechanism. To mimic ET, male Sprague-Dawley rats were pretreated with low dose of lipopolysaccharide (LPS) (0.1 mg/kg once a day intraperitoneally for consecutive five days) before subsequent ALF induction. ALF was induced by intraperitoneal administration of D-GalN/LPS. ET induced by LPS pretreatment significantly improved the survival rate of ALF rats. Moreover, after ALF induction, ET+ALF rats exhibited lower serum enzyme (ALT, AST and TBiL) levels, lower production of inflammatory cytokines (IL-6, TNF-a and HMGB1) and more minor liver histopathological damage than ALF rats. ET+ALF rats showed enhanced expression levels of HMGB1, decreased levels of STAT1 and p-STAT1, augmented expression of SOCS1 in liver tissues than ALF rats. These results indicated that ET induced by low-dose LPS pretreatment may alleviate inflammation and liver injury in experimental acute liver failure rats mainly through inhibition of hepatic HMGB1 translocation and release.
Keywords: Endotoxin tolerance; JAK/STAT1 signaling; acute liver failure; high mobility group box 1; lipopolysaccharide (LPS).