Lipopolysaccharide induces high mobility group box-1 protein release in peritoneal macrophages in rats

Objective To observe high mobility group box 1 protein (HMGB1) expression and release in rat peritoneal macrophages stimulated with lipopolysaccharide (LPS).Methods Peritoneal macrophages obtained from male Wistar rats were incubated for 3 days before they were stimulated with LPS.After stimulation,HMGB1 protein expression as well as release before and after stimulation was detected by immunohistochemistry.Supernatants of controls,4 h,8 h,12 h and 24 h were collected to determine the time dependent response between LPS stimulation and HMGB1 release.Results HMGB1 was expressed in nucleus and cytoplasm of rat peritoneal macrophages.LPS stimulation could markedly enhance the HMGB1 expression and release.LPS induced HMGB1 release in rat peritoneal macrophages,peaking at 8 12 h (optical density values of normal controls vs.12 h: 19.399± 1.488 vs. 59.561± 2.991, P 0.01) and decreasing 24 h later (optical density value: 26.104± 2.671). Conclusion HMGB1 exists in nucleus and cytoplasm of rat peritoneal macrophages,which can release extracellularly by LPS stimulation.