OBJECTIVETo investigate the expression of high mobility group box 1 (HMGB1) in gingival tissues of chronic periodontitis.

METHODSHuman peripheral blood mononuclear cells(PBMC) were stimulated with 1 microg x mL(-1) lipopolysaccharide (LPS) for 24 h or 48 h. Expression and release of HMGB1 were checked by immunofluorescence and enzyme-linked immunosorbent assay (ELISA), respectively. PBMC were stimulated with 100 ng x mL(-1) HMGB1 or 50 ng x mL(-1) tumor necrosis factor-alpha (TNF-alpha), the expressions of TNF-alpha and HMGB1 in the supernatant were studied by ELISA. Gingival tissues and gingival crevicular fluids (GCF) were collected from patients and healthy people. Expression of HMGB1 in gingival tissues and GCF was studied using immunofluorescence and ELISA, respectively.

RESULTSHMGB1 was translocated from nucleus to cytosol in PBMC after LPS stimulation for 24 h. The content of HMGB1 in the supernatant from stimulated cells was significantly higher than that from unstimulated cells after 48 h (P < 0.01). HMGB1 was released by PBMC in response to TNF-alpha stimulation, it also stimulated PBMC to release TNF-alpha (P < 0.01). Translocation of HMGB1 from nucleus to cytosol was also found in infiltrated cells in gingival tissues from patients, and HMGB1 in GCF from patients was significantly higher than that from healthy people P < 0.01).

CONCLUSIONThe results suggest that HMGB1 may play an important role in the pathological progress of chronic periodontitis.