RESUMO
OBJECTIVE: To investigate HMGB-1 expression and its extracellular release of cultured primary hepatic parenchymal cells (HC) and Kupffer cells (KC) that were induced by lipopolysaccharides (LPS). METHODS: Primary hepatic parenchymal cells and Kupffer cells were cultured in flasks, and some cells were treated with 500 microg/L LPS for 24 hours (induced group) and some were not treated with LPS and served as controls. All of the cells were repeatedly frozen-thawed, and the expression levels of HMGB1-mRNA and HMGB1 proteins were detected by semi-quantitative RT-PCR and Western blot respectively. Then HC and KC were subcultured in 24-well culture plates for 6 h, 12 h, 24 h and 48 h, and the HMGB1 protein in culture fluids was detected by Western blot at each time point. RESULTS: Compared with the cells in the control group, the expression levels of HMGB1-mRNA in the induced group were significantly increased in both HC and KC at 24 h (t=31.32 and 45.90, P<0.05) and the protein levels of HMGB1 showed the same results (t=46.19 and 38.44, P<0.05). There was a small quantity of HMGB1 protein in the culture fluids of two control groups and the induced group of HC. However the HMGB1 protein in the induced group of KC were obviously increased with prolonged culture time (F=42.74, P<0.05). Compared with the control group, the level of HMGB1 protein in the induced group of KC was not increased at 6 h (t=9.57, P>0.05) but was significantly increased at 12 h, 24 h and 48 h (t=21.95, 32.39, 44.16, respectively P<0.05). CONCLUSION: LPS could increase HMGB1 expression of HC and KC and HMGB1 release from KC, but not from HC. The results suggest that KC play an important role in triggering inflammation and liver injury.