OBJECTIVETo investigate the effect of high glucose on the expressions of toll-like receptor 4 (TLR4) and proinflammatory cytokine production induced by lipopolysaccharide (LPS) in hepatic stellate cells in vitro.

METHODSHepatic stellate cell line T6 was cultured in vitro and stimulated by high glucose. The mRNA and protein expression of TLR4 were detected by RT-PCR and Western blotting, respectively. After a 24-h pretreatment with high or low glucose, the cells were stimulated with LPS for 2 h, and Western blotting was used to detect the nuclear translocation of nuclear factor-κB (NF-κB); at 24 h of LPS exposure, the cells were examined for MCP-1 and IL-6 mRNA and protein expression levels with RT-PCR and ELISA, respectively.

RESULTSHigh glucose significantly increased the mRNA and protein expressions of TLR4 (P<0.01) in a time- and dose-dependent manner. High glucose promoted NF-κB nuclear translocation and significantly enhanced the expression and secretion of both MCP-1 and IL-6 (P<0.01). Pretreatment with high glucose significantly promoted LPS-induced NF-κB nuclear translocation (P<0.01) and the mRNA expression and secretion of MCP-1 and IL-6.

CONCLUSIONSHigh glucose can increase TLR4 mRNA and protein expressions in hepatic stellate cells and promote LPS-induced NF-κB activation and production of proinflammatory cytokines.