Abstract:

BACKGROUND: Previous studies have shown that tetramethylpyrazine (TMP) can decrease expression of connective tissue growth factor (CTGF), nuclear factor kappa B (NF-κB) and delay the formation of hepatic fibrosis. But the mechanism and the correlation of CTGF and NF-κB was not clear.           
OBJECTIVE: To investigate the effects of TMP on expression of CTGF, NF-κB and its related gene product interleukin-6 (IL-6) in tumor necrosis factor-alpha (TNF-α) stimulated hepatic stellate cells.
METHODS: Hepatic stellate cell-T6 (HSC-T6) was cultured to logarithmic growth phase for experiments. Cells were divided into four groups: control group: only cells were added; TNF-α group: 10 μg/L TNF-α was added; TMP intervention group: pretreated with 10 μg/L TNF-α for 30 minutes and then 50,100, 200, 400, 600, 1 000 mg/L TMP was added; PDTC group: pretreated with   10 μg/L TNF-α for 30 minutes, and then stimulated with 18 μmol/L PDTC, a blocker of NF-κB.
RESULTS AND CONCLUSIONS: MTT assay results showed that TMP inhibited the proliferation of HSC-T6 at a concentration of 100, 200, 400, 600, and 1 000 mg/L in a concentration dependent manner (P < 0.05). Immunocytochemical staining and western blot analysis showed that 200, 400, 600 mg/L TMP and 18 μmol/L PDTC could decrease the expression of TNF-α-induced CTGF, NF-κB and IL-6 (P < 0.01) in HSC-T6 cells and with increasing concentrations of TMP, the inhibitory effects were enhanced, and PDTC could inhibit their expression effectively. Correlation analysis showed that the expression of cTGF and NF-κB in HSC-T6 cells was positively correlated (r=0.980, P < 0.01).These data indicated that TMP could inhibit the expression of cTGF, NF-κB and IL-6 in hepatic stellate cells and inhibit the proliferation of hepatic stellate cells.