To study the effects of indomethacin on interleukin-6 (IL-6) expression stimulated with lipopolysaccharide (LPS) in rheumatoid arthritic patients' synoviocyte.
Fibroblast-like cells (FLS) from rheumatoid arthritic patients' joint tissue were cultured for 24 h and incubated 24 h with LPS (1 mg.L-1) or the supernatant of U937 cells stimulated by LPS (1 mg.L-1). After indomethacin or dexamethasone added into the supernatant of U937 cells, FLS was incubated with the super natant for 24 h. The expression of IL-6 protein was detected by radioimmunoassay. The mRNA expression of IL-6 was accessed by RT-PCR.
LPS did not obviously affect the growth of FLS, and the protein secretion and mRNA expression of IL-6 were not changed in FLS treated with LPS. The IL-6 secretion and IL-6 mRNA expression were significantly increased in FLS cultured with the supernatant from U937 cell treated with LPS. Indomethacin at concentrations of 1 x 10(-7)-1 x 10(-5) mol.L-1 obviously inhibited the protein secretion and mRNA expression of IL-6 in FLS cultured with the supernatant from U937 cell stimulated with LPS, and the inhibitory effects increased as the concentrations of indomethacin increased.
Indomethacin can inhibit the increase of IL-6 expression caused by supernatant of U937 cells stimulated with LPS in FLS.