Objective: To investigate quantification of expression of LTB4 inducing IL-1beta and TNF-alpha at mRNA level in synovial membrane cells of rheumatoid arthritis.
Methods: Primary cultured synovial cells from RA patients were treated with exogenous LTB4, MK-886 (inhibitor of 5-lipoxygenase activating protein) and Bestatin(inhibitor of leukotriene A4 hydrolase) in the presence of LIT respectively, expressions of TNF-alpha and IL-1beta were detected at mRNA level by Real-time Quantitative PCR.
Results: Expressions of basic TNF-alpha (TNF-alpha/GAPDH) and IL-beta (IL-beta/GAPDH) at mRNA level in primary cultured synovial cells were 0.02 +/- 0.00 and 0.16 +/- 0.01 respectively. LTB4 (10(-9) mol/L-10(-8) mol/L) was shown to induce dose-dependent increase of mRNA expression of TNF-alpha. (7-15 times) and IL-1beta (1 time) , endogenous product of LTB4 by LIT significantly increased mRNA expressions of TNF-alpha (145 times) and IL-1beta (12 times) respectively. LIT-treated synoviocytes with addition of MK-886 (5-LOX exciting protein FLAP inhibitor) (1-10 micromol/L) were inhibited to secrete LTB4 dose-dependently, following the markedly down-regulated expressions of TNF-alpha (15%-66%) and IL-1beta (41%-71%) at mRNA level . Bestatin(100 mg/L) could also remarkably diminish LTB4-induced mRNA expressions of TNF-alpha(86%) and IL-1beta (79%).
Conclusion: LTB4 of synovial membrance cells in rheumatoid arthritis could induce expressions of TNF-alpha and IL-1beta at mRNA level, and their expression at mRNA level had been quantified successfully. It is a beneficial help to quantify all kinds of cytokines in methodology.