Abstract: Objective To observe the effects of probucol on the expression of interleukin-18 (IL-18) and oxidative stress product malondialdehyde (MDA) in rat peritoneal mesothelial cells treated with lipopolysaccharide (LPS). Methods Primary culture of rat peritoneal mesothelial cells (RPMCs) were randomly divided into 3 groups: cells growing in serum-free DMEM/F12 medium (normal control group), cells stimulated with different concentrations of LPS (1, 10 and 100mg/L) for 6h or stimulated with 10mg/L LPS for 3, 6, 12 and 24h (LPS group), and cells pretreated with probucol (20, 40 and 80μmol/L) for 1h and then stimulated with 10mg/L LPS for 11h (probucol group). IL-18 mRNA was measured by quantitative real time-PCR, IL-18 in medium was assayed by ELISA, and MDA was determined by thiobarbituric acid method. Results The expressions of IL-18 and MDA increased in RPMCs (P<0.05), and the increases were dependent on the LPS concentration used and the period of LPS stimulation lasted. The peak of IL-18 expression arrived after LPS stimulation for 12h (P<0.01). The expressions of IL-18 and MDA were significantly inhibited in probucol group (P<0.05) as compared with those in LPS group stimulated with 10mg/L LPS, and the inhibition was dependent on the probucol concentration used. Conclusions The expressions of proinflammatory cytokine IL-18 and oxidative stress product MDA were increased in RPMCs stimulated with LPS. Probucol inhibited the two changes, facilitating the repair of cell damage and the reduction of peritoneal inflammation.

Key words: Probucol, Peritoneal mesothelial cell, Interleukin-18, Malondialdehyde