Fig 1: MN-1 inhibits spontaneous production of tumor necrosis factor (TNF) and interleukin (IL)-1 from human rheumatoid arthritis (RA) synovial membrane cultures. Human RA synovial membrane cultures were incubated for 24 h in the presence of media alone unstimulated (US) or media containing dimethyl sulfoxide (vehicle control) or MN-1. (A) A dose response was generated using a quarter log titration of MN-1. Data are representative of 3 independent experiments from independent donors. (B) Cell viability was assessed by a 3-[4,5 dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide assay. Data are representative of 3 independent experiments from independent donors. (C) Pooled data is shown for 3–5 independent experiments from independent donors. All experiments were performed in triplicate with the average plotted from each donor. Where shown as a percentage, this was calculated from the maximal spontaneous release of TNF (n = 5) or IL-1 (n = 3) from untreated control cells. A two tailed t-test of paired data was used with a 95% confidence interval to compare cytokine release in the presence of 100 uM MN-1 compared to spontaneous cytokine release in the absence of MN-1 (***p < 0.001; **p < 0.01) for the pooled data in part C. The analysis was performed for each cytokine separately. Standard error of the mean was used for pooled experimental data, whilst standard deviation was used in graphs showing representative experiments.