Figure 3.

The effects of signaling pathway inhibitors on leptin induced NO (a), PGE₂ (b), IL-6 (c), and IL-8 (d) production in human OA cartilage. Cartilage explants were incubated for 48 hours with leptin (10 μg/mL) and the inhibitor indicated. NO production (a) was measured as nitrite accumulation in the culture medium by Griess reaction. PGE₂ production (b) in the culture medium was measured by RIA. Levels of IL-6 (c), and IL-8 (d) in the culture medium were measured by ELISA. Leptin-induced NO/PGE₂/IL-6/IL-8 production was set as 100%, and the other values were related to that. The results are expressed as mean ± SEM. Samples were collected from 7 patients in (a) and (b) (n = 7) and from 6 patients in (c) and (d) (n = 6). ∗: P < .05, ∗ ∗: P < .01, and ∗ ∗ ∗: P < .001 as compared to explants treated with leptin alone.