Relative SPs induction by inflammatory mediators/proinflammatory cytokines (10ng/ml tumor necrosis factor α [TNF α], 10ng/ml interleukin-1β [IL-1β]) quantified by real-time RT-PCR.

A: Analysis of human primary chondrocytes. SP-A shows upregulation only at 12h and 24h TNF α, for IL-1β at 12h and 24h, in combination (TNF α + IL-1β) for 12h and 24h. SP-B: Significant upregulation is detected with TNF α for 24h and 72h and in combination with IL-1β for 12h and 72h. SP-C: Almost continuous stimulation time-dependent upregulation from 6h to 24h. Significant decrease is detected for 12 and 24h with IL-1β and in combination TNF α. SP-D Significant decrease is detected for 12 and 24h with IL-1β and in combination TNF α. Values are mean and SEM. Statistical significance: *P ≤ 0.05, **P ≤ 0.005, ***P ≤ 0.0005. B: Analysis of immortalized cells C28/I2 (n = 3). Expression of SP-A, SP-B, SP-C and SP-D at 6h, 24h and 72h compared to an untreated control. Values are mean and SEM. Statistical significance: *P ≤ 0.05, **P ≤ 0.005, ***P ≤ 0.0005.