Figure 4

The effects of 1α,25-hydroxyvitamin D₃ (1,25) on prostaglandin E₂ (PGE₂) production by rheumatoid synovial fibroblasts (RSFs) and human articular chondrocytes (HACs) after 48 h incubation. (a) PGE₂production by RSFs (n = 3) showing normalized data for control; + 1,25 (10^-8 mol/l); + interleukin (IL)-1β (0.05 ng/ml); and + IL-1β and 1,25 (0.05 ng/ml and 10^-8 mol/l, respectively). Before normalization, control values for PGE₂ production by RSFs were in the range 500–2000 pg/ml culture medium/10⁶ cells per 48 h. (b) PGE₂ production by HACs (n = 3) showing normalized data for control; + 1,25; + IL-1β; and + IL-1β and 1,25. Before normalization control values for PGE₂ production by HAC were in the range 100–300 pg/ml culture medium/10⁶ cells per 48 h. (c) Normalized data for PGE₂production by IL-1β-stimulated RSFs after preincubation with 1α,25(OH)₂D₃, as follows: A, control; B, +IL-1β; C, 1,25 + IL-1β; D, 1 h preincubation with 1,25, then + IL-1β and 1,25; E, 16 h preincubation with 1,25, then IL-1β + 1,25; F, 16 h preincubation with 1,25, then IL-1β alone. Values are shown as means ± SEM.