Figure 2.

Interleukin (IL)-7 induced osteoclast formation in synovial fluid mononuclear cells (SFMCs) from joint fluid of rheumatoid arthritis (RA) patients. SFMCs were cultured with M-CSF (20 ng/mL), RANKL (50 ng/mL), or IL-7 (2 ng/mL) for 10 days by replacing the medium at 3-day intervals with fresh cytokines as described in Figure 1 (left panel). To determine the effect of pretreatment with IL-7, SFMCs were cultured with IL-7 (2 ng/mL) for 3 days, then treated with M-CSF (20 ng/mL), RANKL (50 ng/mL), or IL-7 (2 ng/mL) for 7 days, replacing the medium as described above (right panel). TRAP staining and enumeration were performed as described in Figure 1. Representative images (A) and quantification (B) of TRAP⁺ cells at days 10 and 15 are shown. Results are representative of five independent experiments with five different donors. Bars represent the mean and p values were obtained using the unpaired two-tailed Student’s t-test. (C) Peripheral blood mononuclear cells were cultured on top of dentine disks in 96-well culture plates in the above condition for 30 days. Then, surface roughness was analyzed as described in Figure 1. Results illustrate three independent experiments (n = 3). Roughness parameter and the number of pits were analyzed as described in Figure 1. The graph represents the mean ± SEM and p values were obtained using the unpaired two-tailed Student’s t-test.