IL-23 promotes osteoclastogenesis in osteoblast-osteoclast co-culture system

The aim of this study was to determine the effect of IL-23 on the activity and proliferation of osteoclasts (OC) in co-culture with osteoblasts (OB). OB and OC were individually separated from the skull and femoral bone of a SD rat. OB-OC co-culture with IL-23 added was designed as the experimental group, while the OB-OC co-culture without IL-23 was the control group. In the experimental group, five different concentrations of IL-23 were added, and the cells were then cultured for 24, 48 and 72 h. For each concentration at these three time points, cell proliferation, tartrate-resistant acid phosphatase (TRAP) activity and the lacunae in the bone slices were evaluated, compared with control group at the same time points. Compared to the control group, proliferation and TRAP activity of OC were significantly increased at 24, 48 and 72 h with addition of 0.5 to 10 ng/mL IL-23 (P<0.05). In addition, a dose- and time-dependent correlation between the effect of IL-23 and osteoclastogenesis was noticed though the comparison. Moreover, the area of lacunar resorption in each experimental group was significantly larger than in the control group (P<0.05). In conclusion, IL-23 promotes the proliferation, TRAP activity and bone resorption of OC in OB-OC co-culture.