TNF and rheumatoid arthritis: In RA bone explants, IL-17A alone or combined with TNF-α induced a significant decrease in BV/TV ratio (0.65-fold with IL-17A and 0.53-fold with IL-17A + TNF-α vs. 1-fold without cytokines, *p < 0.05) whereas in OA bone explants, only the combination of cytokines induced a significant decrease (0.79-fold with IL-17A + TNF-α vs. 1-fold without cytokines, *p < 0.05) (Figure 5A).