Bone Marrow Mesenchymal Stem Cells Decrease the Expression of RANKL in Collagen-Induced Arthritis Rats via Reducing the Levels of IL-22

Figure 3

The differences of IL-22 and RANKL among the three groups in FLSs by immunohistochemistry. Representative images of immunohistochemical staining of IL-22 and RANKL in the joint tissue of normal controls (a, d), CIA rats (b, e), and CIA rats treated with MSCs (c, f) (). IL-22- and RANKL-expressing cells were brown in color (magnification: 100x). (a–c) IL-22 expression. (d–f) RANKL expression. When the rats were immunized with type II collagen, the expression of IL-22 and RANKL increased significantly. IL-22: interleukin-22; RANKL: receptor activator of nuclear factor-kappa B ligand; FLSs: fibroblast-like synoviocytes.