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

Figure 5

The expression of RANKL mRNA by RT-PCR in FLSs. The different concentrations (0 ng/ml, 0.1 ng/ml, 1 ng/ml, and 5 ng/ml) of IL-22 induced significantly the expression of RANKL mRNA in a dose-dependent manner. Compared between any two different dosing subgroups, the expression increases were significantly different (), except for 0 ng/ml and 0.1 ng/ml IL-22 in the normal group. Notably, after 5 ng/ml of IL-22 treatment, the levels of RANKL mRNA in CIA controls were higher than those in CIA rats transplanted with MSCs, indicating that MSCs downregulated the induction of IL-22 (normal controls: , ; CIA controls: , ; and CIA-MSC group: , ). RANKL: receptor activator of nuclear factor-kappa B ligand. Significant between-group difference (). Significant between-group difference (). Significant between-group difference ().