In the collagen-induced arthritis (CIA) mouse model, a widely used standard experimental model of RA, MSCs demonstrated therapeutic effects by inducing CD4+Foxp3+ regulatory T cells (Treg) and shifting the immune response from T helper (Th)1 to Th2, thereby reducing the secretion of proinflammatory cytokines such as interleukin (IL)-6, TNF-α, monocyte chemoattractant protein-1 (MCP-1), while increasing the secretion of the anti-inflammatory cytokine IL-10 [11]. This evidence concerns the gene CCL2 and rheumatoid arthritis.