Then, we explored the mechanism by which M2 macrophages ameliorate DN in vitro and found that UC-MSC-induced M2 macrophages attenuated the secretion of the chemokine monocyte chemoattractant protein-1 (MCP-1) in hyperglycemia-induced mesangial cells, which led to reduced macrophage recruitment and infiltration. The gene discussed is CCL2; the disease is Hyperglycemia.