NOS2 and chronic kidney disease: The kidneys of C57Bl/6J mice subjected to UUO showed higher mRNA expression of proinflammatory cytokines such as TNF‐α, MCP‐1, and nitric oxide synthase 2 (NOS2) and profibrotic genes such as those encoding fibronectin and collagen I. The transcript levels of these genes were significantly decreased in groups injected with control MSCs or metformin‐treated CKD MSCs (Figure 4a).