Vitamin D 1,25-Dihydroxyvitamin D3 reduces lipid accumulation in hepatocytes by inhibiting M1 macrophage polarization

Figure 3 Administration of 1,25-dihydroxy-vitamin D inhibits fatty-acid-induced proinflammatory M1 polarization of macrophages. RAW264.7 macrophages were incubated with palmitic acid (0.5 mmol/L) for 24 hours or Dulbecco's modified Eagle’s medium as a normal control. Lipopolysaccharide (100 ng/mL) or interleukin-4 (5 ng/mL) treatment served as positive controls for macrophage M1 or M2 polarization. For administration of 1,25-dihydroxy-vitamin D (1,25(OH)2D3), RAW264.7 macrophages were incubated with 1,25(OH)2D3 (VD3, 20 ng/mL) for a further 24 hours. A: M1/M2 gene marker expression on RAW264.7 macrophages; B: Proinflammatory cytokine secretion from RAW264.7 macrophages. Values are mean ± SEM, ^aP < 0.05, ^bP < 0.01, n = 3 experiments; NC: Normal control; PA; Palmitic acid; VD3: 1,25-dihydroxy-vitamin D; LPS: Lipopolysaccharide; IL: Interleukin; iNOS: Inducible NO synthase; TNFα: Tumor necrosis factor α; Arg1 Arginine 1; Mrc2: Macrophage mannose receptor 2.