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

Figure 2 Supplementation with 1,25-dihydroxy-vitamin D decreases the proinflammatory M1 polarization of hepatic macrophages in non-alcoholic fatty liver disease. Wild-type C57BL/6 mice were fed either normal control (NC) diet or high-fat (HF) diet for 16 weeks, or HF diet plus 1,25-dihydroxy-vitamin D [1,25(OH)2D3] (20 µg/kg) by oral gavage every alternate day for 16 weeks. Phosphate-buffered saline by oral gavage served as a control (n = 10/group). Hepatic macrophages were isolated from mice administered NC diet, HF diet alone or plus 1,25(OH)2D3. A: M1/M2 phenotype of hepatic macrophages determined by immunohistochemical staining (200 ×); B: M1/M2 gene marker expression on hepatic macrophages; C: Proinflammatory cytokine secretion from hepatic macrophages. Values are mean ± SEM, ^aP < 0.05, ^bP < 0.01, n = 10 animals per group; NC: Normal control; HF: High-fat; VD3: 1,25-dihydroxy-vitamin D; iNOS: Inducible NO synthase; TNFα: Tumor necrosis factor α; IL: Interleukin; Arg1 Arginine 1; Mrc2: Macrophage mannose receptor 2.