The effect of a high-fat diet on murine macrophage activity

The phagocytic, oxygen free radical generating and cytotoxic activities of macrophages from C57BL/6J mice fed either a normal or an atherogenic high-fat diet have been investigated. Phagocytosis of aggregated low density lipoprotein (LDL) was only slightly inhibited by the high-fat diet although phorbol myristate acetate (PMA)-induced hydrogen peroxide (H2O2) and superoxide anion (O2-) production was significantly reduced. Activation of tumoricidal activity against L929 target cells by lipopolysaccharide (LPS) or lymphocyte-derived macrophage-activating factor (MAF), but not N-acetylmuramyl-L-alanyl-D-isoglutamine (MDP), was also significantly reduced in macrophages from mice fed the high-fat diet. These results indicate that an atherogenic diet is capable of significantly affecting the responsiveness of macrophages to a number of stimulatory agents which act via specific membrane receptors.