Cilostazol reduces atherosclerosis by inhibition of superoxide and tumor necrosis factor-α formation in low-density lipoprotein receptor-null mice fed high cholesterol

This study shows that 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl) butoxy]3,4- dihydro-2(1H)-quinolinone(cilostazol) suppresses the atherosclerotic lesion formation in the low-density lipoprotein receptor (Ldlr)-null mice. Ldlr-null mice fed a high cholesterol diet showed multiple plaque lesions in the proximal ascending aorta including aortic sinus, accompanied by increased macrophage accumulation with increased expression of vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1). Supplementation of cilostazol (0.2% w/w) in diet significantly decreased the plaque lesions with reduced macrophage accumulation and suppression of VCAM-1 and MCP-1 in situ. Increased superoxide and tumor necrosis factor-alpha (TNF-alpha) production were significantly lowered by cilostazol in situ as well as in cultured human umbilical vein endothelial cells (HUVECs). TNF-alpha-induced increased inhibitory kappa B alpha degradation in the cytoplasm and nuclear factor-kappa B (NF-kappa B) p65 activation in the nuclei of HUVECs were reversed by cilostazol (1 similar to 100 mu M) as well as by (E)- 3[(4-t-butylphenyl) sulfonyl]-2- propenenitrile (BAY 11-7085) (10 mu M), suggesting that cilostazol strongly inhibits NF-kappa B activation and p65 translocation into the nuclei. Furthermore, in gel shift and DNA-binding assay, cilostazol inhibited NF-kappa B/DNA complex and nuclear DNA-binding activity of the NF-kappa B in the nuclear extracts of the RAW 264.7 cells. Taken together, it is suggested that the antiatherogenic effect of cilostazol in cholesterol-fed Ldlr-null mice is ascribed to its property to suppress superoxide and TNF-alpha formation, and thereby reducing NF-kappa B activation/transcription, VCAM-1/MCP-1 expressions, and monocyte recruitments.