OBJECTIVETo investigate the mechanism of hyperlipidemia- and imflammation-induced functional impairment of the endothelium.

METHODSThe experiment was conducted using 3 groups of rats fed for 20 weeks with standard chow (control group), high-fat diet and high-fat diet with daily fenofibrate treatment (10 mg/kg, starting since the fifth week), respectively. After 4 and 20 weeks of feeding, respectively, serum lipid level and NO concentration were measured in the rats, and the epithelial vascular cell adhesion molecule-1 (VCAM-1) expression and cell adhesiveness to the aortic endothelium were observed.

RESULTSCompared with the control group, the rats with hyperlipidemia induced by long-term high-fat diet feeding showed lower NO concentration and increased leukocyte accumulation on the endothelial surface, exhibiting also stronger and more extensive endothelial expression of VCAM-1. In contrast, the hyperlipidemic rats with fenofibrate treatment shoed significantly decreased VCAM-1 expression and leukocyte adhesion with recovery of the NO level.

CONCLUSIONNO deficiency and activation of inflammation are involved in vascular impairment in rats with high-fat diet-induced hyperlipidemia, and fenofibrate can effectively prevent atherosclerosis by restoring NO concentration and down-regulating VCAM-1 expression in these rats.