Effect of lycopene on the vascular endothelial function and expression of inflammatory agents in hyperhomocysteinemic rats.

The aim of this study was to investigate the effect of lycopene on the vascular endothelial function and the expression of inflammatory agents in hyperhomocysteinemic rats. Fifty male Sprague-Dawley rats weighed 145- 155g were on a commercial rat chow diet for seven days, and then were randomized into five groups: normal control group (NC) fed with AOAC diet and four hyperhomocysteinemic groups fed with AOAC diet plus 3% L-methionine. Four hyperhomocysteinemic groups were daily supplemented with 0 (HC), 10 mg/kg (HL1), 15 mg/kg (HL2), 20 mg/kg (HL3) lycopene dissolved in corn oil respectively by intragastric administration for 12 weeks. At the end of experiment, their blood and abdominal aortas were collected after etherization. Serum levels of Hcy were determined by HPLC, nitric oxide (NO) and nitric oxide synthase (NOS) by chromatometry, endothelin- 1 (ET-1), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) by ELISA. Hematoxylin and eosin staining and oil red staining were used to analyze abdominal aortas histologically. Moderate hyperhomocysteinemia was induced in hyperhomocysteinemic groups. Serum level of NO was lower and ET-1 was higher in HC rats than in NC, NL2 and NL3 rats (p<0.01). There was no difference of serum NOS activity among five groups. There were some foam cells and depositions of lipochondria in aortic tunica intima in HC and HL1 rats, which were not found in HL2 and HL3 rats. Serum levels of VCAM-1, MCP-1, IL-8 were higher in HC rats than in NC, NL1, NL2 and NL3 rats (p<0.01). The present study indicated that lycopene exerts an antiatherogenic effect by inhibiting the expression of inflammatory agents in hyperhomocysteninemic rats.