Long-Term Oral Administration Of L-Arginine Enhances Endothelium-Dependent Vasorelaxation And Inhibits Neointimal Thickening After Endothelial Denudation In Rats

Objective. To further prove the hypothesis that local decrease of nitric oxide (NO) synthesis and/or its activity might be critically important in the disturbance of vascular homeostasis after vascular injuries.Methods. Intimal thickening model induced by air-drying denudation of rat right common carotid artery was performed to evaluate the effects of long-term oral administration of L-arginine on neointimal thickening and acetylcholine-induced endothelium-dependent vasorelaxation (EDR) by histomorphometric and functional studies.Results, Reductions in EDR function persisted and simultaneously developed prominent neointimal thickening by 14 days after denudation. Long-term oral supplementation of L-arginine (1 g/kg/day) significantly enhanced EDR from 43.5%+/- 12..35% to 68.8%+/- 9.0% (n=10, P<0.001) and reduced neointimal thickening from 62.45 mu m +/- 11.26 mu m to 21.45 mu m +/- 6.34 mu m (n = 10, p<0.001) as compared with each control animals.Conclusions, This study shows that oral administration of L-arginine significantly inhibits neointimal thickening and preserves NO-mediated EDR in experimental endothelial denudation, suggesting an important role for L-arginine, NO pathway in the regulation of vascular homeostasis after endothelial injury which might bt: salutary in prevention restenosis after coronary angioplasty.