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 microns +/- 11.26 microns to 21.45 microns +/- 6.34 microns (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 be salutary in prevention restenosis after coronary angioplasty.