Effect of L-Arginine Therapy on Vasospasm: Experimental Study in Rats

Abstract

Objective: Cerebral vasospasm occurring after subarachnoid hemorrhage is a serious cause of morbidity. Cerebral vasospasm-related studies aim to prevent complications after subarachnoid hemorrhage. Nitric oxide affects brain blood flow and local vascular hemodynamics. L-arginine is used in the synthesis of nitric oxide, and hence we have investigated the efficacy of L-arginine treatment by using femoral artery vasospasm model.

Methods: Twenty-four male Sprague-Dawley rats have been divided into 3 groups as vasospasm, vasospasm + L-arginine, and control. In this study, we have preferred the "Rat Femoral Artery Vasospasm Model" described by Okada et al. Rats in the vasospasm + L-arginine group were given 300 mg/kg L-arginine for 7 days. At the end of the study, all samples of rat femoral arteries have been dissected and examined microscopically for histopathologic analysis. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests, and P < 0.05 value was considered statistically significant.

Results: L-arginine treatment reduced the morphometric changes such as irregularity of the elastic lamina, disruption of the endothelial cells, vacuolization, and hemorrhages that are caused by vasospasm. When the wall thickness and lumen diameter measurements were evaluated statistically, significant improvement was observed in the vasospasm + L-arginine group compared with the vasospasm group (P < 0.01).

Conclusions: In our study, the use of L-arginine, as a nitric oxide substrate, improved the experimental vasospasm in rats. Therefore we think that L-arginine therapy can be used in the prevention and treatment of cerebral vasospasm after subarachnoid hemorrhage.

Keywords: Cerebral vasospasm; L-arginine; Nitric oxide; Subarachnoid hemorrhage; Vasospasm.