The early protective effects of L-arginine and Ng-nitro-L-arginine methyl ester after experimental acute spinal cord injury. A light and electron microscopic study

The purpose of this study was to investigate the early protective effects o f L-arginine and Ng-nitro-L-arginine methyl ester (L-NAME) after acute spin al cord injury. Acute spinal cord injury was performed by epidural applicat ion of an aneurysm clip at thoracic (T) 7 - 11 level, L-arginine at a dose of 750 mu g/kg/min was administered 10 min before acute spinal cord injury and continued for 30 min to 10 animals (Group II). L-NAME at a dose of 250 mu g/kg/min was administered 10 min before acute spinal cord injury and con tinued for 30 min to 10 animals (Group III). No drug was administered to 10 animals after acute spinal cord injury (Group I). Light and electron micro scopic analysis were performed in all of the groups. Oedema of perineural, axoplasm or white matter in the L-arginine-treated group was less than in G roup I and Group III. Thickening in the walls of the arterioles and venules in the L-arginine-treated group was much milder than in Group I and Group III, Degeneration of myelinated axons in the L-arginine-treated group was m ilder than in the control group, But there was no different between Group I I and Group III. (C) 2000 Harcourt Publishers Ltd.