The effect of Nω-nitro-L-arginine methyl ester and L-arginine on lung injury induced by abdominal aortic occlusion-reperfusion

Purpose. The aim of this study was to examine the effects of N-omega-nitro-L-arginine methyl ester (L-NAME) and and L-arginine on lung injury after aortic ischemia-reperfusion (IR). Methods. Twenty-four Wistar-Albino rats were randomized into four groups (n = 6) as follows: Control (sham laparotomy), Aortic IR (30min ischemia and 120min reperfusion), L-Arginine (intraperitoneal 100mg kg(-1) live weight)+aortic IR, and L-NAME (intraperitoneal 10mg kg(-1) live weight)+aortic IR. In the lung specimens, the tissue levels of malondialdehyde (MDA), vascular endothelial growth factor (VEGF), and nitric oxide (NO) were measured and a histological examination was done. Results. Aortic IR increased MDA, VEGF, and NO. L-Arginine further significantly increased MDA and NO, and decreased VEGF (P < 0.05 vs aortic IR). L-NAME significantly decreased MDA and NO (P < 0.05 vs L-arginine+aortic IR) and increased VEGF (P < 0.05 vs other groups). A histological examination showed the aortic IR to significantly increase (P < 0.05 vs control) while L-arginine also further increased (P > 0.05 vs aortic IR), whereas L-NAME caused a significant decrease in pulmonary leukocyte infiltration (P < 0.05 vs aortic IR). Conclusions. Our results indicate that L-arginine aggravates the lung injury induced by aortic IR, while L-NAME attenuates it.