Nitric Oxide Levels in the Intestines of Mice Submitted to Ischemia and Reperfusion: l -Arginine Effects

Abstract Objective Usualy an experimental necrotizing enterocolitis experimental model, we Investigated nitric oxide levels in intestinal tissues of newborn mice with or without l -arginine therapy during sessions of ischemia and reoxygenation. Methods Twenty-six newborn mice from the Wistar EPM-1 lineage, weighing from 4.5 to 6.2 g, were randomly assigned to three groups: G-I/R, hypoxia and reoxygenation; G-Arg, l -arginine treatment I/R; and G-CTL, controls. G-I/R and G-Arg mice underwent twice a day during their first 3 days of life exposure to gas chambers with 100% CO2 for 5 minutes at 22°C before reoxygenation with 100% O2 for another 5 minutes. After 12 hours, all animals were sedated, laparotomized, and had samples of ileum and colon taken and- either formalin fixed histopathologic examations or frozen to −80°C for estimation of tissue nitric oxide levels. Intestinal injuries were classified according to the criteria of Chiu et al. Results The G-I/R and G-Arg groups showed injuries characteristic of necrotizing enterocolitis (NEC) with an improved structural preservation rate in G-Arg. The concentration of nitric oxide in the Ileum was much higher with G-Arg (16.5 ± 4.9; P = 0.0019) G-I/R (7.3 ± 2.0). This effect was not observed in the colon: G-I/R = 10.7 ± 4.6 versus G-Arg = 15.5 ± 8.7 ( P = .2480). Conclusion Supply of l -arginine increased tissue levels of nitricoxide and reduced morphologic intestinal injury among mice undergoing I/R.