Nitric oxide levels in the intestines of mice submitted to ischemia and reperfusion: L-arginine effects.
OBJECTIVE
Usually 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% CO(2) for 5 minutes at 22 degrees C before reoxygenation with 100% O(2) 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 examinations or frozen to -80 degrees 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).


CONCLUSIONS
Supply of L-arginine increased tissue levels of nitricoxide and reduced morphologic intestinal injury among mice undergoing I/R.
Cintra
A E S U
AE
Surgery and Experimentation Pos-Graduation Program, Pediatric Surgery Division, Universidade Federal de São Paulo, UNIFESP, Brazil. cintra@pratica.com.br
Martins
J L
JL
Patrício
F R S
FR
Higa
E M S
EM
Montero
E F S
EF
D000818:Animals; D000831:Animals, Newborn; D001120:Arginine / Q000627:therapeutic use*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000098:blood supply*; D051379:Mice; D008815:Mice, Inbred Strains; D009569:Nitric Oxide / Q000378:metabolism*; D015427:Reperfusion Injury / Q000378:metabolism*; D014184:Transplantation, Homologous
D009569:Nitric Oxide; D001120:Arginine