The role of L-arginine and inducible nitric oxide synthase in intestinal permeability and bacterial translocation.
BACKGROUND
Arginine has been shown to have several immunological and trophic properties in stressful diseases. Its metabolites, nitric oxide (NO) and polyamines, are related to arginine's effects. Thus, the aim of this study was to determine the effects of the NO donor L-arginine and the role of inducible NO synthase (iNOS) on intestinal permeability and bacterial translocation in a model of intestinal obstruction (IO) induced by a simple knot in the terminal ileum.


METHODS
Male C57BL6/J wild-type (WT) and iNOS knockout (iNOS-/-) mice were randomized into 6 groups: Sham and Sham-/- (standard chow), IO and IO-/- (standard chow +IO), and Arg and Arg-/- (standard chow supplemented with arginine + IO). After 7 days of treatment with standard or supplemented chows, IO was induced and intestinal permeability and bacterial translocation were evaluated. The small intestine and its contents were harvested for histopathological and morphometric analysis and the determination of polyamine concentration.


RESULTS
Pretreatment with arginine maintained intestinal permeability (P > .05; Arg and Arg-/- groups vs Sham and Sham-/- groups), increased polyamine concentration in intestinal content (P < .05; Arg vs IO group), and decreased bacterial translocation in WT animals (Arg group vs IO and IO-/- groups). Absence of iNOS also presented a protective effect on permeability but not on bacterial translocation.


CONCLUSIONS
Arginine supplementation and synthesis of NO by iNOS are important factors in decreasing bacterial translocation. However, when intestinal permeability was considered, NO had a detrimental role.
Departamento de Alimentos da Faculdade de Farmácia da Universidade Federal de Minas Gerais, Belo Horizonte, Brasil. iarapacifico@yahoo.com.br
Iara Eliza Pacífico
IE
Quirino
Valbert Nascimento
VN
Cardoso
Rosana das Graças Carvalho Dos
Rd
Santos
Warlley Pinheiro
WP
Evangelista
Rosa Maria Esteves
RM
Arantes
Jacqueline Araújo
JA
Fiúza
Maria Beatriz Abreu
MB
Glória
Jacqueline Isaura
JI
Alvarez-Leite
Marina Andrade
MA
Batista
Maria Isabel Toulson Davisson
MI
Correia
D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D018988:Bacterial Translocation / Q000187:drug effects*; D004926:Escherichia coli / Q000502:physiology*; D007082:Ileum / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D007415:Intestinal Obstruction / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D007421:Intestine, Small / Q000378:metabolism* / Q000382:microbiology* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics* / Q000378:metabolism; D010539:Permeability; D011073:Polyamines / Q000378:metabolism
D011073:Polyamines; D009569:Nitric Oxide; D001120:Arginine; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse