Protective effect of dietary nitrate on experimental gastritis in rats.
Nitrates have long been considered as harmful dietary components and judged responsible for deleterious effects on human health, leading to stringent regulations concerning their levels in food and water. However, recent studies demonstrate that dietary nitrate may have a major role in human health as a non-immune mechanism for host defence, through its metabolism to NO in the stomach. NO is a versatile molecule and although evidence exists showing that administration of low doses of exogenous NO protects against gastrointestinal inflammation, higher NO doses have been shown to exacerbate injury. So, the effect of an ingestion of nitrates in doses corresponding to a normal diet in human consumers on an experimental gastritis induced by iodoacetamide in rats was investigated. During gastritis one of the following compounds was given orally: water; KNO3; the NO donor sodium nitroprusside; the NO scavenger haemoglobin given with either water or KNO3. N(G)-nitro-l-arginine methyl ester (l-NAME), a non-specific NO synthase inhibitor, was administered with either water, iodoacetamide alone, or combined with KNO3. After killing, the stomach was resected and microscopic damage scores, myeloperoxidase and NO synthase activities were determined. Iodoacetamide-induced gastritis was significantly reduced by KNO3 administration, an effect which was reproduced by sodium nitroprusside and reversed by haemoglobin. l-NAME induced gastric mucosal damage in itself, and KNO3 did not prevent the gastritis induced by iodoacetamide associated with l-NAME. In conclusion, dietary nitrate exerts a protective effect against an experimental gastritis in rats by releasing NO in the stomach but such an effect requires the production of endogenous NO.
Larauche
Muriel
M
Neuro-Gastroenterology and Nutrition Unit, Institut National de la Recherche Agronomique, 180 chemin de Tournefeuille, BP3, 31931 cedex 9, France.
Anton
Pauline M
PM
Garcia-Villar
Rafaël
R
Theodorou
Vassilia
V
Frexinos
Jacques
J
Buéno
Lionel
L
Fioramonti
Jean
J
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D004032:Diet; D005753:Gastric Mucosa / Q000378:metabolism*; D005756:Gastritis / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D006454:Hemoglobins / Q000008:administration & dosage; D007460:Iodoacetamide; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009566:Nitrates / Q000008:administration & dosage* / Q000097:blood; D009569:Nitric Oxide / Q000378:metabolism; D020030:Nitric Oxide Donors / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D009573:Nitrites / Q000097:blood; D009599:Nitroprusside / Q000008:administration & dosage; D017680:Potassium Compounds / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D013270:Stomach / Q000473:pathology
D006454:Hemoglobins; D009566:Nitrates; D020030:Nitric Oxide Donors; D009573:Nitrites; D017680:Potassium Compounds; D009599:Nitroprusside; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; C023844:potassium nitrate; D019331:NG-Nitroarginine Methyl Ester; D007460:Iodoacetamide