Gastric expression of inducible nitric oxide synthase and myeloperoxidase in relation to nitrotyrosine in Helicobacter pylori-infected Mongolian gerbils.

• OBJECTIVE: For obscure reasons Helicobacter pylori infection of the gastric mucosa is maintained despite a pronounced host defence response. The present study elucidates possible H. pylori-related interference in the oxy- and nitro-radical formation pathways. MATERIAL AND METHODS: Male Mongolian gerbils were infected with two different H. pylori strains, TN2GF4 and SS1. At 3, 6, 12 or 18 months after inoculation, gastric expressions of myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS) and nitrotyrosine were assessed by Western blotting. RESULTS: Expression of both iNOS and MPO was markedly up-regulated in the H. pylori-infected animals compared with non-infected controls. The TN2GF4-infected animals initially (at 3 and 6 months) demonstrated pronounced expression of both iNOS and MPO. The SSI-infected animals exhibited a slower onset with significantly increased iNOS after 12 and 18 months. Nitrotyrosine expression was slightly elevated in the infected groups at 3 and 6 months compared with that in the controls. Nitrotyrosine levels then decreased and were no longer significantly different from those of controls (TN2GF4-infected animals) or were lower (SS1-infected animals) than in the controls. CONCLUSIONS: The results indicate that peroxynitrite formation as reflected by nitrotyrosine expression is low or even inhibited in chronic H. pylori infection despite pronounced expression of enzymes representing both the oxy- and nitro-radical formation pathways. The results support the theory that H. pylori survival is related to functional inhibition of mucosal enzymatic NO and/or oxy-radical formation.

Keyword

Animals

Blotting

Western

Disease Models

Animal

Gastric Mucosa

metabolism

microbiology

Gerbillinae

Helicobacter Infections

metabolism

microbiology

Helicobacter pylori

pathogenicity

Male

Nitric Oxide Synthase Type II

biosynthesis

Peroxidase

biosynthesis

Pyloric Antrum

metabolism

Pylorus

metabolism

Rats

Severity of Illness Index

Tyrosine

analogs & derivatives

biosynthesis

Publication and Content Type

ref (subject category)

art (subject category)