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Experimental gastritis induced by Helicobacter pylori in Japanese monkeys
1Second Department of Internal Medicine, Oita Medical University, Japan.
Abstract:
We used Japanese monkeys (Macaca fuscata) to establish an experimental model in order to clarify the pathogenicity of Helicobacter pylori in gastric and duodenal disorders. A suspension (5 ml; 10(9) CFU/ml) of H. pylori cells isolated from humans was sprayed around the antrum of the stomach of each of 12 of 17 animals with an endoscope. The remaining five animals were not inoculated; they served as a control group. On days 7, 14, and 28 after inoculation, the gastric mucosa samples were examined grossly and were biopsied for microscopic examination with an endoscope. H. pylori was recovered from 7 of the 12 inoculated animals (58%), and infiltration by neutrophils and monocytes was observed histologically. Macroscopic gastritis with erythema and erosions were noted for five of these animals. On day 28 after inoculation, five animals in the infected group were treated with ampicillin. In two infected but untreated animals, the bacteria persisted for more than 6 months. The result of the gastritis scoring of the antral mucosa and the ammonia concentration in the gastric secretion were significantly higher (P < 0.01 to 0.001) for the infected group than for the control group; however, these values decreased to levels comparable to those for the control group after treatment with ampicillin. Urease activity was positive in gastric biopsy specimens from five of the seven animals in the infected group after 7 days and from four of these animals after 14 days but was negative in all specimens from animals in the control group. The level of antibody (immunoglobulin G) in serum for the infected group was elevated but changed very little for the control group. These results suggest that this M. fuscata model can be used to study H. pylori infection and that H. pylori can induce gastritis.
Insights
Japanese monkeys (Macaca fuscata) were infected with Helicobacter pylori to study its effects. The model showed H. pylori can induce gastritis, with symptoms improving after ampicillin treatment.
Area of Science:
- Veterinary Science
- Microbiology
- Gastroenterology
Background:
- Helicobacter pylori is a common human pathogen linked to gastric and duodenal disorders.
- Establishing reliable animal models is crucial for understanding H. pylori pathogenicity.
Purpose of the Study:
- To establish an experimental model using Japanese monkeys (Macaca fuscata) to investigate the pathogenicity of Helicobacter pylori.
- To evaluate the efficacy of ampicillin in treating H. pylori-induced gastritis in this model.
Main Methods:
- Seventeen Japanese monkeys were used; 12 were inoculated with H. pylori, and 5 served as controls.
- Gastric mucosa was examined endoscopically and via biopsy at 7, 14, and 28 days post-inoculation.
- H. pylori recovery, histological analysis, gastritis scoring, ammonia concentration, urease activity, and serum antibody levels were assessed.
Main Results:
- H. pylori was recovered from 58% of inoculated monkeys, with histological evidence of gastritis and macroscopic lesions in some.
- Infected monkeys showed significantly higher gastritis scores and gastric ammonia concentrations compared to controls.
- Ampicillin treatment reduced gastritis and ammonia levels to control group levels; H. pylori persisted in untreated animals for over 6 months.
Conclusions:
- The Macaca fuscata model is suitable for studying H. pylori infection and its effects on the gastric and duodenal systems.
- H. pylori infection in this model leads to gastritis, which can be effectively treated with ampicillin.
- The model allows for the investigation of H. pylori pathogenesis and the evaluation of therapeutic interventions.