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Updated: May 13, 2026
Organoids as Model for Infectious Diseases: Culture of Human and Murine Stomach Organoids and Microinjection of Helicobacter Pylori
Published on: November 12, 2015
Establishment of a small animal model for human Helicobacter pylori infection using germ-free mouse
1First Department of Internal Medicine, Yamaguchi University, School of Medicine, Japan.
Objective:
To understand why oral inoculation of Helicobacter pylori resulted in continuous colonization of the stomach in germ-free athymic mice, but only temporary colonization in mice that were not germ-free.
Methods:
We inoculated germ-free and "not-germ-free" euthymic mice with H. pylori and studied the resulting colonization of the stomach, comparing it against the germ-free athymic mouse model. In addition, we investigated Lactobacillus in the above-described three mouse groups.
Results:
H. pylori were detected in all germ-free athymic mice and all germ-free euthymic mice continuously. However, in all euthymic mice that were not germ-free, H. pylori was detected only temporarily after inoculation. Lactobacilli were detected only in the not-germ-free mouse group. The number of H. pylori in the germ-free euthymic mice was significantly lower than in the germ-free athymic mice during the period of this study after inoculation.
Conclusions:
We therefore suggest that the growth of H. pylori may be suppressed by the immunological system and eradicated by Lactobacilli previously inhabiting the stomach.
Insights
Germ-free mice allowed continuous Helicobacter pylori colonization. In contrast, mice with existing gut bacteria experienced only temporary colonization, suggesting Lactobacilli and the immune system may suppress H. pylori.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Helicobacter pylori is a significant human pathogen, often establishing lifelong stomach infections.
- The role of the host's immune system and indigenous microbiota in controlling H. pylori colonization remains incompletely understood.
Purpose of the Study:
- To elucidate the factors influencing H. pylori colonization persistence in mice.
- To compare colonization dynamics in germ-free versus conventionally colonized mice.
- To investigate the potential role of Lactobacillus species in H. pylori eradication.
Main Methods:
- Oral inoculation of Helicobacter pylori into germ-free athymic mice, germ-free euthymic mice, and conventionally colonized (not-germ-free) euthymic mice.
- Monitoring of H. pylori colonization in the stomach over time.
- Detection and analysis of Lactobacillus populations in the three experimental groups.
Main Results:
- Continuous H. pylori colonization was observed in germ-free athymic and germ-free euthymic mice.
- H. pylori colonization was transient in conventionally colonized euthymic mice.
- Lactobacilli were exclusively detected in the conventionally colonized mice.
- H. pylori levels were lower in germ-free euthymic mice compared to germ-free athymic mice.
Conclusions:
- The host's immunological system likely plays a role in suppressing H. pylori growth.
- The presence of Lactobacilli in the stomach appears crucial for the eradication of H. pylori.
- These findings highlight the importance of a balanced gut microbiota in preventing persistent H. pylori infections.
