An Intragastric Gavage Technique for Controlled Helicobacter Infection in Mice
JoVE Encyclopedia of Experiments
Immunology
0 views • 3:04 min • July 8th, 2025
To establish a Helicobacter pylori infection model, begin with an anesthetized, pathogen-free mouse. Restrain the mouse firmly to minimize movement during the procedure.
Take a syringe filled with a bacterial suspension. Connect a polyethylene catheter to the needle of the syringe for intragastric gavage — a technique of delivering the suspension directly into the stomach.
Insert the catheter into the center of the open mouth to access the esophagus, a muscular tube connecting the mouth to the stomach. Gently guide the catheter through the esophagus until it reaches the stomach, and deliver the bacterial suspension directly into its acidic environment.
The inoculated bacteria secrete urease, an enzyme that converts urea into ammonia and carbon dioxide. The ammonia raises the pH of the stomach, neutralizing the acidity and enabling the bacteria to survive.
These bacteria utilize their flagella to traverse through the protective mucus layer, allowing them to reach the gastric epithelium, where they adhere to cells using adhesin proteins. Upon attachment, these bacteria release virulence factors that disrupt the tight junctions between the epithelial cells.
This structural disruption promotes bacterial invasion and colonization in deeper tissues, ultimately establishing a controlled infection in the stomach.
Add bacterial suspensions to 15-milliliter polystyrene tubes, and use a plastic loop to transfer one 10- to 20-microliter droplet from each culture onto individual glass microscope slides. Then, assess the viability and motility of the bacteria under phase contrast microscopy at a 100 times magnification.
Only use the H. pylori inocula if the majority of the bacteria have a bacillary shape. H. felis inocula should primarily contain helical-shaped bacteria, and load the inocula into individual disposable 1-milliliter syringes. Equip each syringe with a 23-gauge needle and use plastic paraffin film to attach a disposable polyethylene catheter to each needle.
Next, manually restrain a 6- to 8-week-old specific pathogen-free and Helicobacter-free mouse by the scruff of the neck and tail and insert one catheter into the center of the open jaw. Guide the catheter in a caudal direction toward the esophagus, extending the neck of the mouse to allow ease of access to the stomach through the esophagus and away from the trachea until most or all of the catheter is no longer visible and a resistance is felt. Then, deliver at least 1 x 105 bacteria to ensure an optimal colonization in disease pathology.
Overview
This article describes the establishment of a Helicobacter pylori infection model in mice. The procedure involves intragastric gavage to deliver bacterial suspensions directly into the stomach, allowing for the study of bacterial colonization and its effects on gastric tissue.
Key Study Components
Area of Science
- Microbiology
- Infectious Diseases
- Gastroenterology
Background
- Helicobacter pylori is a bacterium associated with gastric infections.
- Understanding its infection mechanism is crucial for developing treatments.
- The model allows researchers to study bacterial behavior in a controlled environment.
- Inoculation techniques are essential for successful colonization.
Purpose of Study
- To establish a reliable model for studying H. pylori infections.
- To investigate the mechanisms of bacterial survival and colonization.
- To assess the impact of H. pylori on gastric epithelial cells.
Methods Used
- Use of anesthetized, pathogen-free mice for the infection model.
- Intragastric gavage technique for bacterial delivery.
- Assessment of bacterial viability and motility using microscopy.
- Monitoring of bacterial shape and characteristics for inoculation.
Main Results
- Bacteria successfully colonize the stomach by neutralizing acidity.
- Flagella enable bacteria to navigate through mucus to epithelial cells.
- Virulence factors disrupt tight junctions, facilitating deeper tissue invasion.
- Optimal bacterial doses are necessary for effective colonization.
Conclusions
- The established model is effective for studying H. pylori infections.
- Understanding bacterial behavior can inform treatment strategies.
- Future research can build on this model to explore therapeutic interventions.
Frequently Asked Questions
Executive Industry Relevance
Controlled intragastric gavage for Helicobacter infection in mice enables precise modeling of host-pathogen interactions, supporting early-stage target validation and mechanistic de-risking in gastrointestinal disease research. This approach provides reproducible infection parameters, facilitating predictive confidence in preclinical studies and informing portfolio decisions for anti-infective and immunomodulatory programs.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables interrogation of host-pathogen mechanisms relevant to gastric disease.
- Supports functional validation of bacterial virulence factors and host response pathways.
- Facilitates biological de-risking by providing a controlled infection model.
- Improves predictive confidence for downstream therapeutic hypothesis testing.
Screening & Assay Development
- Establishes standardized infection conditions for reproducible compound screening.
- Allows quantitative assessment of bacterial colonization and host tissue response.
- Supports assay development for evaluating anti-Helicobacter agents or immunomodulators.
- Enables platform reuse for comparative studies across bacterial strains or interventions.
Translational & Preclinical Research
- Provides a disease-relevant system for modeling gastric pathologies linked to Helicobacter infection.
- Aligns preclinical findings with translational biomarker development for gastric disease.
- Supports risk-adjusted advancement of candidates targeting infection or inflammation pathways.
- Facilitates continuity from mechanistic discovery to preclinical validation.
Pipeline & Workflow Integration
This intragastric infection model bridges early discovery and preclinical research, enabling hypothesis-driven studies and quantitative readouts for lead identification and validation.
- Discovery Biology: Supports hypothesis testing on bacterial colonization, host response, and virulence factor function.
- Screening: Provides reproducible infection parameters for evaluating candidate efficacy.
- Analytics: Enables quantitative measurement of bacterial load and tissue pathology for comparative analysis.
- Translational Research: Connects mechanistic findings to disease-relevant biomarkers and preclinical endpoints.
- Enterprise Reuse: Offers a standardized, scalable model adaptable to various Helicobacter strains and intervention strategies.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in infection biology.
- Operational Value: Delivers standardized, reproducible, and scalable infection protocols.
- Strategic Value: Informs go/no-go decisions and enhances capital efficiency by reducing late-stage biological risk.
- Portfolio Impact: Enables risk-adjusted prioritization and advancement of anti-infective and immunomodulatory assets.
Implementation Considerations
- Requires expertise in animal handling and infection modeling.
- Needs access to phase contrast microscopy for bacterial viability assessment.
- Demands cross-team standardization of inoculum preparation and dosing.
- Adaptable to different Helicobacter species and mouse strains as supported by the protocol.
- Dependent on maintaining pathogen-free animal colonies and validated bacterial cultures.
Biopharma FAQs
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Last updated: 29 August 2026