The purpose of this procedure is to record the respiratory function of mice, when submitted to methacholine or hypoxia challenge. Other similar protocols, for allergen sensitization and for LPS challenges, will also be available.
Minimum number of animals: 4 mice of each sex
Age at test: 13 weeks
- Flow chambers
- Computer connected to flow chamber
- Challenge reagents
- Personal safety equipment (masks, gloves, etc.)
- Before starting, make sure the chambers are calibrated
- Weigh the mouse and transfer to test room
- Turn on amplifier, nebulizer and computer
- Place the mouse in the chamber
- Nebulize with PBS for 2 minutes
- Measure response to PBS for 5 minutes
- Nebulize with 12.5mg/ml MCh for 2 minutes
- Measure response to 12.5mg/ml for 5 minutes
- Nebulize with 25mg/ml MCh for 2 minutes
- Measure response to 25mg/ml for 5 minutes
- Nebulize with 50mg/ml MCh for 2 minutes
- Measure response to 50mg/ml MCh for 5 minutes
Additional optional hypoxia challenge:
- Measure response unchallenged for 5 minutes
- Measure response baseline for 5 minutes
- Measure response to challenge with 10% O2 for 5 minutes
- Measure response to challenge with 21% O2 for 5 minutes
- Remove the mouse from its chamber and place back in the home cage.
If any animal is manifesting difficulties at any stage of the procedure, regardless of the test, it should be removed from the nebulizing chamber and allowed to recover. It should not go through the rest of the test nor re-tested.
Aerosolized methacholine leads to bronchoconstriction; Asthmatic patients should not handle this substance nor be present in the room where the challenge takes place due to high risk of asthma attack and health hazard.