MDA (micropipette-guided drug administration) Method

Training procedure for MDA method. Picture by Rodent MDA Consortium 2024.

Pharmacological administration method for voluntary per os treatments in mice. This method can potentially be used for different drugs, the preparation of the drug solution depends on the drug`s properties.

Equipment, materials:

• Sweet condensed milk (MIGROS Kondensmilch™, Migros, Zurich, Switzerland)
• Regular Tap Water
• 15 or 50ml Falcon Tubes
• Ultrasonic water bath*
• Magnetic Stirrer*
• Channel p200 Micropipette
• p200 Pipette Tips

* depending on characteristics of drug to be administered

Procedure Preparation Drug Solution**:

• Dilute condensed milk with regular tap water in a 4:10 (condensed milk to water) ratio. This solution is used as vehicle.
• Dilute the drug to be administered per os in water and sonicate for 20 min.
• Mix suspended drug with vehicle solution to reach the desired concentration.
• Keep drug and vehicle solution in constant agitation using a magnetic stirrer.
• Drug and vehicle solution are administered at a volume of 2 ml/kg.

** this section depends on the characteristics of the drug to be administered and might need to be adapted.

MDA Procedure:

• Prepare the desired amount (2 ml/kg) of drug or vehicle solution in the tip of the p200 micropipette. For training you may use vehicle solution only.
• Training Day 1: Restrain mouse gently and expose it to the milk solution for the first time, by offering the pipette tip to the mouth until the mouse begins to drink.
• Training Day 2: Restrain mouse solely by the tail on the metal grid of the food hopper and position the pipette continually next to the mouse’s mouth until it drinks. Animal should ingest the complete volume.
• (Optional) Training Day 3-7: If necessary, repeat the procedure from training day 2 to familiarize the mouse with the milk solution even further. Animal should ingest the complete volume.
• MDA (micropipette-guided drug administration): Place mouse on the metal grid of the food hopper with no or minimal restraint and offer pipette tip until the mouse voluntarily begins to drink the solution.

Videos of the training procedure: https://www.sciencedirect.com/science/article/pii/S0889159120302543?via%3Dihub

Reference: Scarborough J, Mueller F, Arban R, Dorner-Ciossek C, Weber-Stadlbauer U, Rosenbrock H, Meyer U, Richetto J (2020). Preclinical validation of the micropipette-guided drug administration (MDA) method in the maternal immune activation model of neurodevelopmental disorders. Brain Behav Immun. Apr 9:S0889-1591(20)30254-3. doi: 10.1016/j.bbi.2020.04.015.