Direct Tracheal Instillation of Solutes into Mouse Lung

Summary

Intratracheal instillations deliver solutes directly into the lungs. This procedure targets the delivery of the instillate into the distal regions of the lung, and is therefore often incorporated in studies aimed at studying alveoli. We provide a detailed survival protocol for performing intratracheal instillations in mice.

Abstract

Intratracheal instillations deliver solutes directly into the lungs. This procedure targets the delivery of the instillate into the distal regions of the lung, and is therefore often incorporated in studies aimed at studying alveoli. We provide a detailed survival protocol for performing intratracheal instillations in mice. Using this approach, one can target delivery of test solutes or solids (such as lung therapeutics, surfactants, viruses, and small oligonucleotides) into the distal lung. Tracheal instillations may be the preferred methodology, over inhalation protocols that may primarily target the upper respiratory tract and possibly expose the investigator to potentially hazardous substances. Additionally, in using the tracheal instillation protocol, animals can fully recover from the non-invasive procedure. This allows for making subsequent physiological measurements on test animals, or reinstallation using the same animal. The amount of instillate introduced into the lung must be carefully determined and osmotically balanced to ensure animal recovery. Typically, 30-75 μL instillate volume can be introduced into mouse lung.

Protocol

1. Anesthesia

1. Anesthetizing mice with isoflurane may facilitate animal handling and restraint prior to administering anesthesia intraperitaneally. Using an inhaled anesthetic may or may not be suitable for a particular study: determine first the impact of using isoflurane, or any other anesthetic, on proposed lung study.
2. Anesthetize animals with isoflurane. The video shows the use of an isoflurane vaporizer chamber set at 2% isoflurane mixed with oxygen. If you do not have an isoflurane chamber, you can alternatively using standard open-drop exposure techniques. Enclose rats in a bell jar (or other appropriate non-porous container) with a w....

Discussion

Intratracheal instillations have been used in several various studies to evaluate the toxicity of test compounds (6), induce alveolar lung injury (4; 7), replace surfactants (8), as well as alter gene expression via delivery of small oligonucleotides directly into the lung (5). We are currently exploring the use of instilling 1) fluorescent redox-sensitive material into the lung in order to measure oxidative stress in vivo under normal and pathophysiological conditions, as well as 2) instilling fluorescent indicators w.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Isoflurane	Webster Veterinary	14043-220-05
Xylazine	Lloyd, Inc.		New Animal Drug Application #139-236
Ketamine	Bioniche Pharma	67457-001-10
Nair			Available at drug stores
1mL SubQ Syringe	BD Biosciences	309597	26 5/8 G
4-0 Nylon Suture	Ethicon Inc.	1894G.S30