Refined Intratracheal Intubation Technique in the Mouse, Complete Protocol Description for Lower Airways Models

Intratracheal intubation (i.t.) in mice is a technique required for many in vivo study protocols, as are the intranasal (i.n.) route or the use of aerosol generators.The i.n. technique is rapid to perform but erratic whereas the transtracheal route requires a short surgery, with anesthesia and a few days needed for total recovery and wound healing before the study can be performed. The i.t. route is a reliable, fast and simple technique and we provide a detailed description for intubation by transthoracic illumination and confirmation in the mouse, using commercially available tools. The result is a technique that takes about 40 seconds to perform, including verification of right positioning of the probe, with no mortality, pulmonary edema, bleeding or laryngeal damage observed. However checking the correct placement of the probe is crucial for good results.This method’s robustness was evaluated by comparing bronchoalveolar lavage (BAL) cell count results, obtained both from i.n. instillation and i.t. inoculation of LPS (E. coli Lipopolysaccharide) to produce a model of lung lower airways inflammation to evaluate anti-inflammatory compounds. We also describe its use as the standard infection technique in an acute Mycobacterium tuberculosis infection model for therapeutic efficacy studies.