Lipopolysaccharide-Induced Acute Lung Injury in Mice for Exosome and Immune Analysis

Begin with a restrained mouse to induce acute lung injury (ALI).

Take lipopolysaccharides derived from the outer membrane of Gram-negative bacteria, administer intraperitoneally, then return the mouse to its cage.

The lipopolysaccharides reach the lungs, compromise the pulmonary endothelial barrier, and activate alveolar macrophages that release cytokines and exosomes.

The cytokines activate pulmonary endothelial cells and recruit neutrophils. The neutrophils release reactive oxygen species and proteases, damaging the alveolar epithelial and pulmonary endothelial barriers.

Exosomal microRNAs downregulate junctional protein expression in the epithelial and endothelial cells, further weakening the barriers and allowing fluid and immune cells to leak into alveolar spaces, resulting in ALI.

Euthanize the mouse, make a neck incision, and expose the trachea.

Insert a needle to inject a buffer and flush immune cells and exosomes from the alveolar spaces.

Insert a fresh needle to aspirate the alveolar fluid, transfer it to a tube, and store it on ice for downstream analysis.

To begin, load a one-milliliter syringe equipped with a 27-gauge needle with 0.1 milliliters of LPS and PBS per mouse and ma