Evaluation of Pulmonary Toxicity of Nanoparticles by Bronchoalveolar Lavage

Nanoparticles can enter the body via the lungs, the digestive tract, and the skin. The pulmonary effects of nanoparticles and the underlying mechanisms may be investigated by histopathological examination, immunostaining, bronchoalveolar lavage (BAL), and so on. BAL is a simple, fast, and inexpensive method that is commonly used to investigate the immune cells and acellular components in the lungs, which reflect the health state of the lungs. In this chapter, we describe the detailed procedures of performing BAL on mouse lungs. In a typical procedure, a catheter is inserted in the exposed trachea of a mouse, through which a phosphate-buffered saline (PBS) solution containing ethylenediaminetetraacetic acid (EDTA) is instilled into the lungs by a syringe. BAL fluid (BALF) is collected by gently retracting the instilled solution and massaging the thoracic cavity to maximize BALF retrieval and to minimize shearing forces. The type and number of differentiated immune cells in the BALF are analyzed, and the soluble factors such as total proteins, chemokines, and cytokines in the BALF are determined by protein assay, ELISA, etc.