In Vitro interactions between pulmonary macrophages and respirable particles

Pulmonary alveolar macrophage cells (PAM) are an important component of the pulmonary response to particles deposited in the deep lung. To more fully characterize the interactions between macrophages and particulate materials, a correlative light and electron microscopic technique was developed that allowed light microscopic identification of individual cell viability after in vitro particle exposure, followed by scanning and transmission electron microscopic analyses of specific PAM, including surface morphology, X-ray microanalytic evaluation of particle content, and internal cellular structure. Individual cell viability, particle content, and morphologic alterations were evaluated for three particle types: Ni 3 S 2 , TiO 2 , and glass beads. Cell death and stages of cell disruption including bleb cluster formation, loss of surface features, formation of membrane tears and holes, and cell degranulation correlated with Ni 3 S 2 and TiO 2 content. Glass beads were not associated with cell disruption or viability reduction. Correlative microscopic techniques were essential in describing particle-dependent effects on an individual cell basis.