Determining Expression Levels of the Inflammatory Marker IL-8 in Human Alveolar Basal Epithelial A549 cells following exposure to amorphous Silicon Dioxide Micro- and Nanoparticles in the presence of IL-1B

Abstract

Exposure to nanoparticles and micro particles can have adverse health effects, particularly for the increasing population with pre-existing inflammatory lung conditions such as COPD or asthma. This is of concern in the light of an increased usage of fine particles in the workplace and in consumer products. We studied how pre-existing inflammation and particle exposure are interdependent in cell cultures of A549 cells. A549 cells are immortalized human alveolar basal cells that closely resemble Type II lung epithelial cells. IL-1β was used to induce an inflammatory response and was assessed by measuring interleukin 8 (IL-8). IL-8 is an important pro-inflammatory cytokine expressed in respiratory cells in the human lung, including environmental insults by particles and is associated with neutrophil recruitment. The results indicated that the amorphous silicon dioxide nanoparticles and microparticles alone did not elicit the release of IL-8 or produce inflammation in A549 cells. Also, it was determined that in the presence of inflammation, even brief particle exposure has no enhancement on the inflammatory effect. We speculate that uptake and transcytosis is an efficient clearance mechanism for particles small enough to reach the peripheral lung, where the “mucocilliary elevator” is absent. This clearance mechanism is not associated with inflammation, and thus, prevents unnecessary damage to the lungs.