Inflammatory and Cytotoxic Potential of the Airborne Particle Material Assessed by Nasal Lavage and Cell Exposure Methods

Abstract

Exposure to bioaerosols in moisture-damaged indoor environments has been shown to be a potential health risk. The aim of the present study was to evaluate the inflammatory and cytotoxic potential of airborne particle material using both the nasal lavage (NAL) method and a cell exposure study. A 24-h sample collection for airborne particles was performed using personal sampling and microenvironmental measurements in homes and an 8-h sample collection in the working places of the studied subjects. At the end of the sampling period, the production of nitric oxide, tumor necrosis factorα, interleukin (IL)-1β, IL-4, and IL-6 was analyzed in the NAL samples of the subjects. The same mediators, excluding IL-4, were measured in the cell culture medium of mouse RAW264.7 macrophages, which were exposed to the pooled filter extracts representing personal, home, and workplace exposure of each individual during the 24 h before the NAL. Samplings were repeated after 2 wk. The subjects were divided into groups of "low exposure" and "high exposure" according to the concentrations of viable fungi, viable bacteria, or total microbial amount in the pooled extract. Cytokine levels in the NAL samples of subjects with high microbial exposure were slightly increased compared to the corresponding values of the subjects with low exposure. Filter samples collected from the subjects with high microbial exposure induced a significant increase in the production of cytokines in the RAW264.7 macrophages, as compared to those from the subjects with low exposure. The within-subject variation was low in all of the cytokine measurements, but the correlation between the studied methods was poor. In conclusion, both of the methods discriminate at the group level between subjects with high and low microbial exposure. Sampling of airborne particle material and exposure of the mammalian cells to the obtained samples seems to be highly applicable in the environmental monitoring, whereas examination of the exposed subjects directly, for example by using the NAL method, is essential when association between exposure and health effects is evaluated.