Air pollution poses a significant threat to the health of humans, as well as other animals and plants in natural systems. Various species of Alternaria fungi have been found in household and outdoor dust, and contribute to human respiratory diseases, such as asthma. Most in-vivo health studies on both particulate matter (PM) and gas phase pollutants, have used medical intranasal treatment or a small chamber, limiting animal activity. We studied the lung microbiome impacts of Alternaria alternata-associated chemicals using a large, whole-body, multiple animal exposure chamber (constructed with multiple layers of clear acrylic sheets, volume 540L) that simultaneously controls particle size distribution, particulate matter mass concentration, and gas concentration, with uniform dispersion and exposure stability. The chamber system provided realistic whole animal exposures, where dosage was determined by inhalation of particulate matter. A stainless-steel atomizer generated aerosols from an ultrapure water solution of Alternaria filtrate while compressed air was passed through an orifice to break up the solution. The wet aerosol then traversed a heated copper coil at 127 °F transforming water into vapor. The vapor was absorbed when passed through a diffuser dryer filled with silica gel and replaced daily.
Results/Conclusions
The mice exposed to Alternaria filtrate showed a lower total species or Operational Taxonomic Unit (OTU) richness by ~50% compared to the control group in lab air. Further, the variability in community composition between replicate samples exposed mouse lungs was less than half of that of control mouse lungs. The implications of the observed interactions between airborne fungal-derived chemicals and model lung bacterial microbiome are unclear, but the prospect to understand the interactions between the environment and human health are intriguing.