Airborne particulate matter from goat farm increases acute allergic airway responses in mice

Background: Inhalation exposure to biological particulate matter (BioPM) from livestock farms may provoke exacerbations in subjects suffering from allergy and asthma. The aim of this study was to use a murine model of allergic asthma to determine the effect of BioPM derived from goat farm on airway allergic responses. Methods: Fine (<2.5 μm) BioPM was collected from an indoor goat stable. Female BALB/c mice were ovalbumin (OVA) sensitized and challenged with OVA or saline as control. The OVA and saline groups were divided in sub-groups and exposed intranasally to different concentrations (0, 0.9, 3, or 9 μg) of goat farm BioPM. Bronchoalveolar lavage fluid (BALF), blood and lung tissues were collected. Results: In saline-challenged mice, goat farm BioPM induced 1) a dose-dependent increase in neutrophils in BALF and 2) production of macrophage inflammatory protein-3a. In OVA-challenged mice, BioPM induced 1) inflammatory cells in BALF, 2) OVA-specific Immunoglobulin (Ig)G1, 3) airway mucus secretion-specific gene expression. RNAseq analysis of lungs indicates that neutrophil chemotaxis and oxidation-reduction processes were the representative genomic pathways in saline and OVA-challenged mice, respectively. Conclusions: A single exposure to goat farm BioPM enhanced airway inflammation in both saline and OVA-challenged allergic mice, with neutrophilic response as Th17 disorder and eosinophilic response as Th2 disorder indicative of the severity of allergic responses. Identification of the mode of action by which farm PM interacts with airway allergic pathways will be useful to design potential therapeutic approaches.