Effects of diesel exhausted particles on lung inflammation in OVA-sensitized and single challenged mice

Background : The deleterious effects of atmospheric pollution on human health are also known by increasing incidence and exacerbations of pre-existing lung diseases such as asthma. However, the effects of diesel exhausted particles (DEP) on acute allergic pulmonary inflammation during asthma sensitization process remain unclear. Objective : To evaluate the effects of 5 weeks of DEP exposure during the sensitization process of acute allergic pulmonary inflammation in an experimental murine model. Methods : Male Swiss mice were divided into 4 groups: non OVA-sensitized and saline instillation animals (10 µL/mouse) (Control, n=6), non OVA-sensitized and DEP instillation mice (3 mg/mL-10 µL/mouse) (DEP, n=8), OVA-sensitized and saline instillation animals (OVA, n=6) and OVA-sensitized and DEP instillation mice (DEP+OVA, n=8). 24 hours after OVA or saline aerosol challenge anesthetized mice were euthanized and was performed measures of inflammatory cells from bronchoalveolar fluid (BALF) and IL-4, IL-5, IL-1β, TNF-α and total immunoglobulin IgE levels from lung tissue by enzyme-linked immunosorbent assay. Results : The coexposure to DEP resulted in an increase of eosinophils, neutrophils and lymphocytes in BALF (p<0.001). Total IgE, IL1-β, TNF-α, IL-4 and IL-5 levels measured into lung tissue were increased in OVA and DEP+OVA groups (p<0.001), but DEP exposure was not able to induce higher cytokines levels by itself. Conclusion : In this experimental model, the effects of 5 weeks of DEP exposure on sensitization process resulted in an increase of leucocytes in BALF and cytokines levels in OVA group, suggesting that DEP exposure has an additional effect on lung inflammation in asthma.