Study on the Combined Toxicity of Diesel Exhaust Particles and Allergic Pollen

Diesel exhaust particles (DEPs) may increase symptom severity in allergic diseases. To examine possible interaction between DEPs effects and allergic responses, a pollen-sensitized and challenged mouse model of allergic airways disease was utilized. BAL mice were sensitized with 0.15 ml pollen extract or saline injected intraperitoneally on day 0 and day 7. One week after sensitization, mice were exposed to air or different doses of DEPs for 7days. Challenge with pollen was performed at day 21. Blood and lung samples were taken at day 22 after the first sensitization. IgE, IL-4 and oxidative damage indices were measured. IgE and IL-4 was higher in mice immunized with pollen extracts and DEPs than in mice immunized with pollen only. DEPs decreased intracellular superoxide dismutase and glutathione peroxidase, and increased Malondialdehyde in pollen sensitized mice when compared with mice exposed to DEPs alone. In conclusion, this study shows that allergen challenge and exposure to DEPs can interact to enhance allergic responses in sensitized mice, and the oxidative stress may be one of the main mechanisms.