Impact of pesticide cocktail on development and severity of allergic asthma

Introduction Allergies and more particularly allergic asthma is a common condition that can appear early childhood and affects millions of Europeans. Indeed, allergic asthma is a real public health problem and represents about 70% of asthmatic patient. The increase asthma can be partly explained by our exposure to various chemical compounds including pesticides during life. However, few studies report the impact of exposure to a mixture of pesticides (cocktail effect) via food at doses below the toxicity thresholds, mimicking real exposure, in the development and severity of asthma. In this context, we sought to determine whether chronic exposure to pesticides is a risk factor in the occurrence and severity of allergic asthma. Methods To do this, we studied the impact of exposure to a cocktail of 6 pesticides in diet, commonly used in agriculture on the development of allergic asthma in a mouse model [1]. Mice were fed with contaminated diet during the entire life including mating, gestation and breastfeeding. Results Our results show a decrease in the reproduction rate in animals exposed to the cocktail of pesticides but also a greater weight gain during gestation. More interestingly, mice exposed to this cocktail show a greater deterioration in their respiratory function (penH, Rrs, Crs, Ers) associated with pulmonary inflammation characterized by an increase in eosinophilic and neutrophilic infiltrate in broncho-alveolar lavage. Moreover, we observed a more pronounced effect in female compared to male in accordance to well-known gender effect in human for asthma. Finally, Th2 and Th17 responses are increase in lung of exposed mice suggesting an increase in the severity of asthma. Conclusion These first results highlight an impact of pesticides via food, even at tolerable daily intakes (TDI) in force on the occurrence but also the severity of allergic asthma to house dust mites.