Acute exercise induces gastrointestinal leakage of allergen in lysozyme-sensitized mice

Food-dependent exercise-induced anaphylaxis (FDEIAn) is a leading cause of physical allergies. However, the mechanisms involved in the development of FDEIAn are not yet clearly understood. In this study, to investigate the leakage of allergen from the gastrointestinal tract into the circulation, lysozyme (LYZ)-sensitized B10.A mice, which have been shown to exhibit an especially high concentration of plasma antigen-specific immunoglobulin-E (IgE) by sensitization of LYZ as allergen in the white of hens' eggs, and unsensitized mice were made to run on a treadmill after oral LYZ ingestion. Resting mice as well as sensitized and unsensitized animals were used as controls. As a result of the sensitization, total IgE concentration, and levels of LYZ-specific IgE and IgG significantly increased. The running time until exhaustion decreased in the sensitized mice compared with that in the unsensitized mice. Both the sensitization and exercise affected the increase in gastrointestinal leakage of LYZ, which was estimated by immunohistochemical staining of the LYZ antibody in the liver, after oral LYZ ingestion. The exercised sensitized mice were especially closely observed. After oral LYZ ingestion, damage to the villi in the small intestine also occurred following exercise in sensitized mice. Damage to the villi was also noted to have occurred slightly in the resting sensitized mice. These results suggest that allergen leakage from the intestinal tract into the circulation was strongly induced by exercise in the LYZ-sensitized mice and that the mechanisms of FDEIAn might be related to gastrointestinal leakage of allergen due to gastrointestinal mucosal lesions.