ObjectiveTo explore the effect of Aspergillus fumigatus on airway eosinophilia and hyperresponsiveness in rat model of chronic asthma. MethodsWistar rats were sensitized by intraperitoneal injections with ovalbumin (OVA) followed by chronic inhalation of nebulized OVA or physiologic saline. Rats were administered via the airways with placebo or aerosolized Aspergillus fumigatus spores suspension mimicking chronic Aspergillus fumigatus exposure. The Penh after acetylcholine provocation was detected using WBP system. The concentrations of IL-5 and eotaxin in BALF were measured by ELISA. The extents of eosinophil infiltration were evaluated on hematoxylin and eosin-stained(HE) and Wright-Giemsa stained BALF cells smear. ResultsAspergillus fumigatus worsened allergic airway inflammation in OVA-challenged rats,as evidenced by enhanced bronchial responsiveness to inhaled acetylcholine and increased bronchial eosinophilia. Elevated airway eosinophilia corresponded with higher levels of IL-5 and eotaxin in the Aspergillus Fumigatus exposure group. Aspergillus fumigatus,however,did not affect bronchial responses,numbers of eosinophils,IL-5 and eotaxin levels in saline challenged mice. ConclusionThe Results show that chronic Aspergillus fumigatus exposure aggravates eosinophilic airway inflammation in asthma rats by enhancing IL-5 and eotaxin production. Aspergillus fumigatus also increases bronchial hyperresponsiveness in asthma rats.