Changes in Upper and Lower Airway Inflammation Following Administration of Mometasone Furoate in Allergen-Challenged Brown Norway Rats

Abstract

In order to assess the antiinflammatory effects of mometasone furoate (CAS 83919-23-7, Sch 32088, MF) in an animal model of allergic airway disease, nasal inflammation (total cell count [TCC] in nasal lavage [NL]) and pulmonary inflammation (total and differential cell count) in bronchoalveolar lavage (BAL), forced vital capacity (FVC) and peak expiratory flow (PEF) were measured in ovalbumin (OVA)-sensitized and -challenged Brown Norway rat following pretreatment with MF or vehicle. Rats were sensitized twice over 14 days with OVA and placed into 1 of 4 protocols: Group 1: intranasal (i. n.) MF (0.001–100 µg/mL) or vehicle once daily for 3 days; Group 2: intratracheal (i. t.) MF (0.001 −0.3 mg/kg i. t.) or vehicle, one dose; Group 3: i. t. MF (0.1–1 mg/kg, i. t.) or vehicle, one dose; Group 4: nose-only inhalation (n. o. i.) of dry powder MF (estimated pulmonary deposition of MF, 1.4, 4.1, and 13.3 µg/kg) or vehicle, once daily for 3 days. Group 1 was challenged with i. n. OVA (1%) 2 h after last treatment dose. Groups 2–4 were challenged with aerosolized OVA (1%) 5 h after treatment. Assessments were performed 24 h post-challenge (Group 1: NL; Group 2: BAL; Group 3 and 4: FVC and PEF). Rats treated with MF demonstrated significant and dose-dependent improvements in nasal inflammation and lung function compared to those treated with vehicle; normalization of these markers to levels consistent with non-sensitized animals were noted at the highest MF doses. Improvements in lung function were similar with i. t. and n. o. i. administration. Pulmonary infiltration of total cells and eosinophils was significantly attenuated after one dose of i. t. MF (0.003–0.3 mg/kg). In this established model of allergic airway disease, MF significantly attenuated cellular infiltration in the upper and lower airways and normalized lung function following allergen provocation.