Nedocromil sodium inhibits canine adenovirus bronchiolitis in beagle dogs

Nedocromil sodium is a non-steroidal, anti-inflammatory drug used to control asthmatic attacks. Our hypothesis is that nedocromil sodium inhibits viral induced airway inflammation, a common trigger of asthma. We nebulized nedocromil sodium to beagle dogs (n=10, ages, mean ± SEM, 149±13 days) before and after inoculation with canine adenovirus type 2 (CAV2). Controls (n=10) received saline aerosols and were either infected with CAV2 (Sal/CAV2, n=7, ages, 140±11 days) or were not infected (Sal/Sal, n=3, 143±0 days). All dogs were anesthetized with choralose (80 mg/kg,i.v.), intubated and mechanically ventilated. Pulmonary function and bronchoalveolar lavage (BAL) were performed using standard techniques. The percent of infected bronchioles was quantitated, by two trained observers blinded to the study group, as the number of inflamed airways of 40 examined bronchioles times 100 for each dog. In our past studies, acute CAV2 infections were associated with bronchial hyperresponsiveness and bronchiolitis in beagle dogs. Nedocromil-treated dogs, however, had significantly (p<0.05) less mucosal inflammation (mean ± SEM, 39 ± 5 %), epithelial denudation (mean ± SEM, 36 ± 5 %), and BAL neutrophilia (mean ± SEM, 11±3) compared to Sal/CAV2 (mean ± SEM, 51± 6 %, 57±4 %, and 33±8 %, respectively). We conclude that pre-treatment with nedocromil sodium aerosols attenuates CAV2 induced airway inflammation in dogs.