ABSTRACT
Background: The effect of inhaled fluticasone propionate (FP) and salmeterol (SM) on tracheal responsiveness (TR) to methacholine and lung pathology of sensitized guinea pig was examined. Materials and Methods: Six groups of guinea pigs (n = 7) were sensitized to ovalbumin (OA). Three groups were subjected to inhaled FP and SM, one group during (A), one group after sensitization (for 18 days, B) and other group during sensitization but with 18-days delay before measurements (C). Other three groups were treated with placebo. Results: The TR to methacholine and tracheal muscle contractility were significantly higher than those of control group (P < 0.001 for all cases). The lungs of placebo groups showed variable pathological changes (nonsignificant to P < 0.001) compared to control group. TR, intra-alveolar and interabronchoal hemorrhagie (P < 0.001 in only group A) in treated groups with FP and SM were significantly decreased compared to placebo groups. The improvement in all variables in treatment groups A and C were more pronounced than group B. Conclusion: These results showed a protective effect of FP and SM on tracheal responsiveness and lung pathology during sensitization which was more effective than after sensitization.