Effects of intranasal corticosteroids in the treatment of experimental acute bacterial maxillary sinusitis in rabbits.

Objective: To investigate the possible effects of intranasal corticosteroids on the focal bacterial colonization and mucosal histomorphological changes in experimental acute bacterial maxillary sinusitis in rabbits.

Methods: Acute bacterial maxillary sinusitis was induced in 48 rabbits. They were divided into 4 groups: antibiotic group (group A), antibiotic and corticosteroid combination group (group B), corticosteroid group (group C), and control group (group D). Six rabbits in each group were sacrificed to obtain secretions from the maxillary sinuses for bacterial culture after they had been treated for 2 or 4 weeks. Maxillary sinuses were removed for whole-mount histological analysis.

Results: The differences between bacterial culture ratios in groups A and B compared with groups C and D were significant after treatment for 4 weeks (p < 0.05), but there was no significant difference between groups A and B (p > 0.05). Semi-quantitative analyses showed that epithelial ulceration and ciliary loss in groups A and B were less pronounced than that in groups C and D (p < 0.05). Infiltration by inflammatory cells diminished more significantly in group B than in groups C and D (p < 0.05). A significant difference in inflammatory cell infiltration between groups A and B was found at the fourth week (p < 0.05). Ultrastructural changes showed a similar trend in both group A and group B.

Conclusions: Intranasal corticosteroids may lessen infiltration by inflammatory cells, and their combined application does not decrease the effects of antibiotic therapy in our study. In the treatment of acute bacterial maxillary sinusitis, intranasal corticosteroids cannot be a substitute for antibiotic treatment as a single therapy, but intranasal corticosteroids administered with antibiotics provide better efficacy.