Effects of Intranasal Corticosteroids in the Treatment of Experimental Acute Bacterial Maxillary Sinusitis in Rabbits

Abstract

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.

Evaluation of the ability of an experimental model to induce bacterial rhinosinusitis in rabbits

“…After the sponge removal on the 10th day, all animals had unilateral purulent rhinorrhea in the nasal cavity where they were inserted. This result is consistent with those of other studies 15 , 26 , 32 applying similar methods through the rhinogenic route, a model originally proposed by Marks, 20 using only the insertion of toxoid and/or buffer through the nasal cavity. Marks 20 had 83% success with this method; Liang et al 31 obtained 91.7% success in the induction of acute infection.…”

“…Westrin et al 33 used this bacterium for the induction and observed its replacement after an average of five days. Cheng et al 26 did not isolate this agent in any rabbit 10 days after the start of induction. In the present study, S. pneumoniae was not identified in any of the assessed rabbits.…”

“…Anatomical, physiological, and pathological alterations of the paranasal sinuses have been evaluated, 13 , 16 , 22 , 23 and comparisons of the effectiveness of different treatments for rhinosinusitis have been conducted. 8 , 9 , 11 , 24 , 25 , 26 The study and identification of the presence of bacterial biofilms have also been performed. 27 …”

“…Some authors performed the inoculation of the infectious agent inside the maxillary sinus 7 , 22 , 25 , 26 , 28 , 29 and others, inside the nasal cavity. 15 , 20 , 30 The authors chose not to use the first technique, as it is more invasive and causes iatrogenic alterations in the sinus mucosa.…”

Osteitis and mucosal inflammation in a rabbit model of sinusitis

“…Experimental models allow assessments ranging from aspects related to the pathogenesis of rhinosinusitis to the effectiveness of different forms of treatment for this disease. 17 , 18 , 19 , 20 , 21 , 22 Among several methods described for rhinosinusitis induction, this study utilized the introduction of a sponge containing a toxoid agent into one of the nasal cavities of the animals. In addition to being a technically simple and efficient procedure to produce sinusitis in 100% of animals in several studies, 22 , 23 it causes little injury to the nasal mucosa and no sinus injury.…”