Background: Previous research suggested that the biofilm of Staphylococcus aureus contributes greatly to the recalcitrant nature of chronic rhinosinusitis (CRS). However, the lack of a simple and stable animal model limited further study in this field. The aim of this study was to create a convenient animal model of S. aureus biofilms in the maxillary sinus of rabbit.
Methods: New Zealand white rabbits were used as model animals and incised vertically along the median line of the nasal dorsum to expose the anterolateral wall of maxillary sinus, on which a 1.5-mm-diameter hole was drilled to enter the sinus cavity. Through the hole, a piece of gelatin sponge was inserted and then inoculated bacterial suspension into the maxillary sinus. One to 8 weeks after the surgery, the sinus mucosa were harvested and examined with scanning electron microscopy (SEM) and hematoxylin and eosin (H&E) staining.
Results: All rabbits tolerated the surgical procedures and had developed sinusitis by the time they were killed. SEM revealed that biofilms were presented in 100% of rabbits who had bacteria infected for ≥2 weeks, during which the ciliated epithelial cells were encapsulated and gradually destroyed. H&E staining revealed morphological changes of the epithelial cells and infiltration of inflammatory cells in the subepithelial layer, which showed a strong correlation with the results of SEM.
Conclusion: This biofilm model of sinusitis avoids excessive damage to the nasal cavity and sinuses of the rabbits. It may be a desirable animal model for studying the pathogenesis and eradication strategies of bacterial biofilms in sinusitis.