The establishment of a rhinogenic model of acute sinusitis in rabbits

Objective To create a rhinogenic model of acute sinusitis using an implanted sponge impregnated with pathogenic bacteria in the nasal cavity of the rabbits.Methods Thirty healthy adult male New Zealand white rabbits were used.Five of them were chosen randomly for the measurement of the distances between superior to inferior edge and exterior to interior edge of anterior naris of the right-side nasal cavity and the distance between anterior naris and maxillary ostium.The other 25 were divided into modeling group(10 rabbits),simple blocking group(10 rabbits) and blank control group(5 rabbits).A piece of polyvinyl acetal absorbent sponge(Merocel) in size of(2.5 mm)×5 mm×28 mm was inserted into the right-side nasal cavity of the rabbits in both modeling and simple blocking groups.The sponges were soaked with 1 ml type Ⅲ streptococcus pneumoniae solution and 1ml sterile saline solution in modeling group and simple blocking group respectively.At the 10th day after insertion,the sinuses were examined by computed tomography scans and then all rabbits were sacrificed to obtain the secretions from the right-side maxillary and ethmoidal sinuses for culture,followed by the block remove of the right sinuses for whole-mount histological analyses.Results At the 10th day after insertion,all rabbits survived except one of modeling group died at the 4th day.In modeling group,the positive rate of bacterial culture were 100% in secretions from both the maxillary and ethmoidal sinuses.CT scan showed opacification of right maxillary sinuses and ethmoidal sinuses.Lumenal predominant neutrophilic leukocytes accumulation was observed under light microscope.Epithelial degeneration with ulceration in some areas,and inflammatory cells infiltration of the mucous layer as well as the submucosa were also observed.Eight rabbits in simple blocking group had similar radiological changes,but histopathological changes were lighter in degree than those in modeling group.The results were significantly different between the two groups.Conclusion The rhinogenic model of acute sinusitis has been successfully established in the rabbits,which lays a foundation for the further researches on the pathogenesis and therapia of rhinogenic sinusitis.