[CT evaluation of bone remodeling in rabbit models with rhinosinusitis].

Objective: To evaluate the findings of computed tomography (CT) as objective markers of bone remodeling in rabbit models with chronic rhinosinusitis.

Methods: Forty-eight rabbit models were established by vaccination of staphylococcus aureus. The rabbits were divided into 3 groups according to the time of infection: group A, B and C (4, 8, 12 weeks after infection), 16 rabbits in each group. Each group was subdivided into the medication administration team and the control team, 8 rabbits in each team. All the rabbits were examined by CT before vaccination to rule out the disease of nasal cavity and sinuses, and the CT images were used as the negative control. No interference was given to the control teams which were only examined again by CT when reached the end week. Dexamethasone sodium phosphate were administered to the medication administration teams 2 weeks before the end of experiment, and were examined by CT at the end. The images of both horizontal position and coronal position by reconstruction were obtained. The Hounsfield unit (Hu) of the bone which was the thickest position in each image were measured. The data was analyzed by SPSS 16.0 software. The Hu was analyzed statistically to compare the situation of the bone remodeling in different periods and administration in the rabbit models with CRS.

Results: Average Hu (x±s) of normal rabbits was 810.0±99.7, average Hu at the end time: control team in group A was 964.0±84.6, medication administration team in group A was 833.0±92.5; control team in group B was 987.0±91.5, medication administration team in group B was 886.0±91.6; control team in group C was 1086.0±74.0, medication administration team in group C was 899.8±76.5. The Hu in all groups were higher than normal (t value were 2.747, 4.513 and 7.350 respectively, all P<0.05). No statistical difference was found between control teams of group A and B (t=0.423, P=0.667). The Hu in control team of group C was higher than group B (t=3.905, P=0.001); There was no statistical difference between medication administration teams of group A and B (t=0.892, P=0.384), and group B and C (t=0.886, P=0.385). The Hu of all medication administration teams in 3 groups were lower than all the control teams (t value were 2.717, 3.687, 8.379 respectively, all P<0.05).

Conclusions: Bone remodeling was found in rabbit models with rhinosinusitis, and the phenomenon was more obvious if the period was lengthened. The Hu could reflect the degree of bone remodelling. Glucocorticoids could depress the bone remodeling in the rabbit models with rhinosinusitis.