Objectives: Joints arthritis evaluation using conventional ultrasonography is hardly feasible in mice because of the small size of the animal. However, as compared to classical analysis (clinical and histological examination), it is a non invasive method, allowing the follow-up of the same animal during a whole experiment. Moreover, Power Doppler allows the study of the blood flow which reflects inflammatory activity within the synovium of arthtritic joints. We aimed at determining whether ultrasonography analysis could accurately detect arthritis lesions in a mouse model of rheumatoid arthritis (RA), namely collagen-induced arthritis (CIA).
Methods: CIA was induced in 28 mice by immunization with collagen type II. Every week during 8 weeks, ultrasonography and Doppler analysis were performed on knees and ankles of all mice using Ultrasound Bio Microscope (UBM), specially dedicated to the mouse. Clinical and histological evaluations were performed as usual.
Results: We established a semi-quantitative analysis by setting an UBM scoring. UBM grades were correlated to clinical and histological scores of arthritis. Vascularization within the synovium could be estimated by Power Doppler analysis and we settled a semi quantitative grading of vascularization which allowed us to show a good correlation between vascularization scores and histological or clinical scores of arthritis.
Conclusions: This study shows for the first time the possibility to visualize by Ultrasound Biomicroscopic analysis a selected set of joints in a small animal. It provides new perspectives in the evaluation of experimental models of RA and others joint diseases.
- animal model
- power Doppler