Studies on type II collagen induced arthritis in rats: an experimental model of peripheral and axial ossifying enthesopathy.

It was suggested that type II collagen induced arthritis in rats may be considered an experimental model for rheumatoid arthritis (RA) because of clinical, histological, and immunological similarities. However, some features separate it from RA. We studied 40 inbred female Wistar Furth rats. Two weeks after immunization with native human type II collagen, they had polyarthritis which progressed to ankylosis associated with ossifying enthesopathy and periosteal new bone formation. Inflammatory nodules of the tail appeared after 2 months, with radiological and histopathological aspects of multistage spondylodiscitis. Our findings suggest that collagen induced arthritis may be a relevant model of peripheral and axial ossifying enthesopathy.