Carrageenan-induced arthritis in the rat.

This study documents a model of carrageenan-induced chronic inflammatory arthritis in the rat, using quantitative histomorphometric assessment. Ten Sprague-Dawley female rats were randomly assigned to one of two groups. Arthritis was induced in the right tibiofemoral joint by 7 intra-articular injections of 0.02 mL of 1% carrageenan in the arthritic group over 24 days. The control (normal) group was injected with 0.02 mL of saline in the right tibiofemoral joint. Sagittal sections of the right knee joint (distal femur and proximal tibia) were assessed by histomorphometry using the LECO 2001 image analysis system. Articular cartilage thickness, epiphyseal plate thickness, subchondral bone plate thickness, trabecular bone volume and thickness of the synovial lining cell layer were measured. Differences between normal and arthritic groups were statistically significant for articular cartilage thickness of the femur, epiphyseal plate thickness of both the femur and tibia, subchondral bone plate thickness of the tibia and the thickness of the synovial lining cell layer. These findings demonstrate that carrageenan-induced arthritic changes are similar to other, established models of arthritis in the rat.