抄録
Femur bone densities and tibialis anterior muscle properties of type II collagen–induced arthritic mice were determined. In addition, voluntary running activities of arthritic mice were compared with those of controls. Arthritis was induced by intradermal injection of type II collagen in adjuvant. Body and muscle weights were lower in arthritic mice than in controls. Cortical and trabecular bone densities and muscle fiber cross-sectional areas were decreased by arthritis. After classifying the arthritic severity into three levels based on the degree of knuckle swelling; slight, intermediate, and severe, cortical and trabecular bone densities and muscle fiber cross-sectional areas and succinate dehydrogenase activities were lowest when arthritis was most severe. Furthermore, arthritic mice, especially those with intermediate and severe, showed lower voluntary running activities. These findings indicate that lower bone density and muscle atrophy of type II collagen–induced arthritic mice are related to arthritic severity and decreased motor activity.
