Joint Inflammation and Early Degeneration Induced by High-Force Reaching Are Attenuated by Ibuprofen in an Animal Model of Work-Related Musculoskeletal Disorder
Carpal bone articular cartilages (intracarpal joints) and epiphyseal plates from longitudinal sections of paraffin embedded bone that were stained with safranin O and fast green. (a)–(c) Carpal bone articular cartilages in (a) TR (trained controls), (b) HRHF (rats performing high-repetition high-force task for 12 weeks), and (c) HRHF + IBU (HRHF rats receiving ibuprofen treatment in final 8 weeks). Reduced safranin O staining and a paucity of cells in lower cartilage layers are present in an HRHF rat, compared qualitatively to TR and HRHF + IBU. Chondrocytes that appear to be proliferating are present in the HRHF carpal articular cartilage (arrows). (d)-(e) Distal epiphyseal plate of the radius showing (d) an HRHF rat with a near absence of safranin O staining (arrowheads) and an irregularly shaped epiphyseal plate, as compared to (e) HRHF + IBU rat with an intensely stained and thicker epiphyseal plate. Scale bars = 50 μm. epi: epiphyseal plate.