Histological sections of bovine articular cartilage and histochemical comparison. Metacarpophalangeal joints derived from 3-month-old calves were subjected to a 3-tesla electromagnetic field (EMF) (n = 5) or were left untreated (n = 5). Thereafter, tissue punches including cartilage and subchondral bone were prepared for histological analysis and stained with toluidine blue in accordance with standard protocols. The figure shows two representative sections: (a) control; (b) cartilage after exposure to a 3-tesla EMF. Scale bars, 100 μm.