Histopathological observations of the tibial and femoral articular cartilage. Of sham controls (A, B), OA controls (C, D), and the diclofenac sodium (E, F) or calcium gluconate 100 mg/kg (G, H), 50 mg/kg (I, J), and 25 mg/kg (K, L)-treated groups. Histopathological changes were markedly inhibited by calcium gluconate. Arrows indicate the thickness of tibia or femur articular cartilage; OA, osteoarthritis; gaps indicate the intra-joint space between the articular surface of the tibia and femur. Scale bar = 80 μm.