BrdU, caspase-3, PARP, and COX-2-immunoreative cells in 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. Changes in the numbers of immunoreactive cells were significantly (p < 0.01 or p < 0.05) inhibited by treatment with calcium gluconate compared with OA controls. Dark brown staining indicates immunoreactive cells; OA, osteoarthritis. Scale bar = 80 μm.