normal control,showed normal structure of bone, score 0. (I, II) .
CIA, showed severe erosion of articular cartilage, severe destruction of bone, edema, exudates, and a massive influx of inflammatory cells into the subsynovial connective tissue, score 4.(III): CIA+MSC, showed normal articular cartilage, no edema, no exudates and no proliferation of synovial membrane, score 0. (IV).
