Bone marrow-derived mesenchymal stem cells versus bone marrow nucleated cells in the treatment of chondral defects

The aim of this study was to compare bone marrow-derived mesenchymal stem cells (MSCs) with bone marrow nucleated cells (BNCs) as seed cells in the treatment of cartilage defects. Twenty Guizhou minipigs were used to create full-thickness chondral defects of 6.0 mm in diameter in the knee joints and divided between two time points (four and eight weeks) for final assessment. At every time point, animals were separated into four groups: the CON group which underwent no implantation; the collagen type II hydrogel group (COL); the collagen type II hydrogel + bone marrow-derived MSCs group; and the collagen type II hydrogel + BNCs group. The samples were grossly examined, observed through a stereo microscope, histologically analysed and evaluated with the O'Driscoll scoring system, respectively. The cartilage repair of the two cell-treated groups was improved markedly compared to the CON and the COL groups, while the repair tissues of the two cell-treated groups showed no significant difference eight weeks after surgery. These data indicate that BNCs contribute to the repair of cartilage with collagen type II hydrogel as scaffolds, which have comparable results with bone marrow-derived MSCs. Moreover, the transplantation of autologous BNCs as seed cells may be a more economical and convenient technique for cartilage repair in clinical applications.