Amniotic membrane-derived stem cells help repair osteochondral defect in a weight-bearing area in rabbits

Our study evaluated the use of amniotic membrane-derived stem cells for repairing osteochondral defects in a weight-bearing area in rabbits. Twenty-four 3-month-old male or female New Zealand white rabbits were selected. The rabbits were randomly divided into 3 groups of eight, according to the treatment received for an experimentally inflicted femoral medial malleolus lesion, group I received a human acellular amniotic membrane seeded with bone marrow-derived mesenchymal stem cells (HAAM-BMSCs) implant; group II received a simple HAAM implant and the control group received no experimental lesion or treatment. The rabbits were sacrificed at 12 and 24 weeks after the procedures (4 rabbits in each time-point) and the cartilage repair status in each animal was evaluated under the microscope. The tissue of the HAAM-BMSCs group grew well covering an area in the visual field that was significantly larger than that of the HAAM group (p<0.05). The percentage of collagen II-positive area in the HAAM-BMSC group was significantly higher than that in HAAM group (p<0.05). The number of chondrocytes determined by toluidine blue staining was higher in the HAAM-BMSC group than that in the HAAM group (p<0.05). The Wakitani scores of the HAAM and HAAM-BMSC groups were significantly higher (worse) than those of the normal control group (p<0.05), but the score in the HAAM-BMSC group was significantly lower than that in the HAAM group (p<0.05). The Wakitani scores in the HAAM-BMSC group were not different between the two time-points taken. Based on our findings, the amniotic membrane-derived stem cells had a good therapeutic effect in repairing the osteochondral defects in the weight-bearing area, and the number of chondrocytes in the injured area was increased significantly, which accelerated the repair of the damaged tissue in rabbits.