The Study Of Spongy Bone Defects Repaired By Bone Marrow Mesenchymal Stem Cells Combined With Allogeneic Bone

To observe the effectiveness of spongy bone defects repaired by bonemarrow mesenchymal stem cells combined with allogeneic bone. To investigateits feasibility of repairing spongy bone defects.Method40New Zealand white rabbits were selected. Allogeneic bone materialderived from4animals, and the other36were studied. The models of spongybone defects (0.6cm×1.2cm) were established artificially in both condyluslateralis femoris of New Zealand white rabbit. One of bilateral femoral condylewas randomly chosen as experimental group, and contralateral side as controlgroup. The experimental groups were implanted with bone marrowmesenchymal stem cells combined with allogeneic bone, and the control groupswere implanted with only autogenic bone. General observation, x-ray and thehistological examinations were performed at4,8and12weeks after operationrespectively， and biomechanics was evaluated at12weeks in turn. Theoutcome of bone defect repair was assessed by means of obtainingLane-Sandhu’s scores.ResultFrom gross observation, bone particles in experimental groups have presented mutual combination, with them of control groups free,4weeks afterimplantation. Bone particles with close integration in experimental groups havecome into being, but the edge around the transplanted bone was blurry, withthem of control groups more connective and the edge around the transplantedbone clear,8weeks after implantation. Boundary between bone particles andperipheral bone, in experimental groups, was difficult to discriminate, and easyto recognize in control groups,12weeks after implantation. From x-rayperspective, bone defect of both groups presented irregular higher density, withexperimental blurry edge and control clear edge,4weeks after implantation.Density of experimental bone defect was largely consistent with peripheral bone,with control groups little consistent with peripheral bone,8weeks afterimplantation. Density of experimental bone defect was more largely consistentwith peripheral bone, with control groups more consistent with peripheral bone,12weeks after implantation. Histologically, there were more new bone and lesswoven bone in experimental groups, but there was only less new bone in thecontrol groups,4weeks after implantation. There were largely mature wovenbone in experimental groups, but there was only less woven bone in the controlgroups,8weeks after implantation. There were a large amount of trabecularformation, mature lamellar bone tissue and part of sequestrum in experimentalgroups, the bone defects of which were repaired basically, while there wereabundant woven bones and largely sequestrum in the control groups, whichwere not repaired effectively,12weeks after implantation. Furthermore, theexperimental group statistically differed from the control group using theLane-Sandhu’s scores（P<0.05）. The maximum pressure load of femoralcondyle and load/strain ratio of experimental groups were statistically higherthan that in the control groups from the biomechanical perspective at12weeksafter operation(P<0.05). But the maximum strain and displacement ofexperimental groups were statistically lower than that of control groups (P<0.05).ConclusionBone allograft can be partially restored spongy bone defects; bone marrowmesenchymal stem cells combined with allogeneic bone could repair rabbitspongy bone defects to provide experimental data for clinical application.