| ObjectiveTeatment of bone defect is a difficult subject in orthopedic surgery. We chose Japanese white rabbit's bone marrow stem cells(BMSCs) that cultured in vitro as seed cells, and bone allograft as a cell carrier composite to repair rabbit radial bone defects.The experiment observes the effect of allograft with bone marrow stem cells to repair radial defect.MethodsAbout 4 ml bone marrow was extracted from below the tibial tubercle of three 2-month-old rabbits, weighing 2.5 kg or so, under sumianxin injection (0.15ml/kg) anesthesia. The bone marrow with heparin anticoagulant was centrifuged. After 14 days, we cultured the bone marrow-derived mesenchymal stem cells to third-generation. The three rabbits'bilateral radius and ulna were incised and 5cm length bone section was obtained under the sterilized conditions. Each piece of bone section would be cut into 3 paragraphs of 1.5cm bone segments, removing soft tissue and bone marrow. After surface decalcified we put the bone segment into -80℃deep frozen for 2 weeks. The bone and bone marrow-derived mesenchymal stem cells were co-cultured for 24 hours after the allograft unfreezed.21 New Zealand white rabbits, weighing 2.5-3kg, with Sumianxin injection (0.15ml/kg) anesthesia were concluded in the experiment. We revealed bilateral radial middle and made 1.5cm long bone-periosteum defect area. In one side, the bone defect was repared with the bone marrow-derived mesenchymal stem cells combined with allogeneic bone as experimental group, and on the other side, the defect was repared by allogeneic bone implants as control group. The third group received no treatment. After 4,8,12 weeks we randomly selected five experimental and control group rabbits and two untreated rabbits to observe the general situation, X-ray film examination and histological examination(HE staining). The results were compared for statistical analysis.Results 1. General observation:After 4,8,12 weeks, the callus in experimental group were more than in the control group. After 4,8 weeks in the experimental group, there were bone callus-like tissues, new bone can be seen in the bone defects. But in the control group there was no significant bone callus-like tissue within the soft tissue, only bone callus formation at both ends. In the untreated group, only relatively dense fibrous scar tissue was seen. After 12 weeks, in the experimental group, new bone generation area was significantly larger than the host bone diameter, but in the control group there was still significant depression, irregular new bone and the new bone were significantly smaller than the host bone; in the untreated group, fibrous tissue surface was still seen.2. X-ray observation:After 4,8,12 weeks callus bone volume in the experimental group ends was more than those in both the control group and the untreated group. After 12 weeks the bone defects of the experimental group achieved bone healing, and bone callus was significantly more than the both ends of host bone, and part of the marrow cavity has been opened. In the control group the bone defects was also healed, but the diameter of the bone tissue was significantly smaller than the host bone.In the untreated group there was only a small amount of callus formation close to the ulnar side.3. Histological examination:After 4,8,12 weeks, woven bone formation in experimental group was significantly more than that in control group. After 12 weeks, the number of trabecular bone was more than that in control group.The X-ray density, histological examination score and the experimental side callus volume were improved in the experimental group, compared with the control side. The former two groups were signficantly more efficient in bone forma-tion than that in the control group in every stage of post implantation (P= 0.001,P<0.01).Conclusions1.BMSCs is the ideal seed cells for bone defects in bone tissue engineering.2.The effect of BMSCs with allogeneic bone repairing bone defects is significantly better than that in allograft. The experiment provides a new reliable method to repair bone defects.
|
PDF Full Text Request