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OBJECTIVE: The present study aims to increase the concentration of genetically modified bone marrow mesenchymal stem cells (BMSCs) in the distraction osteogenesis (DO) interstitial space and induce the conversion of BMSCs to osteoblasts to improve the osteogenic efficiency in DO and shorten the treatment period. METHODS: Bone morphogenetic protein 1 (BMP-1) and green fluorescent protein (GFP) gene-modified cell sheets of BMSCs were constructed by tissue engineering. Thirty-six New Zealand white rabbits were randomly divided into three groups: group A (the blank control group), group B (the GFP group) with the injection of GFP gene-modified BMSC sheets into the DO gap, and group C (the BMP-1 group) with the injection of BMP-1 gene-modified BMSC sheets into the DO gap. Rabbits in all three groups were distracted for 5 days at a distraction rate of 2.0 mm/d, once/day. After distraction, the above-mentioned cell sheet suspension was injected into the distraction gap to observe osteogenesis, which was observed by gross specimen observation, micro-computed tomography (Micro-CT) scanning, and histomorphology. RESULTS: The gross specimen observation showed that all animals had smooth and continuous bone cortex in the distraction region with relatively high hardness. The osteogenesis quality or hardness was ranked from the highest to the lowest, as Group C > Group B > Group A. Micro-CT and histomorphological observation revealed that group C had better maturation and bone volume of the new bone in the DO region at weeks 3 and 6 than groups B and A. CONCLUSION: BMP-1 gene-modified BMSC sheets could effectively promote the formation of new bone during rapid DO in the mandible, compensating for the poor osteogenesis caused by rapid distraction and providing a new approach to shorten the DO treatment period in clinical practice.
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Osteogenic efficiency of pre-vascularization and non-vascularization decalcified bone scaffolds in bone defect repair was investigated. Twenty-one Sprague-Dawley (SD) mice were randomly assigned to three groups, and a bone defect area of ~1.5 cm in length in the thigh bone of the right posterior limbs of each mouse was made. Pre-vascularization decalcified bone scaffolds in vitro (group A) and non-treatment decalcified bone scaffolds (group B) were separately implanted. The defect vacancy was considered as the blank control (group C). Sampling was made 4 weeks after the operation for the histological examination, and then the osteogenic efficiency was observed by gross sample, imaging, hematoxylin and eosin staining and Masson's staining. When implanting pre-vascularization decalcified bone scaffolds in vitro, the scaffolding material showed an obvious absorption, and more new bone formations and abundant vascular proliferation were observed. In non-vascularization decalcified bone scaffolds implanting, absorption insufficiency of the scaffolding material was observed, fewer new-born bone formations were shown, and the new vessels were very small and few in number. The pre-vascularization decalcified bone scaffolds had a better osteogenic efficiency.
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BACKGROUND: Guided bone regeneration technology, as a most widely used method for repairing bone defects, has been extensively used in the field of stomatology. However, there are few reports on the guided bone regeneration technology in long bone defects. OBJECTIVE: To explore the effects of guided bone regeneration combined with kidney-tonifying therapy on the repair of femoral bone defects in rats, and investigate its osteogenic efficacy and underlying mechanism. METHODS: Thirty-six Sprague-Dawley rats were randomly divided into six groups: blank group, guided bone regeneration group, high-, moderate-, and low-dose kidney-tonifying groups, and ossotide tablets group. The femur bone defect model of rats was established, and was treated by guided bone regeneration except for blank group. Bio-Gide collagen membrane combined with autologous bone was implanted by guided bone regeneration. The kidney-tonifying groups were given 0.216, 0.108 and 0.054 g/(kg•d) Qianggu capsule via gavage for 8 weeks. The ossotide tablets group was given 0.58 mg/(kg•d) ossotide tablets via gavage for 8 weeks. At 12 weeks after surgery, the osteogenesis was evaluated by X-ray examination, hematoxylin-eosin staining and Masson staining of bone tissue. The mRNA expression levels of alkaline phosphatase, Runx-2, vascular endothelial growth factor and bone morphogenetic protein-2 in bone tissues were detected by quantitative real-time RT-PCR. RESULTS AND CONCLUSION: Results of X-ray examination and hematoxylin-eosin staining and Masson staining of bone tissue showed that the scores of Lane Sandhu and Huddleston in each group were significantly higher than those in the blank group (P < 0.001). The scores in the high-and moderate-dose kidney-tonifying groups were significantly higher than those in the guided bone regeneration group (P < 0.01). RT-PCR results showed that the mRNA expression levels of alkaline phosphatase, Runx-2, vascular endothelial growth factor and bone morphogenetic protein-2 in bone tissue in the high-and moderate-dose kidney-tonifying groups were significantly higher than those in the blank group (P < 0.01), and were superior to the guided bone regeneration group (P < 0.05). In summary, guided bone regeneration combined with kidney-tonifying can significantly promote the repair of femoral bone defects, reduce bone absorption and improve osteogenic efficacy in rats. The mechanism of promoting bone regeneration and angiogenesis may be by up-regulating the expression of related osteogenic factors and angiogenic factors in the environment where the membrane barrier creates a dominant growth of bone tissue.