Objective To summarize the recent progress of cell-based approaches for promoting bone regeneration in distraction osteogenesis (DO). Methods Recent literature concerning enhancement of bone regeneration following DO using cell-based approaches was reviewed and analyzed. Results An overview of 4 different cell-based approaches was mainly provided: single cell injection, cell scaffold-based strategies/injectable tissue engineered bone, microtissue technology or cell aggregate technology, and stem cell gene therapy. Each has its advantages and disadvantages. Other methods are still in the experimental research except that compound injection of bone marrow mesechymal stem cells and platelet-rich plasma has been applied to clinical practice. Conclusion The cell-based approach is a promising strategy in the field of bone regenerative medicine. These approaches have bright future in promoting bone regeneration and reducing the treatment period in DO in the clinical application. However, well-designed preclinical studies are required to establish safe and effective guidelines for cell-based approaches to promoting bone regeneration during DO.
Objective To investigate whether combining use of platelet-rich plasma (PRP) and decalcified bone matrix (DBM) has synergistic action on promoting bone consol idation and heal ing. Methods Forty male New Zealand rabbits (weighing 2.2-2.8 kg) were randomly divided into 4 groups (n=10). The whole blood was extracted from the central aural artery and PRP was prepared with the Landesberg’s method. An 1 cm-defect was made below the tibiofibular joint of the lefttibia through osteotomy. In group A, defect was repaired by distraction osteogenesis (1 cm); in group B, defect was repaired with 0.5 cm DBM and then by distraction osteogenesis (0.5 cm); in group C, defect was repaired by distraction osteogenesis (1 cm) and local injection of 1 mL PRP; in group D, defect was repaired by 0.5 cm DBM combined with 1 mL PRP and then by distraction osteogenesis (0.5 cm). Then lengthening started at 7 days after operation, at a rate of 1 mm/day and 0.5 mm every time for 10 days (groups A and C) or for 5 days (groups B and D). After the lengthening, the consolidation was performed. The X-ray films were taken at 0, 12, 17, 27, and 37 days after operation. At 37 days after operation, the tibial specimens were harvested for Micro-CT scanning, three-dimensional reconstruction and biomechanical test. Results The X-ray films showed that new bone formation in groups B and C was obviously better than that in groups A and D at 37 days. The bone mineral density (BMD), bone mineral content (BMC), and bone volume fraction (BVF) of groups B and C were significantly higher than those of groups A and D (P lt; 0.05); the BMD and BMC of group C were significantly higher than those of group B (P lt; 0.05); the BVF had no significant difference between groups B and C (P gt; 0.05). There was no significant difference in BMD, BMC, and BVF between groups A and D (P gt; 0.05). The trabecula number (Tb.N) of group C was significantly more than that of other groups (P lt; 0.05), and the trabecula spacing (Tb.Sp) of group C was significantly smaller than that of other groups (P lt; 0.05), but no significant differencewas found among other groups (P gt; 0.05). There was no significant difference in the trabecula thickness among 4 groups (P gt; 0.05). The ultimate angular displacement had no significant difference among 4 groups (P gt; 0.05). The maximum torque of groups B and C was significantly higher than that of groups A and D (P lt; 0.05); the maximum torque of group C was significantly higher than that of group B (P lt; 0.05); no significant difference was found between groups A and D (P gt; 0.05). Conclusion In the rabbit bone defect/lengthening model, local injection of PRP can enhance bone consol idation effectively during consol idation phase. In normal distraction rate, DBM can promote bone consol idation during distraction osteogenesis. In the early stage of distraction osteogenesis, combining use of DBM and PRP can not further promote bone consolidation and healing.
【Abstract】 Objective To evaluate the effectiveness of HA mixed with adenovirus mediated rhBMP-2 gene (AdvrhBMP-2) transferred BMSCs of goats on distraction osteogenesis. Methods Nineteen adult goats were used for the experiment,no matter they were male or female, and the weight of the goats were 15-20 kg. The 10 mL marrow was obtained from theil iac crest of each goat. The BMSCs was expanded and passaged conventionally. The 3th BMSCs was infected by Adv-rhBMP-2 at 200 multipl icity of infection (MOI). The 1×108 infected BMSCs were digested by 0.25% trypsin and collected, then mixed with HA. The right tibia lengthening models were developed, and mixture with BMSCs was injected in the osteotomy position. The goats were divided randomly into 4 groups according to the material injected in operation, group A: Adv-rhBMP-2/BMSCs/HA (n=6); group B: Adv-rhBMP-2/BMSCs (n=5); group C: Adv-β-gal/BMSCs/HA (n=4); group D: sham without any injections (n=4). After a seven-day latency period following ostectomy, distraction was carried out at a rate of 1 mm/day for 4 weeks. Roentgenography was practiced in 5, 8 and 12 weeks. After 12 weeks, the goats were sacrificed and dual-energy X-ray absorptiometry (DXA), biomechanical test and histology results were studied. Results After five and eight weeks surgery, X-raytest showed the distraction callus was more in group A and B than group C and D, and the radiographic score was significantly higher in group A and B than in the other two groups(P lt; 0.05); after 12 weeks surgery, the continued callus was formed in the distraction defects in all groups. DXA showed the mean bone mineral content of distraction callus in group A, B, C, D was (4.175 ± 1.921), (2.600 ± 0.638), (2.425 ± 0.826) and (1.175 ± 0.574) g, and the mean bone mineral density was (0.612 ± 0.196), (0.630 ± 0.159), (0.450 ± 0.166) and (0.266 ± 0.113) g/cm2. The group A and B was significantly higher than group C and D (P lt; 0.05).Biomechanical test showed the maximum loading of group A, B, C, D was (490.20 ± 155.08), (350.59 ± 80.48), (221.95 ± 68.79) and (150.65 ± 92.29) N, and elastic modulus was (178.24 ± 105.80), (105.88 ± 27.09), (81.18 ± 48.67) and (50.35 ± 47.64) MPa. The group A was significantly higher than in group C and D (P lt; 0.05). Histology observation revealed abundant bone formation in the distraction defects in group A, and the bone trabecula was arranged longitudinal and netl ike. Histomorphology analysis revealed the bone volume in group A, B, C, D was 72.35% ± 5.68%, 67.58% ± 7.42%, 49.63% ± 4.87% and 38.87% ± 2.35%, and the bone formation was significantly greater in group A compared with group D (P lt; 0.05). Conclusion HA mixed with rhBMP-2 modified BMSCs can accelerate distraction osteogenesis in goats.
Objective To examine the mRNA expression of activin A(ACT A) and follistatin(FS) during mandibular lengthening and to elucidate the regulating pattern of during mandibular distractionosteogenesis.Methods Skeletally mature-white New Zealand rabbits were established right mandibular distraction osteogenesis models and the mandibles were lengthened 7 days after osteomy. Atthe end of latency period and the end of distraction period, 10,20, 30, 40 and60 days after fixation, the regenerating tissue of animals’ lengthened mandibles and that of the other side normal mandibles were harvested to extract RNA andto analyse ACT A, FS mRNA by RT-PCR.Results The expression of ACT A mRNA was not detectable in normal bone tissue and ACT A mRNA began to express at the end of latency period. The expression of ACT AmRNA increased gradually along with the beginning of distraction and reached the peak on the 10th and 20th days of distraction which was 5.04 and 4.98 times as much as that of the end of latency period, respectively. The trend of expression of FS mRNA during mandibular distraction osteogenesis was the same as expression of ACT A mRNA. Conclusion ACT A/FS play an important role during rabbit mandibular distraction osteogenesis.
Objective To investigate the mode and influential factor of newbone formation following distraction osteogenesis in mandibular lengthening. Methods Corticotomy was performed on bilateral mandibles in twelve adult male goats. A custommade distractor was used to lengthen the mandible at a rate of 1mm/day for 10 days (total 10 mm elongation). Four goats were sampled respectivelyat 2, 4 and 8 weeks after completion of distraction. The lengthening mandibles were examined by roentgenography and histology. Results Newly formed callus was observed in the distraction gap after mandibular lengthening. The new bone exhibited intramembranous ossification generally, but cartilage islands could be found in the specimen that diastractor loosed. Conclusion The above findings indicate that the mode of new bone formation in mandibular lengthening following distraction osteogenesis appears to be intramembranous ossification and that endochondral ossification takes place in case distractor has loosened.
OBJECTIVE: To establish the animal models of mandibular distraction osteogenesis in rabbits and study its osteogenetic mechanism. METHODS: The right mandibles just anterior to the first molars of 12 rabbits were performed osteotomies, and the mandibles were positioned with distractors. The left mandibles were control group without operation. After 1 week, the distractors were stretched 0.9 mm every day for 10 days progressively. One day, 2, 4, 8 weeks after distraction, the mandibles were studied with gross measurement, X-ray, and histological examination. RESULTS: The right mandible were lengthened 8.3 mm on average without bone nonunion and deformity healing. It was observed that the gaps between the distracted bone edges were first occupied by fibrous tissue. Two weeks after distraction, it was found that the gaps were bridged by callus in X-ray, the new bone and the normal bone could not be differentiated clearly after 8 weeks. In histological sections, there were collagen bundles in early distraction, then those collagen bundles were calcificated and become trabeculaes. No Cartilage was found during distraction. CONCLUSION: It suggests that the rabbit mandible can be lengthened by distraction osteogenesis, and the new bone is formed by intramembranous ossification.
ObjectiveTo explore the effectiveness of bone transportation by ring type extenal fixator combined with locked intramedullary nail for tibial non-infectious defect. MethodsBetween June 2008 and October 2012, 22 cases of tibial large segment defect were treated. There were 15 males and 7 females, aged 24-58 years (mean, 36.8 years), including 17 cases of postoperative nonunion or malunion healing, and 5 cases of large defect. After debridement, bone defect size was 5.0-12.5 cm (mean, 8.05 cm). Bone transportation was performed by ring type external fixator combined with locked intramedullary nail, the mean indwelling duration of external fixation was 10.2 months (range, 2-26 months); the external fixation index was 1.57 months/cm (range, 0.3-3.2 months/cm); and the mean length increase was 8.05 cm (range, 5.0-12.5 cm). ResultsAll patients were followed up 19-58 months (mean, 32 months). No infection occurred after operation and all patients obtained bony union, and the union time was 4.7-19.4 months (mean, 11.9 months). Complications included refracture (1 case), skin crease (1 case), lengthening failure (1 case), foot drop (2 cases), retractions of the transport segment (1 case), delay of mineralization (1 case), which were cured after corresponding treatment. According to Hohl knee evaluation system to assess knee joint function after removal of external fixator and intramedullary nail, the results were excellent in 15 cases, good in 5 cases, and fair in 2 cases, with an excellent and good rate of 90.9%; according to Baird-Jackson ankle evaluation system to evaluate ankle joint function, the results were excellent in 10 cases, good in 3 cases, fair in 7 cases, and poor in 2 cases, with an excellent and good rate of 59.1%. ConclusionBone transportation by ring type external fixator combined with locked intramedullary nail could increase stability of extremities, allow early removal of external fixator and avoid axis shift of extremities, so it has good effect in treating tibial noninfectious defect.
ObjectiveTo explore the effectiveness and method of Ilizarov technology for the treatment of infected forearm nonunion. MethodsBetween January 2004 and March 2014, 19 patients with infected forearm nonunion were treated, including 12 males and 7 females with a mean age of 37.4 years (range, 18-62 years). The injury causes included traffic accident in 11 patients, falling from height in 4 patients, and machine twist injury in 4 patients. The patients had received surgical treatment for 1-5 times (mean, 2.7 times). Bone defects located at the radius in 10 cases, at the ulna in 7 cases, and at the radius and ulna in 2 cases. The mean time of chronic infection was 8.3 months (range, 4-16 months). The mean length of the bone defects after debridement was 3.54 cm (range, 2.2-7.5 cm). Under the guidance of C-arm fluoroscope, the Orthofix unilateral external fixator was used to fix. Distraction was performed at 7-10 days after operation, and X-ray film was taken regularly to detect the osteogenesis. ResultsThe mean external fixation time was 6.5 months (range, 3-12 months), and the mean external fixation index was 1.72 months/cm (range, 1.14-2.15 months/cm). All patients were followed up for 35.4 months on average (range, 24-55 months). The bone union time was 3-11 months (mean, 6 months); and no recurrence of infection was observed. At last follow-up, the mean wrist range of motion (ROM) were 52.78° (range, 42-55°) in flexion and 46.53° (range, 40-60°) in extension; the mean elbow ROM were 139.23° (range, 130-150°) in flexion and 3.57° (range, 0-20°) in extension; and the mean forearm ROM were 76.68° (range, 68-90°) in pronation and 81.75° (range, 72-90°) in supination. ConclusionIlizarov technology for infected forearm nonunion can acquire satisfactory clinical results. Radical debridement is the key to control bone infection.
Objective To analyze the application of rigid intra-oral tooth borne distraction device in dento-alveolar distraction osteogenesis. Methods Six patients who underwent orthodontic treatment for maxillary and/or mandibular canine tooth from January to December 2016 in Hanzhong Central Hospital were collected. The bilateral canine tooth was retracted after the first premolar extraction by using the conventional method, and were distracted by the rigid intra-oral tooth borne distraction device, which was made of stainless steel. The tooth movement distance and time, pain and adverse reaction of patients in the process of orthodontics were investigated. Results The number of orthodontic tooth of each patient was 2–4, and the movement range of canine retraction was 6.5–8.0 mm. The time required for canine tooth moving to the second premolar was 13–17 days, and the canine tooth of all the patients were moved, inclined and buccal expanded after three weeks of enhanced fusion. Two patients felt pain and discomfort, one patient experienced buccal mucosa ulcer, and none of the six patients suffered from dysmasesia, dysphagia, periodontitis or tooth enamel loss. Conclusion As an effective tool for orthodontic treatment, the new rigid intra-oral tooth borne distraction device could accelerate the speed of canine movement, and shorten the orthodontic time with few adverse reactions.
Objective To compare the effects of hypoxia-inducible drugs using deferoxamine (DFO) and accordion technique (AT) on activating the hypoxia-inducible factor 1α (HIF-1α)/vascular endothelial growth factor (VEGF) signaling pathway to promote bone regeneration and remodelling during consolidation phase of distraction osteogenesis (DO). Methods Forty-five specific-pathogen-free adult male Sprague-Dawley (SD) rats were randomly divided into the control group, DFO group, and AT group, with 15 rats in each group. All rats underwent osteotomy to establish a right femur DO model. Then, continuous distraction was started for 10 days after 5 days of latency in each group. During the consolidation phase after distraction, no intervention was performed in the control group; DFO was locally perfused into the distraction area in the DFO group starting at the 3rd week of consolidation phase; cyclic stress stimulation was given in the AT group starting at the 3rd week of consolidation phase. The general condition of rats in each group was observed. X-ray films were conducted at the end of the distraction phase and at the 2nd, 4th, and 6th weeks of the consolidation phase to observe the calcification in the distraction area. At the 4th and 6th weeks of the consolidation phase, peripheral blood was taken for ELISA detection (HIF-1α, VEGF, CD31, and Osterix), femoral specimens were harvested for gross observation, histological staining (HE staining), and immunohistochemical staining [HIF-1α, VEGF, osteopontin (OPN), osteocalcin (OCN)]. At the 6th week of the consolidation phase, Micro-CT was used to observe the new bone mineral density (BMD), bone volume/tissue volume (BV/TV), trabecular separation (Tb.Sp), trabecular number (Tb.N), and trabecular thickness (Tb.Th) in the distraction area, and biomechanical test (ultimate load, elastic modulus, energy to failure, and stiffness) to detect bone regeneration in the distraction area. Results The rats in all groups survived until the termination of the experiment. ELISA showed that the contents of HIF-1α, VEGF, CD31, and Osterix in the serum of the AT group were significantly higher than those of the DFO group and control group at the 4th and 6th weeks of the consolidation phase (P<0.05). General observation, X-ray films, Micro-CT, and biomechanical test showed that bone formation in the femoral distraction area was significantly better in the DFO group and AT group than in the control group, and complete recanalization of the medullary cavity was achieved in the AT group, and BMD, BV/TV, Tb.Sp, Tb.N, and Tb.Th, as well as ultimate load, elastic modulus, energy to failure, and stiffness in the distraction area, were better in the AT group than in the DFO group and control group, and the differences were significant (P<0.05). HE staining showed that trabecular bone formation and maturation in the distraction area were better in the AT group than in the DFO group and control group. Immunohistochemical staining showed that at the 4th week of consolidation phase, the expression levels of HIF-1α, VEGF, OCN, and OPN in the distraction area of the AT group were significantly higher than those of the DFO group and control group (P<0.05); however, at 6th week of consolidation phase, the above indicators were lower in the AT group than in the DFO group and control group, but there was no significant difference between groups (P>0.05). Conclusion Both continuous local perfusion of DFO in the distraction area and AT during the consolidation phase can activate the HIF-1α/VEGF signaling pathway. However, AT is more effective than local perfusion of DFO in promoting the process of angiogenesis, osteogenesis, and bone remodelling.