Objective To observe the release pattern of the microcysts and the effect of ectopic osteogenesis of combined micromorselized bone by optimized preparation of microcysts. Methods Optimized poly-DLlactide-co-glycolide (PLGA) microcysts manufacturing method was performed with the orthogonal design, and the accumulated release amount of microcysts was calculated at 2 h, 4 h, 8 h, 12 h, 24 h, 36 h, 48 h, 60 h, 72 h, 84 h, 96 h, 120 h, 144 h, 168 h, 192 h, 216 h, 240 h and 264 h. Twentyfour Wistar rats were divided into 4 groups (n=6) and 1 cm length incision was cut in their bilateral thighs skin, forming 48 gluteus maximus muscle sackmodels. In group A,collagen was implanted to bilateral muscle sacks respectively. In group B, collagen and autologous morselized bone were implanted to bilateral muscle sacks. Ingroup C, collagen and rhBMP-2/PLGA delayed release microcysts were implanted to bilateralmuscle sacks respectively. In group D, collagen and morselized bone/rhBMP-2/PLGA delayed release microcysts were implanted to bilateral muscle sacks. Gross and histologic observations were made at 3, 4 and 5 weeks postoperatively.Results Every optimized variance had an effect on particle diameter of microcyst and its encapsulating rate. The microcyst’s surface was smooth and had a fine spheroplast, which released slowly within 11 days in vitro. In thethird week postoperatively, the graft in group A could not be touched, while the graft in all other 3 groups was still found. After 3 weeks, collagen was absorbed completely in group A, the residual collagen could be seen in groups B, C andD. After 4 weeks, collagen could be seen in group A; micromorselized bone continued to be absorbed and became smaller in group B; microsphere became smaller, osteoblasts increased in group C; micromorselized bone and microsphere continuedto be absorbed, oteoblasts and chondroblasts increased. After 5 weeks, implantsbecame small, microsphere was absorbed, osteoblasts and chondroblasts became more in groups B, C and D. Microcysts presented with white granuloshape and were packaged in tissue pieces. Histologic observation showed that the PLGA microcysts in 3 weeks and 4 weeks could be absorbed gradually as the time in vivo, if combining with morselzed bone they could produce abundant induced osteoblasts and chondroblasts. Conclusion Optimizing the preparation technology of microcysts has delayed their release during a long period in vitro. Autologous micromorselized bone can be ectopicly induced to produce large amount of osteoblasts in gluteus maximus muscle sack, where PLGA microcysts can combine organically and bring about the bone formation with less amount of growth factors.
OBJECTIVE To study the function of the composite of bone matrix gelatin(BMG) and plaster in the repairing process of bone defects. METHODS Sixteen New Zealand rabbits which were defected in corpus radii were made as implant zone of bone. Sixteen sides of radii were implanted with the composite of BMG and plaster as experimental group. Others were implanted with BMG(8 sides) and bone stored in alcohol(8 sides) as control groups. The repairing process in bone defects were observed by X-ray and histological examination. RESULTS There was an obvious osteogenesis in experimental group. The defects of radii were almost healed at 12th week after operation. There were osteogenesis in both control groups, but the repairing process was slower than that of the experimental group. CONCLUSION The composite of BMG and plaster is a good material for bone transplantation.
Objective To evaluate the tissue response induced by three kinds of bone transplantation materials implanted in rat so as to provide proper evidence for their cl inical appl ication. Methods Thirty-six healthy mature Sprague- Dawly mice, weighing from 229 g to 358 g, were randomly assigned to groups A and B (n=18). Three kinds of materials wereimplanted into muscles of rats. Calcium sulfate (CS) granular preparations and allogeneic demineral ized bone matrix (DBM) were transplanted into the left (group A1) and right (group A2) thigh muscle pouches of group A. Respectively, whereas xenogenic DBM were transplanted into the left (group B1) thigh muscle pouches of group B and the right (group B2) sites were taken as control without implant. The samples (n=6) were collected to make the observation of gross and histology and to analyze histological score after 2, 4, and 6 weeks. Results The gross observation: implanted materials were gradually absorbed at late stage in group A1. No obvious degradation and absorption, but fibrosis of tissues were observed in group A2 and B1. The inflammatory reactions were more severe in groups A2 and B1. In group B2, only the changes of scar were seen at operative site. The histological observation: no obvious inflammatory reactions were seen in group A1, CS were gradually absorbed and completely absorbed at 6 weeks, while fibrosis of tissues increased at late stage. Inflammatory reactions in group A2 and group B1 were alleviated gradually, no obvious absorption and degradation were observed. The different two DBM could induce granulation tissues and bone formation at different sites and secondary fibrosis with no obvious immune response was observed. In group B2, there was an increase in collagen fiber density and angiogenesis at late stage. The scores of inflammatory infiltration were significantly higher in groups A2, B1 than in groups A1, B2 (P lt; 0.05), and the scores of fibrosis was larger in groups A1, A2 and B1 than in group B2 (P lt; 0.05). Conclusion CS has rapid dissolution and good biocompatibil ity. It is a good replaceable packing materials of bone defects in some upper l imb’s or acute bone fracture. Both of two DBM have biocompatibil ity and osteoinductive potential, which dissolution are very slow. Due to these capacity, they can be served as an ideal materials in treatment of lower l imb’s bone defect and nonunion.
Objective To investigate the expression levels and significance of vascular endothel ial growth factor (VEGF) and microvessel density (MVD) in rabbit radius defects repaired with allogeneic and autogenic bone. Methods Forty adult New Zealand rabbits were chosen, and 10 mm bone defect model was created in the bilateral radii of 28 experimental rabbits. The other 12 rabbits provided allogeneic bone under the standard of American Association of Tissue Bank. In the left side, allogeneic bone were used to repair bone defect (experimental group), equal capacity autogenous il iac bone was used in the right side (control group). Animals were sacrificed at 2, 4, 8, and 12 weeks postoperatively. Immunohistochemical method was used to determine the expression of VEGF, CD34 protein and MVD counting. Bone histomorphometric parameters, including percent trabecular area (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp) were measured by von Kossa staining undecalcified sl ices. The relation was analyzed between VEGF and MVD, histomorphometric parameters. Results The positive signals of VEGF protein were detected in cytoplasm of vascular endothel ial cells, chondrocytes, osteoblasts, fibroblasts and osteoclasts. At 2 weeks, there was no significant difference in VEGF protein expression between experimental group and control group (P gt; 0.05); at 4 and 8 weeks, the expression of VEGF in control group was significantly higher than that in experimental group (P lt; 0.05); and at 12 weeks, there was no significant difference between two groups (P gt; 0.05). There was a positive correlation (P lt; 0.01) between VEGF expression and MVD value in two groups at 2, 4, 8, and 12 weeks postoperatively. There was no significant difference in bone histomorphometric parameters (BV/TV, Tb.Th, Tb.N, Tb.Sp) between two groups at 12 weeks postoperatively (P gt; 0.05), but there was a positive correlation between VEGF expression and parameters of BV/TV, Tb.Th, and Tb.N (P lt; 0.01); and a negative correlation between VEGF and Tb.Sp (P lt; 0.01). Conclusion VEGF can express diversity at different time and positions, and the different expressions indicated various biology significances in the process of the bone heal ing. It can coordinate growth of cartilage and bone and profit vascular reconstruction of allogeneic bone. VEGF may participate in promoting osteogenesis in the course of allogeneic bone transplantation.
In order to observe stereological correlation between new vessels and surrounding tissue, 6 rabbits were used for the following experiments. The mandible defect model was made by cutting 1 cm x 0.5 cm bone from both right and left side of mandible. Then, the left defect was repaired by the bone segment from the right side, and the right defect was repaired by frozen allogenic bone segment. One month later, the metabolism of the bone segments was observed by nuclein scintiphotography. The revascularization of the bone segments was observed by vascular corrosion cast method. It was shown that new vessels from host soft tissue could penetrate the periosteum of allogenic transplanted bone, along the absorbing path, ingrowth into the bone. The metabolism of the bone was active. It was suggested that the vessel growth from host to the graft is one of the main patterns of revascularization.
Objective To study the immunological tolerance induced by blocking the second signal of T cell with extrinsic cytotoxic T lymphocyteassociated antigen 4 immuno globlin(CTLA4-Ig). Methods Fifty-four BALB/C mice, inbred strains, were employed as recipients of bone allografts, using a model of heterotopic muscle pouch. The 54 mice were divided into 3 groups and18 for each group. The first group, in which the donor was C57BL/6 with intraperitoneal injection ofL6(as a control), was named AL group. The second group,also C57BL/6 with injection CTLA4-Ig, was named AC group. The third group,homologous BALB/C with injection of PBS buffer solution, was named AB group.The serum antibody, lymphocyte proliferation of the second stimulation by splenic cell and bone supernatant of donor, the analysis of lymphocyte subsets, a regraft experiment and histology were determined 2, 4 and 6 weeks after transplantation. The second transplantation was to regraft C57BL/6(BC group) and C3H(BHgroup) mice respectively after first 12 mice being transplantated with C57BL/6 and injected with CTLA4-Ig as to detect donor-specificity of immunological tolerance. Results Compared with AB group, AL group created more intensive immune rejection: CD4 T cell subsets(Plt;0.05), the serum antibody(Plt;0.05) and lymphocyteproliferation of the second stimulation by splenic cell and bone supernatant ofdonor (Plt;0.01 and 0.05) were significantly increased. However, the results of AC group showed that CTLA4-Ig significantly inhibited the immune rejection: CD4T cell subsets(Pgt;0.05), the serum antibody (Pgt;0.05), and lymphocyte proliferation of the second stimulation(Pgt;0.05) were similar to those of AB group. Histological observation of AC group showed that lymphocyte infiltration disappeared,cartilage and new bone formed, and bone marrow cavities emerged. A regraft experiment showed that CD4 T cell subsets (Plt;0.05) and lymphocyte proliferation of the second stimulation by splenic cell and bone supernatant of donor(Plt;0.05), BC group was significantly lower than those of BH group. So theimmunological tolerance induced by CTLA4-Ig was of donor-specificity. Conclusion The immunological tolerance induced by CTLA4-Ig was prolonged for 6 weeks. This study provides a brand-new path for bone transplantation, which can be helpful to other organ transplantation.
Objective To investigate the application of rigid internal fixation in mandibular reconstruction with autogenous bone and to evaluate its efficacy. Methods From January 1994 to May 2004, 98 patients with mandibular defect received mandibular reconstruction with autogenous bone by using rigid internal fixation. Seventy-two cases of benign tumor and 26 cases of malignant tumor were included. Four hundred and ono rigid fixation plates were inserted.The clinical results and X-ray films were analyzed and the healing processes were evaluated. The functional and aesthetic results of the mandibular reconstruction were also evaluated according to Lopez assessment system. Results After a follow-up of 1 to 3 years, 95 patients（96.9%）achieved successful effect. The forms and function of the mandibleswere resumed. Eightyone （82.7%）patients were satisfied with the results ofoperations. Thirteen patients（13.3%） achieved acceptable results. Four patients (4.1%) were dissatisfied with the results of operations. Conclusion The rigid internal fixation is conductive to healing and remodeling ofthe transplant bone in mandibular reconstruction.
【Abstract】 Objective To explore the midterm efficacy of superelastic cage implantation for the treatment of osteonecrosisof femoral head (ONFH). Methods From July 1996 to January 1998, 54 patients (75 hips) of ONFH were treatedwith superelastic cage and followed up. Among 54 patients, 5 patients were lost to follow up and 3 patients were dead of myocardialinfarction, renal failure and gastric cancer, respectively. Forty-six patients completed follow up including 32 males and14 females, aged from 21 to 61 with an average of 39 years old. Twenty-nine hips were classified as Ficat Stage Ⅱ and 36 as StageⅢ . Harris score was 58.20 ± 13.82. All patients were evaluated both cl inically and radiographically. Results Postoperatively,forty-six patients (65 hips) were followed up for 86 to 125 months with an average of 8 years and 8 months. Harris score was 80.78 ± 18.77. Twenty-nine hips were rated excellent, 21 good, 2 fair and 13 poor．A total of 76.9% of overall cl inical results were rated as good or excellent. Eight hips (12.3%) with the cage broken were turned to total hip replacement. Radiographicevaluation: 16 hips (24.6%) rated as grade Ⅰ , 34 (52.3%) grade Ⅱ and 15 (23.1%) grade Ⅲ . Conclusion Superelastic cage implantation is one of alternative treatments for ONFH at early and midterm stages. However, long-term follow-up is needed to know whether it is able to cure ONFH and whether cages will be broken as time passes by.
OBJECTIVE: To observe the difference of the fracture reparation using autogeneic-iliac bone and allogenic bone. METHODS: Comminuted fracture of humerus in two sides were made in rabbits. Autogeneic-iliac bone was implanted in one side, while allogenic bone of equal capacity was implanted in the other side. General observation, X-ray, and HE histologic section were done when the rabbits were put to death in different stages. RESULTS: One week after implantation, the graft had been enclosed by connective tissue without infiltration of the inflammatory cells. At the 2nd week, the graft had been enclosed in osteoplastic granulation tissue, and the cartilage callus had formed. At the 3rd week, there had been broken sequestrum among the callus; the cartilage had actively formed the bone; and the medulla had been making. At the 4th week, the sequestrum had disappeared, and the mature callus had appeared; the osteoblasts had arranged in a line around the edge of the mature callus. At the 5th week, the callus was b, compact and approached mature bones. At the 6th week, there had been the compact lamellar structures and the complete haversian’s systems. There was no significant difference between callus of two sides by using image quantitative analysis in the 3rd, 4th week (P gt; 0.05). CONCLUSION: The allogenic bone has good histocompatibility and bone conduction effect, and can be used for bone transplantation substitute with autogenous-iliac bone.
ObjectiveTo investigate the effectiveness of tibial periosteal flap pedicled with intermuscular branch of posterior tibial vessels combined with autologous bone graft in the treatment of tibial bone defects. MethodsBetween January 2007 and December 2013, 19 cases of traumatic tibia bone and soft tissue defects were treated. There were 14 males and 5 females, aged from 18 to 49 years (mean, 28 years). The tibial fracture site located at the middle tibia in 6 cases and at the distal tibia in 13 cases. According to Gustilo type, 4 cases were rated as type Ⅲ A, 14 cases as type Ⅲ B, and 1 case as type Ⅲ C (injury of anterior tibial artery). The length of bone defect ranged from 4.3 to 8.5 cm (mean, 6.3 cm). The soft tissue defects ranged from 8 cm×5 cm to 17 cm×9 cm. The time from injury to operation was 3 to 8 hours (mean, 4 hours). One-stage operation included debridement, external fixation, and vacuum sealing drainage. After formation of granulation tissue, the fresh wound was repaired with sural neurovascular flap or posterior tibial artery perforator flap. The flap size ranged from 10 cm×6 cm to 19 cm×11 cm. In two-stage operation, tibial periosteal flap pedicled with intermuscular branch of posterior tibial vessels combined with autologous bone graft was used to repair tibial defect. The periosteal flap ranged from 6.5 cm×4.0 cm to 9.0 cm×5.0 cm; bone graft ranged from 4.5 to 9.0 cm in length. External fixation was changed to internal fixation. ResultsAll flaps survived with soft texture, and no ulcer and infection occurred. All incisions healed by the first intention. All patients were followed up 18-40 months (mean, 22.5 months). All graft bone healed, with the healing time from 3 to 9 months (mean, 6.5 months). No complication of implant loosening or fracture was observed. No pain and abnormal activity in the affected leg occurred. All patients resumed weight-bearing and walking function. The length of the limb was recovered and difference value was 0.5-1.5 cm between normal and affected sides. The function of the knee and ankle joint was good without infection, malunion, and equinus. According to the Johner standard at last follow-up, the results were excellent in 15 cases, good in 3 cases, and fair in 1 case, with an excellent and good rate of 94.7%. ConclusionTibial periosteal flap pedicled with intermuscular branch of posterior tibial vessels combined with autologous bone graft is an effective method to treat bone defect of the tibia.