Objective To study the past, present and future of bone grafting. Methods Related l iterature on bone grafting in recent years was extensively reviewed. Results Bone grafting had a history over 300 years, a variety of bone grafting candidates including autografting, allografting, xenografting, synthetic and composite bone grafting had been util ized in cl inical orthopedics at present. But bone autografting and allografting represented the preferred alternatives for bone grafting.It would be important trend in bone grafting to fulfill the optimizing design of biomaterials and constructing composite bone substitutes with cells, factors and scaffolds. Conclusion The future bone grafting might be focused on how to achieve the goal of the rapid osseointegration as well as the physiological bone reconstruction.
Objective To explore the clinical application of allogeneic bone transplantation. Methods Related literatures on clinical application of various allograft bone materials of the past 5 years were extensively reviewed. Results The allografts could be processed into various kinds of transplanting materials, such as small blocks, large segments, morselised or granular material, and bone ring, so that they could be applied to bone defect filling, prosthesis revision, limb preservation after tumor resection, and joint fusion. All these applications ended up with good clinical results. However, complications resulted in thestructural transplantation of large block bones could be overlooked. Conclusion The main advantage of bone allograft is that it can be integrated with host bone and be remodelled, so as to reconstruct bone structure and function. How to accelerate their integration and remodelling while exerting normal functions is the problem that requires solution.
Objective To evaluate the effects of composite bone in strategy of tissue engineering on bone defect repair in rats. Methods Sixteen matured Wistar rats (male or female, weighing 250-300 g) were used to prepare platelet lysate (PL). PL/allogeneic decalcified bone granules (ADBG)/Col I (PAC) and ADBG/Col I (AC) were prepared by mixing Col Igel ADBG with or without PL. BMSCs of 8 Wistar rats (male or female, weighing 250-300 g) were isolated and cultured. The 5th passage of BMSCs were co-cultured with PAC at the density of 1 × 106 cells/mL to fabricate the tissue engineered composite PACB in vitro. Forty healthy Wistar rats were made bilateral bone defects in femoral condyles and divided into 4 groups (A, B, C and D, n=10). The defects were filled with equivalent PACB, PAC, AC and Col I in groups A, B, C and D respectively. At 4 weeks, the defect repair was evaluated with radiology, histology, ALP biochemical tests. Results At 4 weeks, the bone density measurement was (7.31 ± 0.54), (4.36 ± 0.67), (2.12 ± 0.47), and (1.09 ± 0.55) pixels in groups A, B, C, and D, respectively. The area of new bone formation in defect area under single view was (412.82 ± 22.31), (266.57 ± 17.22), (94.34 ± 20.22), and (26.12 ± 12.51) pixels in groups A, B, C and D respectively. The ALP contents in femoral condyles were (94.31 ± 7.54), (69.88 ± 4.12), (41.33 ± 3.46), and (21.03 ± 3.11) U/L, respectively. The above indexes of group A were significantly higher than those of groups B, C or D (P lt; 0.05). Three-color flow cytometry assay showed that the T lymphocyte subsets of CD3+CD4+CD8-, CD3+CD8+CD4-, and the ratio of CD4/CD8 displayed no significant difference among four groups (P gt; 0.05). Conclusion Tissue engineered bone PACB is capable to promote the bone defect repair.
Objective To develop a deantigenated porcine bone graft through enzyme treatment and to study the biomechanical properties and osteoinductivity of the xenogeneic bone graft. Methods Deantigenated xenogeneic bone was prepared from porcine bone by a series treatment including α-galactosidase (α-Gal) treatment, freezedrying and irradiation at a does of 25 kGy. Samples were divided into 4 groups according to the treatment methods: fresh bone (group A); deantigenated bone (group B); deantigenated and freezedried bone (group C); deantigenated-freezedried-irradiated bone(group D). SEM observation to group B samples was performed and the diameters of the caves of the porcine cancellous bone were measured. The α-Gal contents of samples of groups A, B, D were measured by ELISA. The effects of different treatments on porcine bone mechanic properties were evaluated through compressive test of 4 groups. The prepared porcine cortical bone were demineral ized and ectopically implanted into muscle groups of hind l imbs of Wistar rats as experimental group, and the demineral ized cortical bone which were inacitviated by high temperature and pressure were implanted as control group. Histological observation was performed and ALP activity was tested at different time postoperatively to investigate the osteoinductivity of the xenogeneic bone implants. Results The porous structure of prepared porcine cancellous bone was similar to that of human cancellous bone. The diameters of the caves were between 150-600 μm. The A value of the groups A, B, D was 0.358 ± 0.027, 0.191 ± 0.011, 0.191 ± 0.009, respectively, with statistically differences between groups (P lt; 0.05). While the biomechanical properties among 4 groups had no statistically difference (P gt; 0.05). Histological observation showed mesenchymal cells immigrated into cartilage and converted into chondrocytes at 3 weeks postoperatively. Cartil iage was formed at 4 weeks and osteoid and more adult cartilage was formed at 6 weeks within the implants of experimental group, while there was no bone formation in control group. ALP activity of experimental group at different times were obviously higher than that of the control group (P lt; 0.05). Conclusion The main xenogeneic antigen of the porcine bone was removed while the mechanic properties and osteoinductivity remained, thus it may be a suitable bone substitute for cl inical use.
Objective To analyze the causes and managing methods of long bone fracture nonunion after allogeneic bone transplantation. Methods From December 1995 to December 2000, 43 cases of postoperative nonunion of long bone fracture were treated. These cases included 31 males and 12 females at the age of 19-57 years (40 years on average). The locations were femur in 11 cases, tibia in 21 cases, humerus in 8 cases and forearm in 3 cases. Bone nonunionafter allogeneic bone transplantation was caused by extensive soft tissue contusion and poor cover around bone fractue site in 6 cases, by incomplete debridement in 8 cases of osteomyel itis (including 6 without continual lavage and 4 only skin flap transfer), by secondary infection of wounds in 3 cases, by severe primary injury or secondary scar covering bone in 12 cases, instable internal fixation in 7 cases, and by earl ier weight bearing in 7 cases. Accroding to Weber classification, there were 4 cases of hypertrophic type and 39 cases of atrophic type. Basing on the type of nonunion, the methods such as refixation, bone retransplantation and transferring tissue flap were chosen to manage the cases. Results Incision healed by first intention in 37 cases, superficial infection occurred and cured after 2 weeks of dressing change in 5 cases, and sinus formed and cured after 2 months of dressing change and drainage in 1 case. All transferring tissue flap survived, and partial necrosis occurred at flap edge in 4 cases and cured after dressing change. All patients were followed up for 38-91 months with an average of 54.6 months. All the nonunion cases achieved bone union 5-11 months with an average of 7.6 months. But low extreme shorten monstrosity occured in 4 cases, malunion in 2 cases, functional l imitation near joints in 7 cases, and rotational l imitation of forearm in 1 case. Conclusion Fracture nonunion after allogeneic bone transplantation mainly shows atrophic type with overall or partial absorption of the allograft bone. The preconditions to guarantee fracture nonunion heal ing include stabil ity of fracture fixation, using transferring tissue flaps, controll ing infection, and adequate bone transplantion.
【Abstract】 Objective To explore the interventional effect of platelet lysate (PL) on osteogenic differentiation ofBMSCs by induction in rats in vitro. Methods Twenty-four clean-grade adult Wistar rats, weighing from 250 g to 300 g, maleor female, were included in this study. PL was obtained through three times of centrifugation and repeated freeze-thaw for the blood aspirated from cardiac cavities in 16 Wistar rats. ELISA assay was conducted to detect the concentration of growth factors PDGF, TGF-β1, IGF-1 and VEGF in PL. The BMSCs harvested by flushing femurs of 8 adult Wistar rats were isolated, cultivated and expanded in vitro. The cells at the 4 passage were performed for osteogenic differentiation by induction in three groups of A (5% PL of final concentration in basic induction medium), B (1% PL of final concentration in basic induction medium), and C (no presence of PL in basic induction medium as a control). The morphological changes of the cells were dynamically observed with inverted phase contrast microscope during the whole period. At different time-points, ALP staining (7 days) and ALP/TP (2, 8, 12 days) of the cells were detected to evaluate ALP activity, and the mineral formation in extracellular martrix was examined with Al izarin red staining which provided quantitative analysis of mineral deposits. Results ELISA assay showed that the content of PDGF, TGF-β1, IGF-1 and VEGF in PL reached (300 ± 30), (140 ± 25), (80 ± 35), (70 ± 20) pg/mL, respectively. Morphological observation displayed BMSCs in group A or B gradually turned from spindle-shape to square- or polygon-shape as the morphorlogical type of osteoblast-l ike cells at 7 days. The cells in group A showed slower shape changesbut higher prol iferation than that in group B or C. Moreover, at the 20 days, the cells in group A still displayed dense gro wth and produced obviously decreased amount of mineral deposits in ECM when compared with group B or C. At the 7 days, the cells ofgroup A showed smaller amount of granules positive for ALP staining in cytoplasm when compared with groups B and C, and displayed marked reduction in ALP activity assay at the 2, 8, and 10 days compared with that of groups B and C (P lt; 0.05). At the 20 days, Al izarin red staining showed the number of mineral deposits in groups A, B and C were 7.67 ± 1.10, 12.87 ± 0.81 and 15.59 ± 0.25, respectively, while the area of mineral deposits were (161 778.70 ± 44 550.80), (337 349.70 ± 56 083.24), and (415 921.70 ± 71 725.39) pixels, respectively. The number of mineral deposits and the area of mineral deposits in group A were smaller than those in groups B and C (P lt;0.05). But there was no statistically significant difference between groups B and C (P gt; 0.05). Conclusion PL is a kind of system carrying various growth factors. Exposure of PL inhibits both ALP activity and mineral formation of BMCs in a dose-dependent way under the osteogenic induction environment.