Objective Choose polylactide-co-glycolide/hydroxyapatite (PLGA/HA) and porous phosphate calcium (PPC) as the object that we will study, compare their degradabality and choose one as a suitable scaffold for rib reconstruction. Methods All the experiments were divided into PLGA/HA group and CPC group. Degradabality experiment in exvivo: put the two scaffold which have the same size into 0.9% NaCl, keep sterile, then put the container into warm cage，get out and weigh them in 2, 4, 8, 12 and 24 weeks, compare the different speed of the two scaffold. Degradability experiment in vivo: put the two scaffold which have the same size under the skin of the rabbit, and weigh them in 2, 4, 8, 12 and 24 weeks, the tissue around the scaffold was examinzed by HE and the scaffold was examined by electron scanning microscope. Results Micro-CT and Scanning electron microscopy shows that CPC group had better structure （1101.2228±0.6184 mg/ccm vs. 1072.5523±0.7442 mg/ccm）and porosity（70.26％±0.45％ vs.72.82％±0.51％）than PLGA/HA group; The result of degradabality experiment in vitro shows that the speed of the two scaffolds was slow. It is at 24 weeks that the degradability is obvious,and the PLGA/HA group degraded a lot which was 60%. The result of degradabality experiment in vivo shows that the speed of degradabality of PLGA/HA group was faster than that is in the 0.9% Nacl, also was faster than that of CPC group which was 96%.The reponse of tissue around the PLGA/HA was more sever than that of CPC group which is in favour of the growth of cells. Conclusion As for the reconstruction of large defect of rib, CPC is more suitable than PLGA/HA.
Objective To summarize the effect of self-setting CPC on the repair of bone defect after tumor resection in children. Methods From December 1998 to December 2006, 32 patients with benign bone tumor were treated, and the bonedefect was repaired by CPC. Among them, there were 21 males and 11 females, aged 4-14 years old (9.8 on average). The course of disease was 3-18 months. There were 12 cases of non-ossifying fibroma, 8 of bone cyst, 7 of osteoid osteoma and 5 of fibrous dysplasia. The bone defect was located in femur in 15 cases, in tibia in 8 cases, in humerus in 6 cases and in other positions in 3 cases. The range of bone defect was 2.0 cm × 1.5 cm × 1.0 cm - 10.0 cm × 5.0 cm × 4.0 cm. CPC spongiosa granules of 3-23 g were filled in 26 cases, including 3 children with pathologic fracture and internal fixation with plate, and injectable CPC of 5-20 mL was filled in 6 bone cyst cases. Results Thirty-two patients obtained heal ing by first intertion. All the patients were followed up for 12-48 months (23.5 months on average). No allergic reaction, toxicity, rash or high fever was found after operation. There was no pain or pruritus at the incisions. The X-ray films showed that the implanted CPC began to fuse with the host bone 4-9 months (7 month on average) after operation. The internal fixation was removed within 6-12 months of operation. And CPC spongiosa granules were absolutely absorbed within 8-36 months of operation. However, injectable CPC could be found 4 years after operation. The children’s l imbs could do normal exercises. Finally, bone matrix grew well and no recurrence was found. Conclusion CPC in repairing bone defect after benign bone tumor in children is a safe, economical, convenient and non-toxic method.
Objective To study in vitro sustained release behaviour of the recombinant human bone morphogenetic protein 2(rhBMP-2) from the sample which porous calcium phosphate cement (PCPC) was combined with rhBMP-2, and to evaluate the effect of PCPC/rhBMP-2 composite on repairing bone defect in the animalstudy.Methods rhBMP-2 was absorbed into PCPC by vacuum-adsorption and freeze-dried at -40℃, the PCPC/rhBMP-2 enwrapped with chitosan as the experimental group, the pure PCPC/rhBMP-2 as the control group, then the sustained release ofrhBMP-2 from PCPC was determined in simulated body fluid (SBF) by UV-VIS spectrophotometer. At same time, the PCPC/rhBMP-2 composites with chitosan were implanted into the (4.2 mm×5.0 mm femora defects of rabbits, which were considered as the experimental group, whereas in the control group only PCPC was implanted. The effect of repairingbone defect was evaluated in the 4th and 8th week postoperatively by radiograph and histomorphology.Results The PCPC have a high absorption efficiency to rhBMP-2, and the release of rhBMP-2 was sustained release system. The release of rhBMP-2 from PCPC in the experimental group (99% after 350 hours) was slowerthan that in the control group (100% after 150 hours). In the experimental group, the radiological and histomorphological evaluations showed that theinterfaces between the materials and host bones became blurred both at 4th and 8th week. The implanted materials were partially absorbed, and the implanted areas exhibited the formation of new bone. In the control group, a little amount of new bones was observed. Conclusion The PCPC shows great clinical potential as a carrier for rhBMP-2. The PCPC/rhBMP-2 composite possesses much potentialities of osteoinductivity and the ability of repairing bone defect, so it can be used as a novel bone substitute clinically.
Objective To investigate the cl inical efficacy of the cancellous granule-type calcium phosphate cement in repair bone defect. Methods Between July 2008 and July 2009, 35 patients (42 l imbs) with fractures, nonunion, and benign bone tumor were treated with cancellous granule-type calcium phosphate cement. There were 32 males and 3 females,with an age range from 9 to 73 years (median, 41 years), including 24 l imb fractures (19 cases), 4 osteotomy for deformity of ulna and radius (2 cases), 2 femur intertrochanteric bony cysts (2 cases), 3 enchondroma (3 cases), 5 bone defect at donor il ium (5 cases), 3 nonunion (3 cases), and 1 lumbar spinal stenosis (1 case). The size of bone defect was 1-5 cm. Bone defect was repaired with cancellous granule-type calcium phosphate cement (1-5 g). Results All cases were followed up 8-23 months (13.7 months on average). Thirty-nine incisions (32 cases) healed by first intention and the suture was removed after 10-14 days. Incision dehiscence occurred in 2 cases, and wounds healed after second debridement and removal of artificial bone. Exudation of incision occurred in 1 case, and wound healed after symptomatic treatment. No local red swell ing, higher temperature, maculopapule, and ulceration of skin occurred at implantation site. X-ray films showed that bone graft fusion was achieved and bone defect was radically repaired at 6 months after operation and artificial bone was absorbed completely at 12 months. Conclusion Cancellous granule-type calcium phosphate cement can be used as a new graft bone material, which is suitable for defect fill ing after traumatic fracture, benign bone tumors, and il iac bone donor.
ObjectiveTo investigate the effects of micro/nano-structure and antimicrobial peptides (AMPs) on antibacterial properties of titanium (Ti) metallic surface.MethodsTi disks were treated via sandblasted large-grit acid-etched (SLA) and alkali-heat treatment (AHT) to build the micro/nano-structure, on which AMPs were spin-coated with a certain amount (10, 30, 50, 70, and 90 μg). Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were used to observe the surface structure and characterize the surface elements (i.e. contents of C, N, O, and Ti). Ti disks loaded with AMPs of difference amounts were co-cultured with Staphylococcus aureus (S. aureus) for 24 hours. After that, the formation and dimension of antibacterial circle were measured. Furthermore, the Ti disks treated with different approaches (untreated, SLA treatment, SLA+THA treatment, and 90 μg AMPs-loaded samples) were co-cultured with S. aureus and Escherichia coli (E.coli) for 3 hours, bacterial adhesion on the disks were evaluated by using SEM. The antibacterial performances in solution were quantitatively evaluated by immersing the Ti disks in bacterial solutions and measuring the absorbance (A) values.ResultsIt was found that the nanoporous structure could be easily constructed by SLA+AHT approach. After spin-coating AMPs, the nanopores with the diameter less than 200 nm were almost covered. According to the element analysis, with the increase of AMPs, the C content gradually increased; the N content was not detected until AMPs amount reached 70 μg on the disks. The diameter of antibacterial circle clearly depended on the AMPs amount. The Ti disks loaded with 90 μg AMPs had significantly larger antibacterial circles than the other Ti disks (P<0.05). Based on the SEM observation, the Ti disks loaded with 90 μg AMPs has the least bacterial attachment compared with the other Ti disks (P<0.05). TheA value of bacterial solution immersed with the Ti disks loaded with 90 μg AMPs was much lower than the other Ti disks (P<0.05).ConclusionThe approach of micro/nano-structure and AMPs can improve the antibacterial properties of Ti metallic surface.
Objective To investigate the cl inical appl ication of self-setting CPC loading rhBMP-2 for repair of bone defects and to evaluate the cl inical effect and safety. Methods From June 2006 to September 2007, 112 bone defects patients were treated by CPC loading rhBMP-2 (rhBMP-2/CPC group) or CPC (control group). The range of bone defect was from1 cm × 1 cm × 1 cm to 4 cm × 3 cm × 3 cm. In the control group, 63 patients included 31 males and 32 females, aging from 17 to 70 years with an average of 47.4 years. The bone defects were located as follows: calcaneus in 19 patients, tibial plateau in 20 patients, proximal humerus in 8 patients, distal radius in 9 patients and thoracolumbar vertebrae in 7 patients. In the rhBMP-2/CPC group, 49 patients included 31 males and 18 females, aging from 16 to 68 years with an average of 45.6 years. The bone defects were located as follows: calcaneus in 11 patients, tibial plateau in 16 patients, proximal humerus in 7 patients, distal radius in 2 patients, distal tibia in 2 patients and thoracolumbar vertebrae in 11 patients. All defects were repaired with rhBMP-2/CPC (2-5 g) and CPC (2-50 g) in the rhBMP-2/CPC group and the control group, respectively. Results A total of 108 patients got primary heal ing after operation. Incisions oozing l ight yellow fluids were found in 4 patients (control group in 1, rhBMP-2/CPC group in 3), and then healed through dressing changes and taking glucocorticoid. There were no allergic or toxic reaction, no rush or high fever, no fluctuation of hepatic and renal function, blood routine, CRP and urine routine. All patients were followed up for 12 to 24 months (mean 13.2 months). The X-ray examination showed that the implanted material was firmly bonded to the bone at the interface and the anatomic contour of the bone at the sites of defects was successfully restored, and no ablation occurred. All patients got bone union after 3 months of operation. The movement and function of flexion and extension of affected l imbs recovered to the normal level. Conclusion Repairing bone defects with rhBMP-2/CPC is safe and effective. Using rhBMP-2/CPC is a promising therapy to deal with bone defects.
Objective To access the possibil ity of CPC as a suitable scaffold for tissue engineering artificial rib by morphologic observation, adhesion experiments and cellar prol iferation experiments. Methods The 5 mm × 5 mm × 5 mm CPCs were prepared and the structure and components of CPC were compared with those of the normal human bone by micro-CT and scanning electron microscope. Bone marrow aspirates were harvested from the young pig and monuclear cells were separated. The first passage cells were collected and re-suspended in the culture media at a density of 6 × 105 cells/mL. There was 150 μL suspension which was incoluated on the CPC, and then cells were recollected and counted 4, 12 and 24 hours after inoculation. MTT was used to examine the growth condition of BMSCs on the surface of CPC. The scanning electron microscope was used to observe the CPC scaffold 7 days after inoculation, and comparison was made with CPC and the normal human bone. Results The adhesion rate of CPC was 28.00% ± 0.98%, 46.70% ± 1.14% and 48.50% ± 1.18%, respectively 4, 12 and 24 hours after compound culture. The prol iferation rate of CPC was 1.103 ± 0.214, 1.557 ± 0.322, 1.920 ± 0.178, 2.564 ± 0.226, 2.951 ± 0.415 and 3.831 ± 0.328, respectively 1, 2, 3, 4, 5 and 6 days after compound culture, with an obvious rising trend. The micro-CT demonstrated that the content of hydroxyapatite of porous phosphate calcium was (1 101.222 8 ± 0.618 4) mg/ ccm while that of the normal human bone was (1 072.552 3 ± 0.744 2) mg/ccm, and the porosity of porous phosphate calcium was 70.26% ± 0.45% while that of the normal human bone was 72.82% ± 0.51%, and there was no significant difference (P gt; 0.05). The experiment of cell prol iferation showed that the cell which was cultivated with porous phosphate calcium prol iferated rapidly. Through the inverted phase contrast microscope, it was found that the cells grew well and there was no dead cell, which indicated that the material had no toxicity. The rate of the cell adhesion to CPC was less than 50%. Conclusion The structure and components of CPC are similar to those of the normal human bone, and BMSCs grow well on the surface of it, so it is asuitable scaffold for tissue engineering artificial rib. However, the cell adhesion abil ity is to be further improved.
Objective To investigate the effect of rhBMP-2 combined with porous CPC on spine fusion in rabbits. Methods rhBMP-2 (1 mg) was loaded with 1 g CPC and 6.0 cm × 2.0 cm × 0.5 cm absorbable gelatin sponge (AGS), respectively, and thereafter frozen to prepare the biomaterial of rhBMP-2/CPC and rhBMP-2/AGS. Forty-five 24-week-old New Zealand rabbits (weight 2.5-3.5 kg) were randomly divided into 3 groups: group A (n=17), group B (n=11) and group C (n=17).With the exposure and removal of L5, 6 transverse process’s posterior bone cortex in all the rabbits, the corresponding cancellous bones were exposed and the posterior bilateral intertransverse bone grafting of L5, 6 were performed on the three groups, then the rhBMP-2/CPC, rhBMP-2/AGS and CPC was implanted into the rabbits of group A, B and C, respectively. Gross observation, histology assay and image examination were conducted 4, 8 and 24 weeks after operation. Results Decalcified hard tissue section demonstrated obvious callus connections in group A, small pieces of callus in group B, and fibrous connection and few cartilage in group C at 4 and 8 weeks after operation. By Kacena measurement standard, the score of group A, B and C at 4 weeks after operation was (7.30 ± 0.76), (3.68 ± 1.60) and (1.75 ± 0.54) points, respectively, and their score at 8 weeks after operation were (8.32 ± 1.11), (3.75 ± 1.23) and (1.47 ± 0.23) points, respectively, indicating there were significant differences between group A and group B as well as between group A and group C at different time points (P lt; 0.05). Undecalcified hard tissue section demonstrated that there was cancellous bone-l ike tissue regeneration in group A, and fiber connection around the implants and l ittle ossification in group C at 4 and 8 weeks after operation. By three dimensions reconstructed CT, group A, B and C scored (2.50 ± 0.57), (1.00 ± 0.00) and (1.00 ± 0.00) points respectively, indicating there was a significant difference between group C and groups A and B as well as between group A and group B (P lt; 0.05). Conclusion As a carrier of rhBMP-2, the CPC is capable of promoting spine bone fusion in rabbits and is a new type of artificial bone repair material.