OBJECTIVE: To investigate the feasibility of coralline hydroxyapatite (CHA) as scaffolds in bone tissue engineering. METHODS: The bone marrow stromal cells from 4-month New Zealand rabbits were harvested and cultured in vitro. After multiplied, dexamethasone was used to promote the osteoblastic phenotype of the cells. The cells were harvested and then seeded into CHA. By means of tissue engineering technique, osteoblastic cells/CHA complex were formed. The complex were implanted subcutaneously in nude mice. The CHA alone was implanted as control. Bone regeneration was assessed 6, 8 weeks after implantation by histological and roentgenographic analysis. RESULTS: After six weeks of implantation, x-ray film showed high-density signal, osteoid tissue formed under histological examination. Large amount of new bone were formed and connected to trabecularism 8 weeks after implantation in the experimental group. While in the control group, there were no new bone formation, but amount of fiber tissue grew into the pore of CHA 8 weeks after implantation. CONCLUSION: CHA may be used as a good scaffold material for bone tissue engineering.
Objective Titania and Ag containing nano-hydroxyapatite/polyamide 66 (TiO2-Ag-nHA/PA66) composite bone fill ing material has good biocompatibil ity and biological safety. To investigate the antibacterial effect and Ag+ release characteristics of TiO2-Ag-nHA/PA66 composite bone fill ing material containing different concentrations of Ag+ in vitro. Methods The n-HA/PA66 composite bone fill ing material A1 (material A1) was prepared by co-polymerization method, and TiO2-Ag-nHA/PA66 composite bone fill ing materials A2 and A3 (materials A2 and A3) were prepared by thesame way containing Ag+ of 0.22wt% and 0.64wt%, respectively, and the TiO2 content was 2.35wt%. The materials A2 and A3 were respectively immersed in 50 mL simulated body fluid (SBF), and Ag+ concentration was measured by atomic absorption spectrometry at 1, 3, 7, 14, 21, and 49 days. The inhibition ring test and colony count method were used to evaluate antibiotic effect against Staphylococcus aureus and Escherichia coli, the anti-adhesion capacity of Staphylococcus aureus and Escherichia coli was observed by scanning electron microscope (SEM). Results There was no significant difference in the Ag+ concentration between materials A2 and A3 at 1 day and 3 days (P gt; 0.05); and there were significant differences in the Ag+ concentration between materials A2 and A3 after 7 days (P lt; 0.05). The inhibition ring diameters of materials A2 and A3 to Staphylococcus aureus and Escherichia coli reached the maximum at 1 day, which were (13.40 ± 2.88), (9.40 ± 1.14) mm and (23.60 ± 1.14), (18.80 ± 0.84) mm, showing significant difference (P lt; 0.05) between materials A2 and A3 respectively; and then, the diameter of inhibition ring reduced with the time. The antibacterial effect of materials A2 and A3 against Staphylococcus aureus and Escherichia coli lasted 15, 33 days and 9, 24 days, respectively. No inhibition ring was observed around material A1 all the time. And the inhibitory rates of materials A2 and A3 were 89.74% ± 3.62%, 94.18% ± 2.05% and 78.65% ± 5.64%, 85.96% ± 2.50%; showing significant differences (P lt; 0.05) among materials A1, A2, and A3. SEM showed that bacterial adhesion of materials A2 and A3 was obviously fewer than that of material A1. Conclusion TiO2-Ag-nHA/PA66 composite bone fill ing material has antibacterial property against Staphylococcus aureus and Escherichia coli, and it has a good release effect in SBF.
ObjectiveTo compare the biomechanical differences between the kidney-shaped nano-hydroxyapatite/polyamide 66 (n-HA/PA66) Cage and the bullet-shaped n-HA/PA66 Cage. MethodsL2-L5 spinal specimens were selected from 10 adult male pigs. L2, L3 and L4, L5 served as a motor unit respectively, 20 motor units altogether. They were divided into 4 groups (n=5):no treatment was given as control group (group A); nucleus pulposus resection was performed (group B); bullet-shaped Cage (group C), and kidney-shaped Cage (group D) were used in transforaminal lumbar interbody fusion (TLIF) through left intervertebral foramen and supplemented by posterior pedicle screw fixation. The intervertebral height (IH) and the position of Cages were observed on the X-ray films. The range of motion (ROM) was measured. ResultsThere was no significant difference in the preoperative IH among 4 groups (F=0.166, P=0.917). No significant change was found in IH between at pre- and post-operation in group B (P>0.05); it increased after operation in groups C and D, but difference was not statistically significant (P>0.05). There was no significant difference in the postoperative IH among groups B, C, and D (P>0.05). The distance from Cage to the left margin was (3.06±0.51) mm in group C (close to the left) and (5.68±0.69) mm in group D (close to the middle), showing significant difference (t=6.787, P=0.000). The ROM in all directions were significantly lower in groups C and D than in groups A and B (P<0.05), and in group A than in group B (P<0.05). The right bending and compression ROM of group C were significantly higher than those of group D (P<0.05), but no statistically significant difference was found in the other direction ROM (P>0.05). ConclusionThe bullet-shaped and kidney-shaped Cages have similar results in restoring IH and maintaining the stability of the spine assisted by internal fixation. Kidney-shaped Cage is more stable than bullet-shaped Cage in the axial compression and the bending load opposite implant, it can be placed in the middle and back of the vertebral body more ideally.
Objective To investigate the ability of repairing bone defect with the compound of recombinant human insulinlike growth factor 1 (rhIGF-1), coralline hydroxyapatite(CHA) and autogeneous red bone marrow(ARBM), and to study the feasibility of the compounds being used as bone substitute materials. Methods Bilateral radius bone defects(11 mm in length) were created in 54 Chinese rabbits,which were randomly divided into 3 groups, and two different materials were randomly transplanted into the bilateral defects:in group 1, with material A(rhIGF-1/CHA/ARBM) and material B(CHA/ARBM); in group 2, with material C(rhIGF-1/CHA) and material D(CHA); in group 3, with E(autograft) and F(no implant) as controls. At 2, 4, 8 and 12 weeks, the effects were assessed by X-ray andimage analysis, biomechanics(at 12 weeks), as well as histological observation. Results X-ray and image analysis showed that material A of group 1was significantly superior to any other materials(P＜0.01). Antibending biomechanic detection showed that material A and Ewas significantly superior to the other materials(Plt;0.01), but no significant difference was found between A and E in the 12th week(Pgt;0.05). And by histological observation, in analogical bone morphological progress, materials C and D obviously inferior to materials A, B and E, but there was no significant difference between materials C and D. F had no evidence of new bone rebridging. Conclusion The recombinant compound CHA/ARBM(rhIGF-1),which posseses the potential ability of osteogenesis,osteoconduction and osteoinduction for bone defect repairing,can serve as a new type of autogenous bone substitute material.
Objective To retrospectively analyze the cl inical effect of l ightbulb operation with nano-hydroxyapatite/ collagen in a consecutive series of patients with osteonecrosis of the femoral head (ONFH). Methods From January 2001to July 2005, 26 patients (35 hips) were treated, 16 males and 10 females, aged 19-54 years old (33.5 on average). The course of disease was 12-36 months (18 months on average). Based on the etiology, 15 cases (22 hips) were steroid induced type, 10 (12 hips) were alcohol induced type and the other one (1 hip ) was idiopathic type. According to the system of Association Research Circulation Osseous (ARCO), there were 6 hi ps of stage IIB, 16 hi ps of stage IIC, 9 hi ps of stage IIIA, 3 hi ps of stage IIIB and 1 hip of stage IIIC. The Harris score was 62.2 ± 7.5. All the patients who had undergone l ightbulb operation with nano-hydroxyapatite/collagen were evaluated both cl inically and radiographically. The bone graft mixture rate of nanohydroxyapatite/ collagen and autogenous bone was 1 ∶ 1, and the mixed bone graft was 6 times of the scraped osteonecrosis volume (30-48 mL). Results The incisions of all 26 patients (35 hi ps) obtained heal ing by first intention. The 2 cases, which got lateral femoral cutaneous nerve injury during the operation, recovered 3-6 months after the operation without any treatment. Another 2 cases got heterotopic ossification 3 months after operation, with no special treatment. All the 26 patients (35 hips) were followed up for 2-7 years (3.5 on average). The patients’ bone heal ing began from the 3rd month after operation. The postoperative Harris score was 85.1 ± 16.2, and there was significant difference compared with the preoperative one (P lt; 0.001). There were 15 hips of excellent, 11 of good, 5 of fair, and 4 of poor which received total hip arthroplasty at the end of the follow-up. According to imaging, 5 hips were progressed from preoperative IIC to IIIA, while the other hips were radiologically stable, with no progress of ONFH. Conclusion Lightbulb operation with nano-hydroxyapatite/collagen provides a surgical treatment to treat early ONFH with satisfactory cl inical outcomes. Nano-hydroxyapatite/collagen is beneficial for the repair and reconstruction of ONFH and suitable for femoral-head-preserving operation for the patients with ONFH of stage II.
Objective To investigate the preparation and properties of the novel silica (SiO2)/hydroxyapatite (HAP) whiskers porous ceramics scaffold. Methods The HAP whiskers were modified by the SiO2 microspheres using the Stöber method. Three types of SiO2/HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO2/HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO2/HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics. Results The SiO2 microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO2/HAP whiskers, the amorphous SiO2 microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO2/HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO2/HAP whisker porous ceramic was the highest. The SiO2 microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO2 microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity. Conclusion SiO2/HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
OBJECTIVE: To investigate the ability of repairing bone defect with the compound of coralline hydroxyapatite porous (CHAP), fibrin sealant(FS) and staphylococcus aureus injection (SAI), and the feasibility to use the compounds as bone substitute material. METHODS: The animal model of bone defect was made on the bilateral radius of 54 New Zealand white rabbits, which were randomly divided into the experimental group(the defect was repaired with CHAP-FS-SAI), control group(with autograft) and blank control group(the defect was left unrepaired) with 18 rabbits in each group. The ability of bone defect repair was evaluated by gross observation, histopathological study, X-ray and biomechanical analysis 2, 4, 8 and 12 weeks after repair. RESULTS: (1) In the 2nd week, tight fibro-connection could be found between the implant and fracture site and there were many fibroblasts and capillary proliferation with many chondrocytes around CHAP in the experimental group, while only a few callus formed, and chondrocytes, osteoblast and osteoclast existed in the control group. (2) In experimental group and control group, a large quantity of callus was found 4 and 8 weeks; ossification of chondrocytes with weave bone formation were found 4 weeks and many osteocytes and weave bones and laminar bones were found 8 weeks. (3) In the 12th week, the complete ossification of implant with well bone remodeling, a large number of mature osteocytes and laminar were found in experimental group and control group, and CHAP still existed in the experimental group; the defect area filled with fibro-scar tissue and only many fibroblasts could be seen in blank control group. (4) X-ray findings were the following: In experimental and control groups, callus formation could be seen 2 weeks postoperatively, more callus formed 4 weeks, the bone defect area disappeared and CHAP scattered in the callus 8 weeks; the fracture line disappeared and medullary cavity became united (in control group); and in the 12th week, the cortex became continuous, the medullary cavity became united, and remodeling completed, while bone defect was not still united in blank control group. The maximal torque and torsional stiffness in the experimental group is higher than those in the control group 2 weeks (P lt; 0.05), but there was no significant difference (P gt; 0.05) between the two groups 4, 8, 12 weeks after repair. CONCLUSION: The compound of CHAP-FS-SAI has good biological compatibility, and it can be used for one kind of bone substitute material to repair the bone defect.
This study aims to explore the vascularization of hydroxyapatite/tricalcium phosphate (HA/TCP) biomaterials implanted in mice during osteoinduction. The HA/TCP biomaterials were implanted in muscle of mice, and 2, 4, 6, 8, 10 and 12 weeks after the implantation, the materials were harvested to prepare serial sections and hematoxylin-eosin (HE) staining. The process of vascularization was dynamically described, and the area percentage of neovascularization was quantitatively analyzed. The results showed that neovascularization formation was a continuous and dynamic process. The neovascularization appeared largely in the first two weeks, with a rising trend in week 4, reached peak in week 6, and gradually reduced in week 8. The results provide ideas for improving the success rate of bone tissue engineering, and indicate the mechanism of osteoinduction.
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 evaluate the security and effectiveness of nano-hydroxyapatite/polyamide 66 (n-HA/PA66) cage in reconstruction of spinal stabil ity after resection of spinal tumor. Methods Between January 2008 and December2009, 11 patients with spinal tumor underwent surgical resection and strut graft with n-HA/PA66 cage. There were 6 males and 5 females with an average age of 44.5 years (range, 16-61 years). The average disease duration was 6.8 months (range, 2-14 months). The locations of lesions included cervical spine (2 cases), thoracic spine (6 cases), and lumbar spine (3 cases). Among them, there were 5 metastatic carcinomas, 2 giant cell tumors, 1 osteoblastsarcoma, 1 chondrosarcoma, and 2 non-Hodgkin lymphoma. According to Frankel criteria for nerve function classification, there were 1 case of grade A, 3 cases of grade B, 2 cases of grade C, 2 cases of grade D, and 3 cases of grade E. Results Incisions healed by first intention in all patients, no operative or postoperative compl ication occurred. Four cases of metastatic carcinoma died of primary disease during 5-9 months after operation. Seven cases were followed up 14.4 months on average (range, 10-18 months). All patients gained significant improvement of the neurological function at 3 months after operation. All cases obtained bone fusion and good spinal stabil ity without displacement and subsidence of the n-HA/PA66 cage. The intervertebral height of the adjacent segments was (110.5 ± 16.1) mm at 3 months after operation and (109.4 ± 16.2 ) mm at the final follow-up, showing significant differenecs when compared with the preoperative height [(97.5 ± 15.4) mm, P lt; 0.05], but no significant difference between 3 months after operation and the final follow-up. In 2 patients undergoing surgery via anterior approach, bilateral pleural effusion on both sides occurred and were cured after closed thoracic drainage. During the follow-up, 2 cases (1 chondrosarcoma and 1 giant cell tumor) relapsed and underwent reoperations. Conclusion n-HA/PA66 cage can provide satisfactory bone fusion and ideal spinal stabil ity without increasing the risk of recurrence and compl ications during the surgical treatment of spinal tumors. It is an idealselection for reconstruction of spinal stability.