Objective To study the methods of promoting the injectability of calcium phosphate cement.Methods Evaluation methods of bone cements, injectability and methods of promoting injectability were reviewed by extensive investigating of latest literatures.Results It was very important to improve the injectability of calcium phosphate cement. Commonly used methods to evaluate the injectability included testing injectability coefficient, pushing force and injection pressure.Injectability of calcium phosphatecement were promoted by increasing liquid/solid ratio, modulating the componentof solid or liquid phase, and adding various additives.Conclusion Promoting the injectability of calcium phosphate cement is the clinical requirement.
The aim of this experiment was to study the osteogenesis in vivo of allogenic osteoblast combined culture with calcium phosphate composites. The osteoblasts were obtained by enzymatic digestion of periosteum from fibula subcultured to 13 generations, the cells were combined culture with hydroxyapatite and biphasic calcium phosphate. Subseguently, the composite was implanted into rabbits subcutaneously or intramuscularly. The blank material was implanted in the contralateral side as control. Four weeks later, all animals were sacrificed. All the implants were examined by gross observation, histological examination and EDXA. The results showed: 1. obvious ingrowth of connective tissue with very little inflammatory reaction; 2. new bone formation in the composites with deposit of Ca and P on the surface of osteoblast, but none in the blank materials; 3. no significant difference of new bone formation between the different sites of implantation or different materials, but those implanted intramuscularly had lamellae form of new bone while those implanted subcutaneously had only mineralization of extracellular matrix. The conclusion were: 1. the composites are biocompatible with prior osteogenesis property; 2. periosteal-derived allogenic osteoblasts obatined by enzymatic digestion could survive following implantation with bioactivity; 3. rich blood supply might be advantageous to new bone formation and its maturation.
Objective To investigate the physicochemicalproperties of the calcium phosphate cement (CPC) containing Danshen composite injection and its drug release rate. Methods This experiment included 4 groups and each group contained 6 specimens. CPC (2 g) was mixed with the setting solution that served as thecontrol group; 0.1,0.5 and 1.0 ml of Danshen composites injection (concentration, 1 000 mg/ml; pH, 7.35) were respectively added to CPC (2 g), which were used as the experimental groups 1, 2 and 3. The resulting specimens were investigated by the X-ray diffraction (XRD), the fourier transformed infrared spectroscopy(FTIR), and the scanning electron microscope (SEM).ResultsThe XRD analysis showed that the control group had a typical diffraction pattern of the hydroxypatite (HAP), which was consistent with the standard patternof HAP. When more Danshen was added in the experimental groups, the diffractionpeaks of HAP gradually decreased; when the diffraction angle 2θ was about 25.92°, the HAP peaks disappeared. Based on the FTIR analysis, with an increase of the drug concentration, the absorption peak of the hydroxy groups decreased. The SEM showed that the size of the CPC particle was related to the drug concentration; with an increase of the drug concentration, the CPC particle increased in number, resulting in an increasing trend of coacervation. The elution test showed that the drugrelease rate and capacity varied with the different concentrationsof Danshen. The initial release rate was relatively great, but after 96 hours the rate slowed down, lasting for a long time. Conclusion The physicochemical properties of CPC do not change when a proper dose (0.1 ml/2 g) of Danshen isadded to CPC. The Danshen composite can be effectively released from CPC, and so CPCcan be used as an ideal drugdelivery carrier for Danshen composite.
Objective To investigate the in vivo degradable properties of new calcium phosphate cement (CPC) containing poly lactic-co-glycolic acid (PLGA) so as to lay a foundation for the future clinical application. Methods A novel CPC containing PLGA (CPC/PLGA) was prepared according to a ratio of 45% dicalcium phosphate anhydrous ∶ 45% partially crystallized calcium phosphates ∶ 10% PLGA. Thirty-two adult New Zealand rabbits (weighing 2.2-3.0 kg, male or female in half) were divided into the experimental group (n=17) and the control group (n=15). The bone defect models of the bilateral femoral condyles (4.5 mm in diameter and 1.5 cm in depth) were made by drilling hole. Defect at the right side was repaired with CPC/ PLGA in the experimental group and with CPC in the control group, while defect at the left side was not treated as blank control. The general condition of rabbits was observed after operation; the histological observation and bone histomorphometric analysis were performed at 2, 4, 8, 16, and 24 weeks; and scanning electronic microscope (SEM) observation was performed at 8 and 16 weeks after operation. Results All rabbits survived to the end of experiment. The histological observation showed: CPC/PLGA degraded gradually, and the new-born bone trabecula ingrew; bone trabeculae became rough and b; and CPC/PLGA almost biodegraded at 24 weeks in the experimental group. The CPC degradation was much slower in the control group than in the experimental group. The total bone tissue percentage was 44.9% ± 23.7% in the experimental group, and 25.7% ± 10.9% in the control group, showing significant difference between 2 groups (t=3.302, P=0.001); and the bone tissue percentage showed significant difference between 2 groups at 8, 16, and 24 weeks (P lt; 0.05). The results of SEM observation showed that the pore size was 100-300 μm at 8 weeks after operation, new-born bone trabecula grew into the pores and combined bly with residual cement in the experimental group. Conclusion Novel CPC/PLGA has good in vivo degradable properties, and it can be an ideal bone substitute in future clinical application.
Objective To find out an effective technique torepair large segmental infected bony defect.Methods Calcium phosphate cement(CPC) incorporated with bone morphogenetic protein and gentamycin was embedded in the massive reconstituted bovine xenograft(MRBX), then CPC-MRBX was obtained after CPC’s solidification. In vivo test was applied to test the drug delivery capability of CPC-MRBX, in which it was implanted in the dorsal muscle pouch of 18 rabbits. The drug concentration of animal blood and surrounding soft tissue of the CPC-MRBX in the muscle pouch was measured 1, 2, 5, 10, 15, 20, 25, 30 and 35 d after operation, 2 rabbits each time. Large segmental infected femur defect in the rabbit model was created to test the repairing capability of CPC-MRBX. External fixation was done 1.5~2.0 cm above the knee, the most adjacent nail to fracture site was 0.5～0.8 cm away, and proper pressure was applied to the graft. In experimental group(n=25), the bony defect was replaced by CPC-MRBX, while in the control group(n=15) dissected bone block was re-implanted in original position. The animal was subjected to radiographic, histological examination at 4, 8, 16 and 24 weeks. The general condition was observed after the operation.Results CPC-MRBX was easily made under normal temperature and pressure. In viro drug delivery test showed that the drug concentration of the tissue remainedabove the minimal inhibitory concentration of staphylococcus 30 d after operation and no significant increase of blood drug concentration was observed. In experimental group, no adverse influence was observed. Four weeks after operation, the animal could bear load, bony callus around the graft was observed by X-ray, and abundant chondral tissues that grew into CPC-MRBX were observed by histological method. Eight weeks after operation, progressively increasing bony callus around the graft was observed, external fixation could be removed, normal function was restored, and CPC was degenerated dramatically while new bone tissues were growing. Sixteen weeks after the operation, more new bone tissues grew and CPC was degenerated furtherly while marrow tissues were taking shape. Twenty-four weeks after the operation, femur healed completely and CPC was degenerated completely. In the control group, the autograft remained unhealedon X-ray at 4 weeks, and osteomyelitis manifestation such as inflammatory cells infiltration and osteolysis was detected at 4 weeks. All the animals in the control group died before the 8th week, 4 of which showed positive hemoculture. Conclusion CPC-MRBX is readily available and can be applied to repairing large segmental infected bony defect.30 d after operation and no significant increase of blood drug concentration was observed. In experimental group, no adverse influence was observed. Four weeks after operation, the animal could bear load, bony callus around the graft was observed by X-ray, and abundant chondral tissues that grew into CPCMRBX were observed by histological method. Eight weeks after operation, progressively increasing bony callus around the graft was observed, external fixation could be removed, normal function was restored, and CPC was degenerated dramatically while new bone tissues were growing. Sixteen weeks after the operation, more new bone tissues grew and CPC was degenerated furtherly while marrow tissues were taking shape. Twenty-four weeks after the operation, femur healed completely and CPC was degenerated completely. In the control group, the autograft remained unhealedon X-ray at 4 weeks, and osteomyelitis manifestation such as inflammatory cells infiltration and osteolysis was detected at 4 weeks. All the animals in the control group died before the 8th week, 4 of which showed positive hemoculture.Conclusion CPC-MRBX is readily available and can be applied to repairing large segmental infected bony defect.
Objective To explore the clinical efficiency of vancomycin-loaded calcium phosphate cement (CPC) in the treatment of chronic osteomyelitis (CO). Methods From December 1st 2014 to December 1st 2015, 98 patients with CO were randomly divided into the research group and the control group, with 49 in each group. The patients in the research group were primarily implanted with vancomycin-loaded CPC after debridement, while the ones in the control group were placed with irrigation and drainage device to take continous irrigation with antibiotics after debridement. The treatment effect and the recurrence rate in the two groups were observed. Results The patients in the two groups were followed up for 12 months. In the research group, 30 patients were cured, 16 were improved, and 3 were not improved with the total effective rate of 93.9%; no systemic adverse reactions and recurrence took place after the operation; X-ray results showed well CPC tamponade and partially degenerated osteogenesis. In the control group, 16 patients were cured, 20 were improved and 13 were not improved, with the total effective rate of 73.5%; 11 had recurrent inflammation in 2–6 months after operation and were reoperated again. Conclusion The primary implantation of vancomycin-loaded CPC in CO lesions can fill the dead space, resist infection persistently, induce osteogenesis in bone defect area, and reduce the recurrence of CO, which is an effective method for the treatment of CO.
Objective To study the mechanism of compound of calcium phosphate(TCP) and platelet-rich plasma(PRP) in the treatment of femoral head necrosis.Methods The left femoral heads of 48 New Zealand white rabbits were frozen by liquid nitrogen as to make themodel of femoral head necrosis.Twenty-four rabbits were randomly chosen as theexperimental group and their femoral heads were filled with TCP/PRP. The other 24 rabbits were used as the control group and their femoral heads were filled only with TCP. They were sacrificed at 2, 4,8,12 weeks after operation. The specimens were examined with X-ray and histological study.Results At 2 weeks after operation,there was no significant difference in femoral headdensity between the two groups. Four weeks after operation, femoral head density decreased in both groups, while it decreased more in the control group. At 8,12 weeks after operation, the density of the femoral heads in both groups increased, and it was higher in the experimental group. Histology examination showed thatthere was no difference between the two groups 2 weeks after operation. The head became flat at 4 weeks. Control group had more defects. At 4,8,12 weeks, more repairs were observed in the experimental group than that in the control group. The amount and maturity of osteogenesis in experimental group were much more greaterthan those in control group．Bone histomorphometry showed that the volum of thetrabecular was larger in the experimental group (36.65%±7.22%,38.29%±4.28%，39.24%±3.42%) than that of control group(P＜0.05). Conclusion TCP/PRP does not only provide osteoblasts scaffold, butalso promotes bone formation and the head repair. TCP/PRP is a good biomaterialfor the treatment of femur head necrosis.
Objective To investigate the clinical application of self-settingcalcium phosphate cement (CPC) in bone defect repair of extremities. Methods From May 1998 to January 2000, 32 cases of bone defect, in 36 sites, were repairedand reviewed, aged from 4 to 59 years old (24.7 years old on average), with bone defect 2 to 125 cm2 in size (13.1 cm2 on average). The causes of the bone defect werefracture, bone cyst, iliac bone harvesting, fibrous dysplasia, enchondroma and bone tuberculosis, which involved femur, iliac, tibia, humerus, phalanx, fibula, calcaneus, talus and acetabulum. All of the cases were followed up for 1 to 23 months, 15.3 months on average, before radiographic examination. Results All operations were successful and no general response was observed in all of the cases. X-ray examination showed an integrity interface between CPC and bone. And CT showed no gap existed. There was no increase of serum calcium and phosphate levels. Conclusion CPC is applicable in the low- or non-weight-bearing site of the extremities.
ObjectiveTo investigate the mechanical properties of the novel compound calcium phosphate cement (CPC) biological material as well as the biological activity and osteogenesis effects of induced pluripotent stem cells (iPS) seeding on scaffold and compare their bone regeneration efficacy in cranial defects in rats.MethodsAc- cording to the different scaffold materials, the experiment was divided into 4 groups: pure CPC scaffold group (group A), CPC∶10%wt chitosan as 2∶1 ratio mixed scaffold group (group B), CPC∶10%wt chitosan∶whisker as 2∶1∶1 ratio mixed scaffold group (group C), and CPC∶10%wt chitosan∶whisker as 2∶1∶2 ratio mixed scaffold group (group D). Mechanical properties (bending strength, work-of-fracture, hardness, and modulus of elasticity) of each scaffold were detected. The scaffolds were cultured with fifth generation iPS-mesenchymal stem cells (MSCs), and the absorbance (A) values of each group were detected at 1, 3, 7, and 14 days by cell counting kit 8 (CCK-8) method; the alkaline phosphatase (ALP) activity, Live/Dead fluorescence staining and quantitative detection, ALP, Runx2, collagen typeⅠ, osteocalcin (OC), and bone morphogenetic protein 2 (BMP-2) gene expressions by RT-PCR were detected at 1, 7, and 14 days; and the alizarin red staining were detected at 1, 7, 14, and 21 days. Twenty-four 3-month-old male Sprague Dawley rats were used to establish the 8 mm-long skull bone defect model, and were randomly divided into 4 groups (n=6); 4 kinds of scaffold materials were implanted respectively. After 8 weeks, HE staining was used to observe the repair of bone defects and to detect the percentage of new bone volume and the density of neovascularization.ResultsThe bending strength, work-of-fracture, hardness, and modulus of elasticity in groups B, C, and D were significantly higher than those in group A, and in groups C, D than in group B, and in group D than in group C (P<0.05). CCK-8 assay showed that cell activity gradually increased with the increase of culture time, theA values in groups B, C, and D at 3, 7, 14 days were signifiantly higher than those in group A, and in groups C, D than in group B (P<0.05), but no significant difference was found between groups C and D (P>0.05). Live/Dead fluorescence staining showed that the proportion of living cells in groups B, C, and D at 7 and 14 days was significantly higher than that in group A (P<0.05), and in groups C, D at 7 days than in group B (P<0.05); but no significant difference was found between groups C and D (P>0.05). RT-PCR showed that the relative expressions of genes in groups B, C, and D at 7 and 14 days were significantly higher than those in group A, and in groups C, D than in group B (P<0.05); but no significant difference was found between groups C and D (P>0.05). Alizarin red staining showed that the red calcium deposition on the surface of scaffolds gradually deepened and thickened with the prolongation of culture time; theA values in groups B, C, and D at 14 and 21 days were significantly higher than those in group A (P<0.05), and in groups C and D than in group B (P<0.05), but no significant difference was found between groups C and D (P>0.05).In vivo repair experiments in animals showed that the new bone in each group was mainly filled with the space of scaffold material. Osteoblasts and neovascularization were surrounded by new bone tissue in the matrix, and osteoblasts were arranged on the new bone boundary. The new bone in groups B, C, and D increased significantly when compared with group A, and the new bone in groups C and D was significantly higher than that in group B. The percentage of new bone volume and the density of neovascularization in groups B, C, and D were significantly higher than those in group A, and in groups C and D than in group B (P<0.05); but no significant difference was found between groups C and D (P>0.05).ConclusionThe mechanical properties of the new reinforced composite scaffold made from composite chitosan, whisker, and CPC are obviously better than that of pure CPC scaffold material, which can meet the mechanical properties of cortical bone and cancellous bone. iPS-MSCs is attaching and proliferating on the new reinforced composite scaffold material, and the repair effect of bone tissue is good. It can meet the biological and osteogenic activity requirements of the implant materials in the bone defect repair.
Objective Calcium phosphate bioceramics has a broad appl ication prospect because of good biocompatibil ity, but porous scaffolds with complex shape can not be prepared by the traditional methods. To fabricate porous calcium phosphate ceramics by rapid prototyping and to investigate the in vitro osteogenic activities. Methods The porous calcium phosphate ceramics was fabricated by rapid prototyping. The bone marrow mesenchymal stem cells (BMSCs)were isolated from bone marrow of Beagle canine, and the 3rd passage BMSCs were seeded onto the porous ceramics. The cell/ceramics composite cultured in osteogenic medium were taken as the experimental group (group A) and the cell/ceramics composite cultured in growth medium were taken as the control group (group B). Meanwhile, the cells seeded on the culture plate were cultured in osteogenic medium or growth medium respectively as positive control (group C) or negative control (group D). After 1, 3, and 7 days of culture, the cell prol iferation and osteogenic differentiation on the porous ceramics were evaluated by DNA quantitative analysis, histochemical staining and alkal ine phosphatase (ALP) activity. After DiO fluorescent dye, the cell adhesion, growth, and prol iferation on the porous ceramics were also observed by confocal laser scanning microscope (CLSM). Results DNA quantitative analysis results showed that the number of BMSCs in all groups increased continuously with time. Plateau phase was not obvious in groups A and B, but it was clearly observed in groups C and D. The CLSM observation indicated that the activity of BMSCs was good and the cells spread extensively, showing good adhesion and prol iferation on the porous calcium phosphate ceramics prepared by rapid prototyping. ALP quantitative analysis results showed that the stain of cells on the ceramics became deeper and deeper with time in groups A and B, the staining degree in group A were ber than that in group B. There was no significant difference in the change of the ALP activity among 4 groups at the first 3 days (P gt; 0.05); the ALP activity increased obviously in 4 groups at 7 days, group A was significantly higher than other groups (P lt; 0.05) and groups C, D were significantly higher than group D (P lt; 0.05). Conclusion The porous calcium phosphate ceramics has good cytocompatibil ity and the designed pores are favorable for cell ingrowth. The porous ceramicsfabricated by rapid prototyping has prominent osteogenic differentiation activity and can be used as a choice of scaffolds for bone tissue engineering.