【Abstract】 Objective Sonic hedgehog (Shh) signaling pathway is involved in an important part of regulating angiogenesis. To investigate the effects of recombinant Shh N-terminant (rShh-N) on the expression and secretion of angiogenesis-related factor—vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Methods Bone marrow mesenchymal stem scells (BMSCs) were isolated from 3-day-old healthy Sprague Dawley rats and cultured to passage 3 in vitro. rShh-N at the concentrations of 0, 10, 100, and 200 ng/mL were applied to culture BMSCs in groups A, B, C, and D, respectively. At 12, 24, 48, and 72 hours of culture, the expressions of VEGF and bFGF mRNA and the levels of VEGF and bFGF in supernatant were measured with real-time quantitative PCR and ELISA, respectively. Results At the gene level, compared with group A, the expressions of VEGF and bFGF mRNA were enhanced in group D (P lt; 0.05) and the upregulation was more significant at 12 and 48 hours than 24 and 72 hours (P lt; 0.01). In group C, bFGF mRNA expression was substantially promoted at 12-72 hours (P lt; 0.05) and VEGF mRNA level was upregulated at 24-72 hours (P lt; 0.05), and both reached peak at 72 hours (P lt; 0.01). In group B, VEGF mRNA expression was inhibited at 12 hours (P lt; 0.05), but the level increased at 48 and 72 hours (P lt; 0.05); bFGF mRNA expression was obviously promoted at 12-48 hours (P lt; 0.05) and the maximum appeared at 48 hours (P lt; 0.01). At the protein level, the secretion of VEGF and bFGF in group D was significantly increased at 12-72 hours, as compared with group A (P lt; 0.05). In group C, VEGF and bFGF secretion was increased at 24-72 hours (P lt; 0.05). The secretion of VEGF in group B was inhibited at 12 and 48 hours (P lt; 0.05) and was promoted at 24 hours (P lt; 0.05); bFGF secretion was up-regulated at 24 and 48 hours (P lt; 0.05). The secretion of VEGF and bFGF in supernatant at 【Abstract】 Objective Sonic hedgehog (Shh) signaling pathway is involved in an important part of regulating angiogenesis. To investigate the effects of recombinant Shh N-terminant (rShh-N) on the expression and secretion of angiogenesis-related factor—vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Methods Bone marrow mesenchymal stem scells (BMSCs) were isolated from 3-day-old healthy Sprague Dawley rats and cultured to passage 3 in vitro. rShh-N at the concentrations of 0, 10, 100, and 200 ng/mL were applied to culture BMSCs in groups A, B, C, and D, respectively. At 12, 24, 48, and 72 hours of culture, the expressions of VEGF and bFGF mRNA and the levels of VEGF and bFGF in supernatant were measured with real-time quantitative PCR and ELISA, respectively. Results At the gene level, compared with group A, the expressions of VEGF and bFGF mRNA were enhanced in group D (P lt; 0.05) and the upregulation was more significant at 12 and 48 hours than 24 and 72 hours (P lt; 0.01). In group C, bFGF mRNA expression was substantially promoted at 12-72 hours (P lt; 0.05) and VEGF mRNA level was upregulated at 24-72 hours (P lt; 0.05), and both reached peak at 72 hours (P lt; 0.01). In group B, VEGF mRNA expression was inhibited at 12 hours (P lt; 0.05), but the level increased at 48 and 72 hours (P lt; 0.05); bFGF mRNA expression was obviously promoted at 12-48 hours (P lt; 0.05) and the maximum appeared at 48 hours (P lt; 0.01). At the protein level, the secretion of VEGF and bFGF in group D was significantly increased at 12-72 hours, as compared with group A (P lt; 0.05). In group C, VEGF and bFGF secretion was increased at 24-72 hours (P lt; 0.05). The secretion of VEGF in group B was inhibited at 12 and 48 hours (P lt; 0.05) and was promoted at 24 hours (P lt; 0.05); bFGF secretion was up-regulated at 24 and 48 hours (P lt; 0.05). The secretion of VEGF and bFGF in supernatant at
Objective To review the latest researches of synthetic biodegradable polymers for bone repair and reconstruction, to predict the progress of bone substitute materials and bone tissue engineering scaffolds in future. Methods The l iterature concerning synthetic biodegradable polymers as bone substitute materials or bone tissue engineering scaffolds was collected and discussed. Results Al i phatic polyester, polyanhydride, polyurethane and poly (amino acids) were the most extensively studied synthetic biodegradable polymers as bone substitutes and the scaffolds. Each polymer was of good biological safety and biocompatibil ity, and the degradation products were nontoxic to human body. The mechanical properties and degradation rate of the polymers could be adjusted by the type or number of the monomers anddifferent synthetic methods. Therefore, the polymers with suitable mechanical strength and degradation rate could be produced according to the different requirements for bone grafting. Prel iminary studies in vivo showed their favorable capacity for bone repair. Conclusion The synthetic biodegradable polymers, especially the copolymers, composite materials and those carrying bone growth factors are expected to be the most promising and ideal biomaterials for bone repair and reconstruction.
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.
ObjectiveTo review the biological characteristics of self-assembling peptide nanofiber scaffold (SAPNS) and its potential to induce bone repair. MethodsThe literature regarding SAPNS and its application in bone repair was extensively analyzed and reviewed. ResultsSAPNS is derived from natural amino acids, and has the properties of good biocompatibility and non-toxic degradation products. Their microenvironment highly mimics the natural extracellular matrix, and controlled release of growth factors as well as modification with functional motifs can substantially improve their bioactivity. Many studies on cell composite culture and bone defect repair of animal models reveal that SAPNS has the ability to promote the function of bone cells (e.g. adherence, proliferation, and differentiation) in vitro, and enhance new bone tissue formation in vivo. ConclusionSAPNS may be an ideal material for bone repair, but its biologically mechanical properties need further improvement.
ObjectiveTo summarize the research progress of several three-dimensional (3-D) printing scaffold materials in bone tissue engineering. MethodThe recent domestic and international articles about 3-D printing scaffold materials were reviewed and summarized. ResultsCompared with conventional manufacturing methods, 3-D printing has distinctive advantages, such as enhancing the controllability of the structure and increasing the productivity. In addition to the traditional metal and ceramic scaffolds, 3-D printing scaffolds carrying seeding cells and tissue factors as well as scaffolds filling particular drugs for special need have been paid more and more attention. ConclusionsThe development of 3-D printing porous scaffolds have revealed new perspectives in bone repairing. But it is still at the initial stage, more basic and clinical researches are still needed.
Artificial bone repair material is the best substitute for autologous bone transplantation. Bone repair materials are constantly being replaced and upgraded, which can be roughly divided into three generations: bioinert materials, bioactive materials, and smart materials. Research and development of bone repair materials with multiple biological activities, in vivo degradation property that perfectly fit for new bone formation, and ability of complete reconstruction of bone tissue in physiological state are the focus of future research.
Large bone defect repair is a difficult problem to be solved urgently in orthopaedic field, and the application of bone repair materials is a feasible method to solve this problem. Therefore, bone repair materials have been continuously developed, and have evolved from autogenous bone grafts, allograft bone grafts, and inert materials to highly active and multifunctional bone tissue engineering scaffold materials. In this paper, the related mechanism of bone repair materials, the application of bone repair materials, and the exploration of new bone repair materials are introduced to present the research status and advance of the bone repair materials, and the development direction is also prospected.
With high thermal stability, excellent mechanical properties, suitable biocompatibility and radiolucency, polyaryletherketones (PAEKs) have been widely used in biomedical field such as trauma, spinal implants, craniomaxillofacial repair and so on. However, PAEKs are bio-inert in nature and often show weak osteointegration with host bone, limiting their further utilization in biomedical application. Therefore, how to improve the bioactivity and osteointegration of PAEK implants has become the focus in biomedical field. This paper reviews the current research advance and some existed problems in bioactive PAEKs, and outlooks the possible solution.
Sodium alginate (SA) is a kind of natural polymer material extracted from kelp, which has excellent biocompatibility, non-toxicity, biodegradability and abundant storage capacity. The formation condition of sodium alginate gel is mild, effectively avoiding the inactivation of active substances. After a variety of preparation methods, sodium alginate microspheres are widely used in the fields of biomaterials and tissue engineering. This paper reviewed the common methods of preparing alginate microspheres, including extrusion, emulsification, electrostatic spraying, spray drying and coaxial airflow, and discussed their applications in biomedical fields such as bone repair, hemostasis and drug delivery.