Objective To investigate the feasibility of a new kind of porous β tricalcium phosphate (β-TCP) as a scaffold for the bone tissue engineering Methods The inverted phase contrast microscope was used to observe the growth of the marrow mesenchymal stem cells (MSCs) in the experimentalgroup and the control group at 10 days.In the experimental group, the MSCs were cultured with β-TCP(3 mm×3 mm×3 mm) in the 24-hole cultivation board, and in the control to control group, only MSCs were cultivated. The scanning electron microscope was used to observe growth of MSCs at 6 days. Cultivated with β-TCP at 3, 6, 9, 12 days, the MTT assay was used to judge the biocompatibility. The cytotoxicity was analyzed with the method that used the different density(100%， 50%， 10%， 1%，0%) leaching liquor gained from β-TCP to raise MSCs. MSCs were induced into the osteoblasts and were mixed with β-TCP, and the composite was used to repair a large radius bone defect in the rabbit. The specimens were made at 2,6,12 weeks. The histology imageology, and the radionuclide bone scan were used to analyze the bone formation. Results Some MSCs had a good adherence 4 hours after MSCs were inoculated and had a complete adherence at 12 hours. The cells were shaped like polyangle, spindle or converge monolayer after 8-10 days. The cells in the two groups had no difference. The cell adhesion was good, when observed by the inverted phase contrast microscope and the scanning electron microscope at 6 days. MTT showed that the absorbance (A)was not statistically different between the experimental group and the control group (P＞0.05); the different density leaching liquor had no cytotoxicity at the different time points. Histology, X-ray, and CT tomograph showed that itcould repair the large radius bone defect in the rabbit and its in vivo degradationrate was the same as the bone formation rate. Conclusion The new porous β-TCP has a unique three dimensional (3D) stereochemical structure and superordinary physicochemical property, and so it is a good scaffold for the bone tissue engineering.
Objective To review the research progress of osteoblastextracellular matrix(ECM) and its application in bone tissue engineering. Methods The recentrelated literatures were extensively reviewed. Results The ECM was complex in its components. The configuration of cell and cell’s adhesion, migration, proliferation, and differentiation were subject to the ECM. The bioactivity of the tissue engineering products was revealed by ECM, which predicted the product’s efficiency in clinic application. Conclusion ECM has the potential to become the effective index in evaluating tissue engineered products.
ObjectiveTo review the application and research progress of in vivo bioreactor as vascularization strategies in bone tissue engineering. MethodsThe original articles about in vivo bioreactor that can enhance vascularization of tissue engineered bone were extensively reviewed and analyzed. ResultsThe in vivo bioreactor can be created by periosteum, muscle, muscularis membrane, and fascia flap as well as biomaterials. Using in vivo bioreactor can effectively promote the establishment of a microcirculation in the tissue engineered bones, especially for large bone defects. However, main correlative researches, currently, are focused on animal experiments, more clinical trials will be carried out in the future. ConclusionWith the rapid development of related technologies of bone tissue engineering, the use of in vivo bioreactor will to a large extent solve the bottleneck limitations and has the potential values for clinical application.
To review the structure and function of the calcified cartilage zone and its role in the pathogenesis of osteoarthritis (OA). Methods Recent l iterature about calcified zone was reviewed and analyzed in terms of architecture, composition, biomechanics, and biological function. Results Calcified zone has particular structure and material properties, and functions as a semi permeable membrane; chondrocytes in the calcified zone retain some characteristics of growth plate cells, which play a crucial role in cartilage function maintenance and pathogenesis of OA. Therefore, reconstructionof the calcified zone at osteochondral conjunction has become one of the hot research in the fields of interface tissue engineering. Conclusion It is necessary to pay more attention to calcified cartilage zone, which is important for both the treatment of OA and the preparation of tissue engineered osteochondral composite.
Objective To investigate the effect of collagen type I concentration on the physical and chemical properties of the collagen hydrogel, and to analyze the effect of different concentrations of collagen type I hydrogel on the phenotype and gene expression of the chondrocytes in vitro. Methods Three kinds of collagen hydrogels with concentrations of 12, 8, and 6 mg/ mL (C12, C8, and C6) were prepared, respectively. The micro-structure, compressive modulus, and swelling ratio of the hydrogels were measured and analyzed. The chondrocytes at 2nd passage were cocultured with three kinds of collagen hydrogels in vitro, respectively. After 1-day culture, the samples were stained with fluorescein diacetate (FDA) / propidium iodide (PI) and the cell activity was observed under confocal laser microscope. After 14-day culture, HE staining and toluidine blue staining were carried out to observe the histological morphology, and mRNA expressions of chondrocytes related genes (collagen type II, Aggrecan, collagen type I, collagen type X, Sox9) were determined by real-time fluorescent quantitative PCR. Results With the increase of collagen type I concentration from 6 to 12 mg/mL, the physical and chemical properties of the collagen hydrogels changed significantly: the fiber network became dense; the swelling ratios of C6, C8, and C12 were 0.260 ± 0.055, 0.358 ± 0.072, and 0.539 ± 0.033 at 192 hours, respectively, showing significant differences among 3 groups (P lt; 0.05); and the compression modulus were (4.86 ± 0.96), (7.09 ± 2.33), and (11.08 ± 3.18) kPa, respectively, showing significant differences among 3 groups (P lt; 0.05). After stained with FDA/PI, most cells were stained green, and few were stained red. The histological observation results showed that the chondrocytes in C12 hydrogels aggregated obviously with b heterochromia, chondrocytes in C8 hydrogels aggregated partly with obvious heterochromia, and chondrcytes in C6 hydrogels uniformly distributed with weak heterochromia. Real-time fluorescent quantitative PCR results showed that the mRNA expressions of collagen type II and Aggrecan were at the same level in C12, C8, and C6; the expressions of collagen type I, Sox9, and collagen type X were up-regulated with the increase of collagen type I hydrogels concentration, and the expressions were the highest at 12 mg/mL and were the lowest at 6 mg/mL, showing significant differences among 3 groups (P lt; 0.05). Conclusion Increasing the concentration of collagen hydrogels leads to better mechanical properties and higher shrink-resistance, but it may induce the up-regulation of cartilage fibrosis and hypertrophy related gene expression.
Decellularized extracellular matrix (dECM) has been widely used as a scaffold for regenerative medicine due to its high biomimetic and excellent biocompatibility. As a functional polymer material with high water content and controlled fluidity, hydrogel is very promising for some minimally invasive surgery in clinical practice. In recent years, with the rapid development of hydrogel theory and technology, dECM hydrogel has gradually become a research hotspot in the field of regenerative medicine. In this paper, the related researches in recent years are reviewed regarding the preparation of dECM hydrogel and its preclinical application. The future clinical use is also prospected.
Objective Extracellular matrix is one of the focus researches of the adi pose tissue engineering. To investigate the appropriate method to prepare the porcine skeletal muscle acellular matrix and to evaluate the biocompatibility of the matrix. Methods The fresh skeletal muscle tissues were harvested from healthy adult porcine and were sl iced into2-3 mm thick sheets, which were treated by hypotonic-detergent method to remove the cells from the tissue. The matrix was then examined by histology, immunohistochemistry, and scanning electron microscopy. The toxic effects of the matrix were tested by MTT. Human adi pose-derived stem cells (hADSCs) were isolated from adi pose tissue donated by patients with breast cancer, and identified by morphology, flow cytometry, and differentiation abil ity. Then, hADSCs of passage 3 were seeded into the skeletal muscle acellular matrix, and cultured in the medium. The cellular behavior was assessed by calcein-AM (CA) and propidium iodide (PI) staining at 1st, 3rd, 5th, and 7th days after culturing. Results Histology, immunohistochemistry, and scanning electron microscopy showed that the muscle fibers were removed completely with the basement membrane structure; a large number of collagenous matrix presented as regular network, porous-like structure. The cytotoxicity score of the matrix was grade 1, which meant that the matrix had good cytocompatibil ity. The CA and PI staining showed the seeded hADSCs had the potential of spread and prol iferation on the matrix. Conclusion Porcine skeletal muscle acellular matrix has good biocompatibility and a potential to be used as an ideal biomaterial scaffold for adi pose tissue engineering.
ObjectiveTo summarize the research progress of tissue engineering technology to promote bone tissue revascularization in osteonecrosis of the femoral head (ONFH).MethodsThe relevant domestic and foreign literature in recent years was extensively reviewed. The mechanism of femoral head vascularization and the application progress of tissue engineering technology in the promotion of ONFH bone tissue revascularization were summarized.ResultsRebuilding or improving the blood supply of the femoral head is the key to the treatment of ONFH. Tissue engineering is a hot spot in current research. It mainly focuses on the three elements of seed cells, scaffold materials, and angiogenic growth factors, combined with three-dimensional printing technology and drug delivery systems to promote the revascularization of the femoral bone tissue.ConclusionThe strategy of revascularization of the femoral head can improve the local blood supply and delay or even reverse the progression of ONFH disease.
Objective To review the research progress of articular cartilage scaffold materials and look into the future development prospects. Methods Recent literature about articular cartilage scaffold for tissue engineering was reviewed, and the results from experiments and clinical application about natural and synthetic scaffold materials were analyzed. Results The design of articular cartilage scaffold for tissue engineering is vital to articular cartilage defects repair. The ideal scaffold can promote the progress of the cartilage repair, but the scaffold materials still have their limitations. Conclusion It is necessary to pay more attention to the research of the articular cartilage scaffold, which is significant to the repair of cartilage defects in the future.
Objective To introduce the materials, preparative technique and endothel ial ization modification of scaffold. Methods The recent original articles about vascular tissue engineering were extensively reviewed and analyzed. Results The materials including natural materials, biodegradable polymers and composite materials were studied in the field of scaffold. The ways of casting, cell self-assembly, gel spinning and electrospinning were appl ied to prepare the scaffold of vascular tissue engineering. The modification of scaffold was one of the most important elements for vascular tissue engineering. Conclusion The recent researchs about scaffold of vascular tissue engineering focus on composite material and electrospinning, the modification of scaffold can improve the abil ity of adhesion to endothel ial cells.