OBJECTIVE: From the point of view of material science, the methods of tissue repair and defect reconstruct were discussed, including mesenchymal stem cells (MSCs), growth factors, gene therapy and tissue engineered tissue. METHODS: The advances in tissue engineering technologies were introduced based on the recent literature. RESULTS: Tissue engineering should solve the design and preparation of molecular scaffold, tissue vascularization and dynamic culture of cell on the scaffolds in vitro. CONCLUSION: Biomaterials play an important role in the tissue engineering. They can be used as the matrices of MSCs, the delivery carrier of growth factor, the culture scaffold of cell in bioreactors and delivery carrier of gene encoding growth factors.
OBJECTIVE: To build the trestle of tissue engineering for skin with the collagen. METHODS: The collagen was obtained from the baby cattle hide pretreated by Na2S and elastinase and Protease M, then the collagen was dissolved in 0.5 mol/L acetic acid solution. The collagen was treated with Protease N to minimize its immunogenicity. The resulting collagen could be used to build the trestle of tissue engineering for skin because of good biocompatibility. The collagen molecular weight and structure were analyzed by SDS-PAGE. The bioactivity of trestle was tested in the experiment of the mice wound healing and the cell implantation. RESULTS: The SDS-PAGE result of the collagen treated by Protease M showed the typical spectrum of type I collagen. The built trestle was a collagen sponge matrix in which micropore size was 50-200 microns. It could accelerate wound healing and the implanted fibroblasts could proliferate well. CONCLUSION: The collagen treated by Protease N can get good biocompatibilily and is suitable for building the trestles of tissue engineering for skin with good bioactivity.
OBJECTIVE: To analysis the proliferation properties and telomerase activity of human embryonic tendon cells transformed by ptsA58H plasmid cultured in vitro continuously. METHODS: The 40th, 70th, and 75th passages of transformed human embryonic tendon cells (THETC) were adopted. The collagen secretion of THETC was detected by immunohistochemical methods, the growth curve of different passages of THETC was compared, and chromosome karyotype was analyzed. Total RNA of THETC were extracted to detect human telomerase reverse transcriptase (hTERT) mRNA expression by RT-PCR technique. RESULTS: When THETC were subcultured to 70 passages, the morphological characteristics of cells changed and began replicative senescence. THETC still could secret type I collagen normally. The chromosome of THETC was heteroploid (2n = 94). There were no hTERT mRNA expression. CONCLUSION: SV40 transfection can not make human embryonic tendon cells immortalization, on the other hand, human embryonic tendon cells transformed by ptsA58H plasmid has no tendency of malignant transformation.
OBJECTIVE: To investigate the influence of basic fibroblast growth factor (bFGF) on adhesion characteristics of osteoblasts, aimed at the important problem in bone tissue engineering of how to promote the adherence of osteoblasts to extracellular matrix materials. METHODS: 5 ng/ml, 10 ng/ml, 50 ng/ml, 100 ng/ml, 200 ng/ml bFGF were used to induce bone marrow stromal-derived osteoblasts of rabbit for 24 hours before incubation, and the common culture medium as the control. The attached cells were calculated with stereology method at 0.5 hour, 1st hour, 2nd hour, 4th hour, 8th hour after seeding. RESULTS: The number of attached cells was significant higher in the experimental group when induced by 10 ng/ml bFGF than that in the control group (P lt; 0.01); the number did not increase with the increase of bFGF concentration and there was no significant difference between the experimental group induced by 100 ng/ml bFGF and control group, and the number was even obviously lower in the experimental group when induced by 200 ng/ml than the control group (P lt; 0.01). CONCLUSION: bFGF can influence the adhesion characteristics of osteoblasts, 10 ng/ml bFGF can promote the adherence of osteoblasts to matrix materials, but 200 ng/ml bFGF may inhibit cell adhesion.
OBJECTIVE To investigate the adhesive interactions of cells with materials and the effects of material properties on cell adhesion in tissue engineering. METHODS By looking up the recent literatures dealt with adhesive interactions of cells with materials and reviewing previous work on the adhesion of tissue-derived cells to materials. RESULTS The adhesion characteristics of cells to materials not only depend on the nature of materials, including bulk and surface properties, surface modification, surface morphology, net charge, porosity and degradation rate, but also on the expression of cell surface molecules and their interaction with the material. CONCLUSION The quantitative measure and biophysical mechanisms of cell adhesion to materials might be very important in tissue engineering.
OBJECTIVE: To study the feasibility of calcium polyphosphate fiber (CPPF) as the scaffold material of tendon tissue engineering. METHODS: CPPF (15 microns in diameter) were woven to form pigtail of 3 mm x 2 mm transverse area; and the tensile strength, porous ratio and permeability ratio were evaluated in vitro. Tendon cells (5 x 10(4)/ml) derived from phalangeal flexor tendon of SD rats were co-culture with CPPF scaffold or CPPF scaffold resurfaced with collagen type-I within 1 week. The co-cultured specimens were examined under optical and electric scanning microscope. RESULTS: The tensile strength of CPPF scaffolds was (122.80 +/- 17.34) N; permeability ratio was 61.56% +/- 14.57%; and porous ratio was 50.29% +/- 8.16%. CPPF had no obvious adhesive interaction with tendon cells, while CPPF of surface modified with collagen type-I showed good adhesive interaction with tendon cells. CONCLUSION: The above results show that CPPF has some good physical characteristics as scaffold of tendon tissue engineering, but its surface should be modified with organic substance or even bioactive factors.
Objective To observe the biological characters of chondrocytes in articular loose body and to find out seeding cells for cartilage tissue engineering. Methods Samples from 5 loose body cartilages, 2 normal articular cartilages and 6 osteoarthritis articular cartilages were collected. Part of each sample’s cartilage was histologically studied to observe the chondrocytes distribution the morphologic changes by toluidine-blue staining, chondrocytes’ apoptosis by terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate-biotin nick end-labeling (TUNEL). The rest of each cartilage was digested and isolated by 0.25% trypsin and 0.2% collagenase Ⅱ, and then were cultivated in 10%DMEM. Their morphologic changes were observed 24h later.Comparison was made btween three cartilages. Results Compared with normal cartilage and osteoarthritis articular cartilage, the cells density was higher, their lacunars were larger, cells distribution was irregular, and apoptosis was more apparent in loose body cartilage. Conclusion The characters of chondrocytes from loose body is more like fibroblasts so they can not serve as seeding cells directly for cartilage tissue engineering.
OBJECTIVE: To evaluate the cellular compatibility of three natural xenogeneic bone derived biomaterials. METHODS: Three types of natural xenogeneic bone derived biomaterials were made with physical and chemical treatment, composite fully deproteinized bone(CFDB), partially deproteinized bone(PDPB) and partially decalcified bone(PDCB). Three types biomaterials were cocultured with human embryonic periosteal osteoblasts. The cell growth, attachment, cell cycle, alkaline phosphatase activity were detected to evaluate the cellular compatibility to biomaterials. RESULTS: Osteoblasts attached on all three biomaterials and grew well, the effect of three biomaterials on cell proliferation was PDCB gt; PDPB gt; CFDB. The cell cycle was not obviously affected by three biomaterials. The effect of three biomaterials on alkaline phosphatase activity of osteoblasts was PDCB gt; PDPB gt; CFDB. CONCLUSION: CFDB,PDPB,PDCB have good cellular compatibility without cytotoxic and tumorigenicity, CFDB is the best. The three biomaterials can be used as scaffold materials of bone tissue engineering.
Objective To develop a new method for a tissue engineered vascular graft by combining endothelial cells and an acelluarized allogenic matrix. Methods Acellularized matrix tubes were obtained by a 0.1% trypsin and 0 02% EDTA solution for 24 hours and 1% Triton X 100 for 176 hours, respectively. Endothelial cells were isolated from alloaorta and expanded in vitro. Finally, the inner surface of acellularized matrix was reseeded with endothelial cells. Acellularity and reseeding were analysed by light microscopy and scanning electron microscopy. Results The acellularization procedure resulted in an almost complete removal of the original cells and the loose three-dimensional (3D) matrix. The acellular matrix could be reseeded with expanded endothelial cells in vitro, and endothelial cells had the potential of spread and proliferation. Conclusion Acellular matrix produces by Tritoon X-100 and trypsin possesses satisfactory biocompatibility for allogenic endothelial cell. Vascular grafts can be generated in vitro by a combination of endothelial cells and allogenic acelluarized matrix.
Objective To sum up the research advances of the seed cell and the culture system using in tissue engineering cartilage. Methods The recent original articles about the seed cell and the culture system in tissue engineering cartilage were extensively reviewed. Results At present, autologous or homologous cells is still major seed cell and the three dimensional culture system is also major system for tissue engineering cartilage. Conclusion The source of seed cell for tissue engineering cartilage. Conclusion The source of seed cell for tissue engineering cartilage should be further explored, and the culture system need to be improved and developed.