OBJECTIVE: To explore the relationship between characteristics of transformed cell and tumorigenicity. METHODS: Documents about transformed cell and tumorigenicity were reviewed in detail. RESULTS: Normal biological characteristics and cell function could be maintained in non-tumorigenic transformed cell, but it was changed markedly in malignant transformed cell. CONCLUSION: Non-tumorigenic transformed cell can be served as a standard cell line to study the function and growth characteristics of normal cell.
OBJECTIVE: To investigate the biological characteristics of human muscle satellite cell cultured in vitro. METHODS: Human muscle satellite cells were obtained from skeletal muscle biopsies of six patients during corrective orthopedic surgery, cultivated in growth medium for ten days, then in differentiation medium for additional five days. Human satellite cells were identified with monoclonal antibody against desmin. Cells were observed under phase contrast microscopy. RESULTS: Human muscle satellite cells proliferated in growth medium, and fused to form myotubes in differentiation medium. After 24 hours in differentiation medium, the confluent satellite cells began to fuse actively and achieved the top level at 72 hours. CONCLUSION: Human muscle satellite cell can proliferate and differentiate in appropriate culture condition. Immunocytochemical detection of desmin is the effective early method to determine satellite cell.
OBJECTIVE To investigate the methods to fabricate repair materials of tissue engineered peripheral nerve with bioactivity of Schwann cells (SC). METHODS 1. The materials were made by dry-wet spinning process to fabricate PLA hollow fiber canal with external diameter of 2.3 mm, internal diameter of 1.9 mm, thickness of 0.4 mm, pore size of 20 to 40 microns, pore ratio of 70% and non-spinning fiber net with pore size of 100 to 200 microns, pore ratio of 85%. 2. SC were implanted into excellular matrix (ECM) gel to observe the growth of SC. 3. SC/ECM complex were implanted into non-spinning PLA fiber net to observe the growth of SC. 4. SC, SC/ECM and SC/ECM/PLA were implanted into PLA hollow fiber canal to bridge 10 mm defect of rat sciatic nerve. RESULTS 1. SC were recovered bipolar shape at 1 day after implantation, and could be survived 14 days in ECM gel. 2. After SC/ECM complex was implanted into PLA net, most of SC were retained in the pore of PLA net with the formation of ECM gel. SC could be adhered and grown on PLA fiber. 3. Most of SC in ECM gel could be survived to 21 days after transplantation. Survival cell numbers of SC/ECM and SC/ECM/PLA groups were obviously higher than SC suspension group. CONCLUSION Non-spinning PLA porous biodegradable materials with ECM is benefit for SC to be adhered and grown.
Objective To review researches on bone defect repaired by different kinds of bio-derived bone. Methods The recent relevant literatures were extensively investigated. Preparation of bio-derived bone and effect of bone defect repair were reviewed.Results Theallogeneic and xenogeneic bone treated by different physicochemical method werenot only the substitution for bone but also the scaffold material co-cultured with seed cells to reconstruct tissue engineered bone. Conclusion The tissue engineered bioderived bone is a breakthrough for treatment of bone defect.
OBJECTIVE: To investigate the effects of three-dimentional culture in bioderived material modified by Pluronic F-127 on the growth and function of rabbit periosteal osteoblast in vitro. METHODS: Bio-derived materials were from fresh pig ribs and were modified by Pluronic F-127. Then rabbit periosteal osteoblasts were cultured in bio-derived materials(group A), in the modified bio-derived materials(group B) and on the plastic surfaces as a control (group C), respectively. During a 7-day period, the status of growth, cell viability and alkaline phosphatase(ALP) activity were measured. RESULTS: Osteoblasts attached, elongated and grew well on the modified bio-derived materials. There were no significant difference in osteogenesis and ALP activity between group A and group B(P gt; 0.05). The osteogenesis and ALP activity in groups A, B were less than those in group C (P lt; 0.01). CONCLUSION: Pluronic F-127 can be used for a carrier for bioactive factors to modify bio-derived material.
OBJECTIVE: To prevent the senescence of ’seed cells’ for tissue engineering, the life span of human fibroblasts is extended by reconstitution of telomerase activity, and the osteogenic potential of these fibroblasts are tested. METHODS: The pGRN145 plasmids encoding human telomerase reverse transcriptase (hTERT) were introduced into the normal human primary fibroblasts by electroporation. Telomerase activity was analyzed by TRAP-PCR assay. The beta-galactosidase stain was used to indicate the signs of cell senescence. The hTERT positive fibroblasts were then induced to form bone nodules. The bone nodules were stained by tetracycline and Alizarin Red S. RESULTS: Stable telomerase activity could be detected in the transfected fibroblasts and no signs of cell senescence were found in the fibroblasts cultured for more than 50 doublings. The hTERT positive fibroblasts could form bone nodules when they were cultured in vitro induced by bone morphogentic protein 2 and tumor necrosis factor-alpha. CONCLUSION: The fibroblasts with reconstituted telomerase activity reserve their osteogenic potential.
Objective To const ruct art ificial derm is on co llagen2chondront in sulfate (CS) scaffo ld. Methods Co llagen w as compounded from CS and 1-ethyl-3-(13-dimethyl am inop ropyl) carbodiim ide (EDC) used as a cro sslinker. Physical and chem ical p ropert ies of the scaffo ld w ere characterized by elect ron spect ro scopy fo r chem ical analysis (ESCA ) , scanning elect ron m icrograph (SEM ) , HE staining, and mechanical p roperty test. Derm is fibroblasts w ere iso lated from human embryo and w ere cultured on the scaffo lds. Th rough h isto logical test ing, immunoh istochem ical test ing and biochem ical p roperty test ing, the p roperty of co llagen-CS art ificial derm is w as compared w ith that of colla gen spongy art ificial derm is. Results Co llagen-CS had th ree2dimension st ructure w ith po rous. Compared w ith co llagen scaffo ld, themechanical p roperty of co llagen2CS scaffo ld imp roved. There w eremo re po lar group s on the surface of co llagen-CS scaffo ld. The fibroblasts on the co llagen-CS scaffo ld grew w ell, and art ificial derm is w as const ructed. Conclus ion Co llagen-CS art ificial derm is has mo re excellent bio logical and mechanical p ropert ies. F ibroblasts at tach and p ro liferate bet ter on co llagen2CS scaffo ld than on co llagen scaffo lds.
Objective To comment on the recent advances of production and application of the bio-derived scaffold in the tissue engineered peripheral nerve. Methods The recent articles were systematically analyzed, and then the production methods of the bio-derived scaffold and its application to the tissue engineered peripheral nerve were evaluated and prospected. Results B iological tissues were processed by some methods to produce the bio-derived materials. These mat erials could maintain the structure and components of the tissues. Moreover, the immunogenicity of these materials was reduced. Conclusion Application of the bio-derived materials is a trend in the fabricating scaffold of the tissue en gineered peripheral nerve.
Objective To observe the main biological characteristics and chondrogenesis potency of bone marrow -derived stromal cells(MSCs) after cytokinesinduction or gene modification in vitro. Methods MSCs from an adult New Zealand white rabbit were isolated and cultivated, and then MSCs were divided into the common medium group(Group A, 15%FBS in DMEM), the induced group by cytokines (Group B), the transfected group(Group C)with adenovirus-hepatocyte growth factor transgene (adHGF). The medium of group B consisted of transforming growth factor-β1(TGF-β1,10 ng/ml), basic fibroblast growth factor(bFGF,25 ng/ml) addexamethasone (DEX,10-7mol/L) with 15%FBS in DMEM. Cartilage slices wereobtained from femoral condyles and patellar grove in the same rabbit. The minced cartilage was digested in Ⅱ collagenase (3 mg/ml) to obtain chondrocytes(Group D). The change of cell appearance, proliferation capacity, glycosaminoglycans(GAG), immunohistochemical staining for type Ⅰ, Ⅱ collagen were observed during the 5th passage MSCs and MSCs after induction or gene modification. Expression of mRNA for type Ⅰ and Ⅱ collagen was detected by RT-PCR. Results Primary MSCs proliferated as shortspindle shape, while the 5th MSCs showed longspindle shape. Positive stain of type Ⅰ collagen could be found in groups A, B and C, while positivestain of type Ⅱ collagen was shown in groups B and D. The content of GAG in group B was higher than that in group A, but there was no significant difference between them（Pgt;0.05）, and there was significant difference between groups A and D（Plt;0.05）. No significant difference was noted in groups A,B and C on proliferation by MTT（Pgt;0.05）,except that of at the fourth day after transfection between groups A and C（Plt;0.05）. RT-PCR demonstrated that MSCs always had higher levelsof mRNA type Ⅰ collagen in groups A, B and C. The expression of mRNA type Ⅱ collagen was identified in groups B and D, and only low levels of mRNA type Ⅱ collagen in group C. Conclusion The above results indicate MSCs have a natural tendency of osteogenic differentiation in vitro culture, and also demonstrate the chondrogenic potency with the technique of cytokines induction or gene modification after passage. MSCs can be transfected efficiently being seed cells in tissue engineered bone or cartilage to accept target genes such as adHGF, and have a higher levels of expression in vitro, which lasted 4 weeks at least.
OBJECTIVE: To construct a tissue engineering skin containing melanocytes by employing tissue engineering method. METHODS: The keratinocytes, dermal fibroblasts and melanocytes were isolated and purified. Then the cells were used to construct a tissue engineering skin containing melanocytes. The location of melanocytes in the tissue engineering skin were detected by Dopa staining, transmission electron microscope (TEM) and S-100 immunohistochemical staining. RESULTS: Melanocytes can be detected in the basal layer of the constructed tissue engineering skin. The results of TEM showed that the melanocytes were in good conditions. CONCLUSION: The artificial skin containing melanocytes was successfully constructed in vitro and can be used to repair the full-thickness skin defects.