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 observe the effects of hyaluronic acid (HA) and basic fibroblast growth factor (bFGF) on the proliferation of the cells from medial collateral ligament (MCL) and anterior cruciate ligament (ACL) cells. METHODS: The MCL cells and ACL cells of mature New Zealand white rabbit were cultured, while HA, bFGF or HA and bFGF were added to the cell culture media, the cellular proliferation was assayed by MTT method. RESULTS: HA only had no effect on the preoliferation of ACL cells, but had a small stimulatory effect on the proliferation of MCL cells. The addition of 1 ng/ml bFGF enhanced the proliferation of both MCL and ACL cells significantly, and this enhancement was maximal in the concentration of 50 ng/ml. However, the enhancement of proliferation of MCL and ACL cells could be achieved when the combination of HA in concentration of 100 micrograms/ml and bFGF in concentration of 100 ng/ml. CONCLUSION: It is evident that bFGF can enhance the proliferation of the ligament cells. HA can maintain the normal growth of ACL cells with no effect on the proliferation of the cells, while HA has a small stimulatory effect on the proliferation of MCL cells. However, when bFGF is coordinated with HA, more improvement of cellular proliferation can be achieved. HA can be used as a potential carrier for bFGF to enhance the healing of ligamentous tissue injuries.
Objective To establish a better method of isolating andculturing ofneural stem cells(NSCs) in neonatal rat brain. Methods Tissue of brain was isolated from neonatal rats. Different medium and culture concentration were used toculture NSCs of neonatal rat. The culture concentration used were 1×10 4, 1×105, 1×106and 1×107/ml respectively. Ingredient of medium was classified into group 1 to 8 respectively according to whether to add 2% B27, epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) as well as the difference in culture concentration. The cells were induced to differentiate asto be confirmed as NSCs, and then were checked by phase contrast microscopy and identified by immunocytochemistry. Results The cells isolated and cultured gathered into neurospheres. The cells were capable of proliferating and maintaining longterm survival in vitro. The cells could be differentiated into neurons and glia.It was to the benefit of the survival of NSCs to add 5% fetal bovine serum(FBS)into the medium at the beginning of the culturing. When 10% FBS was added intothe medium, the neurospheres differentiated quickly. When concentration 1×106/ ml was used, the growth rate of the cells was the highest of all the concentrations. Reasonably higher cell concentration promoted the proliferation of NSCs. It was necessary to add 2% B27, EGF, and bFGF into the medium. The cells had the best growth when 2% B27, 20 ng/ml bFGF and 20 ng/ml EGF were added into the culture medium. EGF and bFGF had cooperative effect. Conclusion A better method of isolating and culturing of NSCs in neonatal rat brain is established and the foundation for future research is laid.
Objective To summarize the research progress of controlled release of angiogenic factors and osteogenic factors in bone tissue engineering. Methods The domestic and abroad literature on the controlled release structure of growth factors during bone regeneration in recent years was extensively reviewed and summarized. Results The sustained-release structure includes direct binding, microsphere-three-dimensional scaffold structure, core-shell structure, layer self-assembly, hydrogel, and gene carrier. A sustained-release system composed of different sustained-release structures combined with different growth factors can promote bone regeneration and angiogenesis. Conclusion Due to its controllability and persistence, the growth factor sustained-release system has become a research hotspot in bone tissue engineering and has broad application prospects.
Objective To investigate the effect and mechanism of growth factors on intestinal compensation after massive intestinal resection， and understand the progress of growth factors in nutrition support treatment for short bowel syndrome （SBS）. Method The related literatures about the application and effect of growth factors in the patients with SBS were reviewed. Results Different kinds of growth factors had different effects on intestinal adaptation after massive intestinal resection. The application of growth factors according to the specific circumstances of the patients with SBS could shorten the residual small intestine compensatory time and improve the nutrition status of the patient with SBS. Conclusions Growth factors play important role in promoting the intestinal adaptation after resection. Different kinds of growth factors have their effects and it’s helpful for getting rid of the total parenteral nutrition early. However， much work still remains to be done.
OBJECTIVE To compare the osteogenesis of recombination artificial bones, which are bovine deproteined bone (bDPB) and bovine bone morphogenetic protein (bBMP), combined with tumor necrosis factor alpha (TNF alpha), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) respectively. METHODS One hundred trephined skull bone defects in fifty rabbits were divided into four groups, which implanted with bDPB/bBMP/TNF alpha, bDPB/bBMP/bFGF, bDPB/bBMP/EGF, and bDPB/bBMP respectively. X-ray and histological changes were observed in the 1st, 2nd, 4th, 6th, 8th weeks after implantation. The content of 35S and 45Ca and ash weight were measured at 10 and 42 days after operation. RESULTS The osteogenesis of bDPB/bBMP/TNF alpha group was ber than that of bDPB/bBMP/bFGF group(P lt; 0.01), while bDPB/bBMP/bFGF group was ber than that of bDPB/bBMP/EGF(P lt; 0.01). No significant statistical difference were found between bDPB/bBMP/EGF and bDPB/bBMP(P gt; 0.05). CONCLUSION TNF alpha combined with bBMP and carrier can stimulate bone formation and increase the volume of new bone in vivo. It suggests that bDPB/bBMP/TNF alpha is a valuable biomaterial of bone graft.
Objective To investigate the effect of acid, basic fibroblast growth factor (aFGF, bFGF) and epidermal growth factor (EGF), andtheir combination on the proliferation of rabbit anterior cruciate ligament (ACL) and medial collateral ligament (MCL) in vitro. Methods Thecells of ACL and MCL were isolated and subcultured from the knee joints of tenweek-old New Zealand white rabbits. The cells were seeded into 96-well corning cluster plates. Three growth factors of different concentration alone or in combination were added into the culture medium respectively, which were 0, 1, 5, 10, 50 and 100 ng/ml for aFGF, bFGF and 0, 1.56, 3.13, 6.25, 12.5, 25 and 50 ng/ml for EGF. The proliferation of the fibroblasts was measured for 48 h with XTT method. Results All of the three growth factors alone promoted the cell proliferation of ACL and MCL fibroblasts. The concentration of aFGF hada significant effect on the proliferation of both ACL and MCL fibroblasts. The concentration of 1 ng/ml bFGF and 5 ng/ml EGF was most effective in promoting the proliferation of ACL, and both bFGF and EGF had a significant effect on MCL. 5ng/ml aFGF with 50 ng/ml EGF had effect on ACL. 1 ng/ml aFGF with 3.13 ng/ml EGF had effect on MCL. Conclusion The three growth factors may promote the cell proliferation of ACL and MCL. These findings suggest that topical application of aFGF, either alone or in combination with EGF may have the potential to promote the proliferation of rabbit ACL and MCL,and aFGF of low concentration in combination with EGF is more effective than single growth factor.
Objective To review recent studies in molecular biology of gastric cancer. Methods Relevant references were reviewed. Results The development and progression of gastric cancer were correlated with oncogenes, growth factors, cyclins, tumor suppressor genes, cell adhesion molecules and unstability of genes.Conclusion Gastric cancer is related to much mutation of genes.
Objective To investigate the effect of machine-enzyme digestion method on the residual quantity of small intestinal submucosa (SIS) cell and the content of growth factors. Methods Fresh jejunum of pig within 4 hours after harvesting was prepared into SIS after machine digestion (removing placenta percreta, mucosa, and muscular layer), degrease,trypsinization, abstergent processing, and freeze drying. Samples were kept after every preparation step serving as groups A, B, C, D, and E, respectively (n=4 per group). And the fresh jejunum served as control group (group F, n=4). The histological alteration in each preparation process was reviewed with HE staining and scanning electron microscope (SEM). Nest-polymerase chain reaction (PCR) was used to determine the content of death associated protein 12 (DAP12), and enzyme-linked immunosorbent assay (ELISA) was appl ied to detect the content of vascular endothel ial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor β (TGF-β), tumor necrosis factor α (TNF-α). Results HE staining and SEM observation showed that there were residual cells in groups A and B, and there were no residual cells in groups C, D, and E. Nest-PCR test revealed the occurrence of DAP12 in each group. The contents of DAP12 in groups A, B, C, D, E, and F were (18.01 ± 9.53), (11.87 ± 2.35), (0.59 ± 0.27), (0.29 ± 0.05), (0.19 ± 0.04), and (183.50 ± 120.13) copy × 106/cm2. The content of DAP12 in group F was significant higher than that of other groups (P lt; 0.05), groups A and B was higher than groups C, D, and E (P lt; 0.05), there were significantdifferences among groups C, D, and E (P lt; 0.05), and there was no significant difference between groups A and B (P gt; 0.05). The ELISA test showed the content of VEGF, bFGF, TGF-β, and TNF-α in group A was significantly higher than that of groups B, C, D, and E (P lt; 0.05), and there was no significant difference among groups B, C, D, and E (P gt; 0.05). Conclusion SIS prepared by simple mechanical method has more residual cells, while the machine-enzyme digestion method can effectively remove the cells and significantly reduce the DAP12 content. This approach can not obviously reduce the growth factor content in SIS.
Objective To study the effect of transforming growth factor β1(TGF-β1) and insulin-like growth factor 1(IGF-1) during the induction course from marrow mesenchymal stem cells (MSCs) to chondrocytes and to observe the effect of cell density on cell induction. Methods Differential time adherent methods were used to purify MSCs obtained from the bone marrow of Kunming mice. MSCs were cultured under special conditionsto induce themto differentiate into chondrocytes. Toluidine blue staining and immunofluoresence were used to identify those induced chondrocytes.TGF-β1 and IGF-1 were used individually or in combination under two different culture patterns: pellet culture and monolayer culture. According to different growth factors, experiment included 3 experimental groups(TGF-β1+IGF-1 group,10 ng/mland 50 ng/ml respectively;TGF-β1 group, 10 ng/ml; and IGF-1 group, 50 ng/ml) and control group(without growth factor). In TGF-β1+IGF-1 group, toluidine blue staining and immunofluoresence staining were carried out at 14 days and 21 days. The effect ofTGF-β1 and IGF-1 on the expression of collagen Ⅱgene was detected by RT-PCR at 7, 14 and 21 days of induction; the expressionsof collagen Ⅱ were compared between two culture patterns. Results In TGF-β1+IGF-1 group, the histological examination and immunofluoresence showed that those inducted chondyocytes could express collagen Ⅱ at 14 days. The gel electrophoresis results showed that the fragment of collagen Ⅱ gene was seen in TGF-β1+IGF-1 group andTGF-β1 group and that no fragment ofcollagen Ⅱ gene was seen in IGF-1 group and control group. The expression of collagen Ⅱ gene was ber in TGF-β1+ IGF-1 group than inTGF-β1 group, showing significant difference(Plt;0.05). Cells expressed more collagen Ⅱ under pellet culture than under monolayer culture. Conclusion IGF-1 could enhance the effect ofTGF-β1 during the induction course from MSCs to chondrocytes. A certain extent of high cell density is more effective for MSCs to differentiate into chondrocytes.