OBJECTIVE: To fabricate artificial human skin with the tissue engineering methods. METHODS: The artificial epidermis and dermis were fabricated based on the successful achievements of culturing human keratinocytes(Kc) and fibroblasts (Fb) as well as fabrication of collagen lattice. It included: 1. Culture of epidermal keratinocytes and dermal fibroblasts: Kc isolated from adult foreskin by digestion of trypsin-dispase. Followed by comparison from aspects of proliferation, differentiation of the Kc, overgrowth of Fb and cost-benefits. 2. Fabrication of extracellular matrix sponge: collagen was extracted from skin by limited pepsin digestion, purified with primary and step salt fraction, and identified by SDS-PAGE. The matrix lattice was fabricated by freeze-dryer and cross-linked with glutaraldehyde, in which the collagen appeared white, fibrous, connected and formed pores with average dimension of 180 to 260 microns. 3. Fabrication artificial human skin: The artificial skin was fabricated by plating subcultured Kc and Fb separately into the lattice with certain cell density, cultured for one week or so under culture medium, then changed to air-liquid interface, and cultured for intervals. RESULTS: The artificial skin was composed of dermis and epidermis under light microscope. Epidermis of the skin consisted of Kc at various proliferation and differentiation stages, which proliferated and differentiated into basal cell layer, prickle cell layer, granular layer, and cornified layer. Conifilament not only increased in number, but also gathered into bundles. Keratohyalin granules at different development stages increased and became typical. The kinetic process of biochemistry of the skin was coincide with the changes on morphology. CONCLUSION: Tissue engineered skin equivalent has potential prospects in application of repairing skin defect with advantages of safe, effective and practical alternatives.
Objective To evaluate the effect of composite (bFGF/PDPB) of basic fibroblast growth factor（bFGF） and partially deproteinized bone (PDPB) on the repair of femoral head defect. Methods Forty-eight femoral heads with defect derived from 24 New Zealand rabbits were divided into 3 groups at random, which were implanted with bFGF/PDPB(group A), PDPB(group B) and nothing(group C) respectively.The rabbits were sacrificed at 2,4,and8 weeks after operation, and then the femoral heads were obtained. The specimens injected with Chinese ink were created. Then X-ray examination, histopathological and morphological examination of blood vessel, and image analysis were made. Results The bone defects healed completely 8 weeks after operation in group A. The implants in the repaired tissue were not substituted completely in group B. The bone defects did not heal completely in group C. Two weeks after operation, affluent newly formed vessels were seen in repaired areas in groupA. No significant difference between group A and group B was observed 8 weeks after operation. In group C, newly formed vessels were scarce 2, 4, and 8 weeks after operation. There were 3 sides rated excellent, 2 good and 1 fair in group A; 1 excellent, 2 good, 2 fair and 1 poor in group B; and 1 fair and 5 poor in group C according to the X-ray evaluation 8 weeks after operation. Eight weeks after operation, the volume fraction of bone trabecula in repaired tissue was higher in group A than that in group B (Plt;0.05), and the fraction in group C was thelowest among the 3 groups (Plt;0.05). Conclusion The composite ofbFGF and PDPB can effectively promote the repair of femoral head defect of rabbit.
Objective To summarize and review the heterogeneity of bone marrow derived stem cells (BMDSCs) and its formation mechanism and significance, and to analyze the possible roles and mechanisms in intestinal epithel ial reconstruction. Methods The related l iterature about BMDSCs heterogeneity and its role in intestinal epithel ial repair was reviewed and analyzed. Results The heterogeneity of BMDSCs provided better explanations for its multi-potency. The probable mechanisms of BMDSCs to repair intestinal epithel ium included direct implantation into intestinal epithel ium, fusion between BMDSCs and intestinal stem cells, and promotion of injury microcirculation reconstruction. Conclusion BMDSCs have a bright future in gastrointestinal injury caused by inflammatory bowl disease and regeneration.
In order to explore further the regulatory factors to the potentiality in inducing osteogenesis by fibroblasts, the fibroblasts were isolated, and purified from human skin, and were grown in incubation in the media of EGF, IL-6, TNF-alpha and BMP2 at different concentrations for two weeks, then, the markers for osteogenic features were investigated by biochemistry, histochemistry and electron microscopic observations. It was found that the combined use of TNF-alpha and BMP2 could stimulate fibroblasts to secrete alkaline phosphatase, osteocalcin and collagen, and the morphological changes of the fibroblasts were also very striking. In the extracellular matrix, the collagen fibrils, with or without periodicity, were arranged regularly or randomly oriented, and numerous minute calcium granules were interspersed among them. The fibroblasts were interwoven one on top of another in the form of multilayer structure and on the surface, there were secreting granules and piling up of calcium crystals which coalessed steadily and increased in size in forming bony nodules. It was considered that TNF-alpha and BMP2 were capable of inducing the fibroblasts to form bone.
Objective To investigate the possible mechanism of the fibroblasts inducing the vascularization of dermal substitute. Methods Fibroblasts were seeded on the surface of acellular dermal matrix and cultivated in vitro to construct the living dermal substitute. The release of interleukin 8 (IL 8) and transfonming growth factor β 1(TGF β 1) in culture supernatants were assayed by enzyme linked immunosorbent assay, the mRNA expression of acid fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) were detected by RT-PCR. Then, the living substtute was sutured to fullth ickness excised wound on BALBouml;C m ice, and the fate of fibroblast w as observed by using in situ hybridizat ion. Results Fibroblasts cultured on acellular dermalmat rix p ro liferated and reached a single2layer confluence. Fibroblasts could secret IL 28 (192. 3±15. 9) pgouml;m l and TGF-B1 (1. 105±0. 051) pgouml;m l. There w as the mRNA exparession of aFGF and bFGF. Fibroblasts still survived and proliferated 3 weeks after graft ing. Conclusion Pept ides secreted by fibroblasts and its survival after graft ing may be relat ive to the vascularizat ion of the dermal subst itute.
OBJECTIVE: To investigate the changes of fibroblast growth factor (FGF) in burn wounds. METHODS: The FGF expression in the center of wound granulation, the edge of wound, the healed part of wound, the normal skin of patients, and the heal course of second degree burn wounds were detected by immunohistochemical methods. RESULTS: The expression intensity of FGF was different in the different sites of third degree burn wounds. The highest contents of FGF was in the center granulation of burn wounds, the less was in the borderline of wound and healed skin, and the least was in the healed skin. FGF expression mainly concentrated in the middle layer of wound, and almost no FGF expression in normal skin. The most FGF expression was occurred at 14 days after injury in second degree of burn wound. CONCLUSION: The changes of FGF in wounds are closely related to the wound healing, and rational use of FGF can promote wound healing.
Objective To investigate the influence of lipopolysaccharide(LPS) on the proliferation and collagen synthesis of normal human skin fibroblasts so as to elucidate its relation with skin wound healing. Methods Fibroblasts wereisolated and cultured in vitro, and then exposed to different doses of LPS(0.005, 0.010, 0.050, 0.100, 0.500, and 1.000 μg/ml) from E.coli055∶B5 respectively. Then the absorbance (A) value of fibroblasts was determined with the colorirneteric thiazolylblue (MTT) assay, and the cell number was counted under inverted phase contrast microscope from the 1st day to the 9th day after LPS administration, and collagen synthesis of fibroblasts in culture medium was measured with the method of pepsin digestion after incorporation of 3Hproline into stable, single-layered, confluent fibroblasts at 7 days after LPS administration. Results Compared with control group, A value increased with the increasing concentration of LPS (0.005 μg/ml 0.500 μg/ml) and LPS of 0.100 μg/mlgroup had the best effect. The difference was remarkable from the 5th day to the 9th day(P＜0.05). A value decreased when challenged with the LPS of 1.000 μg/ml and the difference was remarkable from the 3rd day to the 9th day(P＜0.05). Cell number increased with theadministration of LPS of different concentrations (0.005 μg/ml 0.500 μg/ml) and LPS of 0.100 μg/mlgroup had the best effect. The difference was remarkable from the 1st day to the 6th day(P＜0.05). Cell number decreased remarkably when challenged with LPS of 1.000 μg/ml and the difference was remarkable from the 2nd day to the 9th day(P＜0.05). Collagen synthesis increased when challenged with LPS of different concentrations (0.005 μg/ml 0.500 μg/ml) and the 0.100 μg/ml group had the best effect. However, when the dose of LPS reached 1.000 μg/ml, it inhibited collagensynthesis. Conclusion LPS could promote the proliferation andcollagen synthesis of fibroblasts within a certain range of low doses, but over-high dose ofLPS might inhibit the proliferation and collagen synthesis of fibroblasts, suggesting that LPS of certain concentrations might contribute to wound healing, while excessive LPS has negative effect on wound healing.
Objective To investigate the phenotypic change and proliferation of fibroblasts in human inflammatory strictured bile duct wall. Methods We observed the density and ultrastructure of fibroblasts, and the histologic structure in human normal bile duct wall and inflammatory strictured bile duct wall by light and electron microscope.Results The results showed that fibroblasts were the main source of extracellular matrix production in bile duct wall. The phenotype of fibroblasts in inflammatory strictured bile duct wall changed obviously, quiescent fibroblasts were activated and transformed to myofibroblasts, with massive proliferation. Conclusion These data suggest that massive proliferation of activated fibroblasts and myofibroblasts is the main source of extracellular matrix overproduction which results in inflammatory bile duct stricture.
Objective To study the adhesion-preventing effect of basic fibroblast growth factor(bFGF) combined slow-releasing degradable membrane.Methods The bFGF combined slow-releasing degradable membrane was made from bFGF and the reagent which could promote fibrinogen synthesize. Sixty-six SD rats were divided into groups A,B,C randomly (22 rats each group). In group A, sutured achilles tendon were encapsulated with bFGF combined slow-releasing degradable membrane;in group B, sutured achilles tendon were encapsulated with degradable membrane without any drug; in group C, achilles tendon were only sutured. Ninety days later, light-microscope, electronmicroscopoe, figureanalysing, hydroxyproline content, extent of peritendon adhesion and biomechanic test were evaluated.Results ①The amount of fibroblast and fibrinogen inside the sutured tendon in group A was larger than that inits peripheral connective tissue and in groups B and C (P＜0.05). Thecontent of hydroxyproline and the ultimate tensile strength in group A was higher than those in groups B and C(P＜0.01).② The peripheral tissue in group A almostremains the formal loose connective tissue, but it became dense connective tissue in groups B and C and grew into the tendon. Moreover, the extent of adhesion in group A was lesser than that in groups B, C according to the mensuration of peritendon adhesion.Conclusion The bFGF combined slow-releasing degradable membrane can make the intrinsic healing of tendon faster than peripheral