The quantity or function deficiency of blood vessel grafts hinders many diseases from proper treatment,so tissue engineered blood vessels have gained high attentions.As a crucial component of the tissue engineered blood vessels,how the seed cells can obtain the physiological functions as normal endothelial cells and smooth muscle cells has been focused on.Stem cells are multi-potential and are regarded as proper seed cells.However,it is still a question that which stem cells among a variety of stem cells is the most suitable seed cells for tissue engineered blood vessels.In this review,we make a comparison among kinds of stem cells such as haemopoietic stem cells,bone mesenchymal stem cells and adipose-derived stem cells.We also state their characteristics respectively,and intent to acquaint with their function comprehensively.Thus,this review may provide some references for further studies.

Objective To study the effect of dexamethasone to protect flaps from an ischemia-reperfusion injury and elucidate its mechanism of regulating the death course of the neutrophils. Methods The rats were randomly divided into 3 groups.The vein of the rat was clamped for 8 h after the flap had formed. Group A: the normal flap; Group B: the saline control flap; Group C: the treatment flap with dexamethasone. The survival area of the flaps was measured at 7 days; the apoptotic and necrotic neutrophils,tumor necrosis factor α (TNF-α), and interleukin 10 (IL-10) concentrations were measured. Results The flap survival are as in Groups A and C were larger than those in Group B. The apoptotic neutrophils in Group B were fewer than those in Groups A and C on the 1st and 3rd days after operation; however, they were more in number in Group B than in groups A and C on the 6th day. The necrotic cells in Group B were more in number than those in Groups A and C. In Group B, the plasma TNF-α concentration reached the maximum level at 1 h,while the IL-10 level reached the lowest 3 h after the reperfusion. In Group C, the TNF-α concentration was lower than that in Group B and decreased dramatically at 6 h. The IL-10 concentration was the lowest at 1 h, and increased rapidly at 3 h.Thus,ischemia-reperfusion could injure the flaps, probably through the abnormal action of the neutrophils, such as the disordered secretion of the cytokines and abnormal death course of the neutrophils. Conclusion Dexamethasone can protect the flap from an ischemia-reperfusion injury by its regulation for the neutrophil function.

Objective To explore a new method for reconstruction o f full-thickness defect of eyelid. Methods The composed skin flap which was lined the expanded forehead skin flap with oral mucosa were transferr ed to the defect of eyelid and then sutured anatomically to the eyelid skin. Fou r months later, the composed flap was divided to reconstruct upper and lower eye lids and put an artificial eye into it. Results The appearance and function of the eyelid was partly recovered. Conclusion The reconstruction of full-thickness eyelid defect with expanded and prefabricated skin flap with grafted mucosal liner is better and reliable.

Objective To investigate the mechanism and effect of TMP on melanocytes.Methods MTT method, NaOH-assay and Takahashi method were employed to measure the proliferation, melanin synthesis, tyrosinase activity of melanocytes. Results TMP induced a mild effect on melanocytic proliferation ( p

To investigate the effect of bFGF and sucralfate on the improvement of the quality of expanded skin flap, white piglets were employed to establish a continuous tissue expansion model. They were randomly divided into 3 groups: group 1: both bFGF and sucralfate were injected; group 2: both bFGF and normal saline was injected; and group 3(the control group):only normal saline was injected. Three days after completion of the expansion ,normal and expanded skin flaps were created at random to assess flap viability and stretch back .The results showed that the flap survival length in group 1 was significantly larger than that of the control group and normal random flap( P

OBJECTIVETo investigate the effects of Dragon' s blood extract on proliferation and secret extracellular matrix function of fibroblasts in vitro.

METHODSDragon' s blood was extracted by chloroform, acetoacetic ester, alcohol. Human fibroblast were cultured in vitro in media containing gradient dilutions of Dragon' s blood extracts (0.002, 0.02, 0.2, 2, 20 mg/ml) , which was followed by cell proliferation assessed with MTT assay on 0, 12, 24, 36, 48, 60, 72 h. Under the optimal concentration, the cell growth curves were drawn and the flow cytometry (FCM) was used to determine the changes of cell cycle. On 0, 12, 24, 36, 48, 60, 72 h, the concentration of hyaluronic acid in the supernatant of fibroblast culture was measured by radioimmunoassay.

RESULTS0.2-2 mg/ml Dragon' s blood extracts enhanced the proliferation of fibroblasts in a dose-dependent manner. 2 mg/ml was the optimal dilution of Dragon's blood extract, and it increased the ratio of S cells in cell cycle [(25.80 ± 3.10)%] than control group [(7.50 ± 0.70)%, P < 0.01]. From 12 h to 72 h, in 2 mg/ml Dragon's blood group, concentration of Hyaluronic acid secreted by fibroblasts gradually increased, but were less than control (P < 0.01).

CONCLUSIONSDragon's blood acetoacetic ester extract improved the proliferation of cultured human fibroblasts in vitro, might be beneficial to promote wound healing.

Cell Cycle ; Cell Proliferation ; drug effects ; Culture Media ; chemistry ; Dose-Response Relationship, Drug ; Extracellular Matrix ; Fibroblasts ; cytology ; drug effects ; secretion ; Flow Cytometry ; Humans ; Hyaluronic Acid ; analysis ; secretion ; Plant Extracts ; pharmacology ; Resins, Plant ; Time Factors

Objective To understand acute rejection differences between untreated recipients and rapmycin-treated recipients in a rat free flap allotransplantation model. Methods Brown groin free flaps were transplanted to Lewis recipients. In the treated group, recipients were treated with rapamycin at the dose of 4 mg/kg every day from day 0 to day 14 after transplantation. In the untreated group, recipients didn't receive any treatment. Allografts were evaluated clinically and histologically. Results Allografts in the treated group showed epidermolysis as sign of rejection.Rejection sign of untreated grafts was ischemic necrosis of whole skin. In histological evaluation, the treated grafts showed "band-like" lymphocytes infiltration in the upper dermis when rejection occurred, while the untreated grafts showed thrombosis in the subdermal vessels. Conclusion The differences between the two groups implied that embolization may be responsible for the rejection of free flap allotransplantation in rat model.

BACKGROUND:Recent studies have demonstrated that growth factor, as a molecular signal, regulates cellular proliferation, differentiation, immigration and metabolism. Its expression and regulation play an important role in the chronic wound healing.OBJECTrVE: To observe the effect of vascular endothelial growth factor (VEGF) on the expression of VEGF receptor (VEGFR), basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) mRNA in wound tissue, and elucidate the mechanism of VEGF in promoting wound healing.DESrGN: Controlled animal experiment.SETTING: Department of Plastic Surgery, Xijing Hospital, Fourth Military Medical University of Chinese PLA. MATERIALS: Six New Zealand rabbits, aged 48-60 months, were involved in the experiment. Nanosphere-coated recombinant plasmid DNA eukaryotic expression vector pcDNA3.1/myc-hisA-VEGF166 was donated by Master Jia Ning, who was from Department of Plastic Surgery, Xijing Hospital, Fourth Military Medical University of Chinese PLA. METHODS: This experiment was carried out in the laboratory of Department of Plastic Surgery, Xijing Hospital from October 2004 to June 2005. ①VEGF (VEGF165) was taken as target gene to construct eukaryotic expression vector pcDNA3.1/myc-hisA- VEGF165. Nanosphere- VEGF165 complex was used. Three round excisional wounds, 6 mm in diameter, were created over the ventral surface of ears of anesthetized rabbits, and cartilage was exposed. Gelatin sponge thin slice dipping 100 μL nanosphere-VEGF165 complex was spread on unilateral wounds of each rabbit, and aseptic sealing membrane was spread on outer layer, serving as VEGF group; Gelatin sponge thin slice dipping 100 μL nanosphere without plasmid load was spread on contralateral wound, serving as control group; Skin of rabbit ear subterminal to circumcise region served as normal group. ② At postoperative 14 days, reverse transcription-polymerase chain reaction (RT-PCR) was used to observe the changes in the expression of VEGFR, bFGF and PDGF mRNA in wound tissue. ③ At postoperative 14 days, wound was took as center, and square tissue mass with size of 1 cm×1 cm (full-thickness rabbit ear included) was excised and prepared into sample, then which was stained by haematoxylin & eosin (HE). Under the optical microscope, the growth of newly regenerated granulation tissue was observed. MAIN OUTCOME MEASURES: Expression of VEGFR, bFGF and PDGF mRNA in wound tissue. RESULTS: ①HE staining results showed the growth speeds of granulation tissue and epithelium tissue in VEGF group were obviously faster than those in the control group. ②RT-PCR detected a significantly higher expression of VEGFR, bFGF and PDGF mRNA in the wound tissues in VEGF group than that in the control group (P ＜ 0.05) and normal group (P＜ 0.01).CONCLUSION: Exogenous VEGF up-regulates the expression of VEGFR, bFGF and PDGF mRNA in wound tissue. VEGF may act on its receptor and play an important role in promoting wound healing through its interaction with other cytokines.

Objective　To study the role of TNFα in the plasm a and skin and IL-1 in the serum in the formation of secondary thrombosis after skin avulsion. Methods　After avulsive flap at size of 12 cm×4 cm was inflicted on the hind legs of pigs, skin specimens and venous blood sam ples were taken at various time points. The contents of TNFα in plasma and skin were determined with radio-immunoassay, and the activity of serum IL-1 wi th 3［H］-TdR. Results　The TNFα contents in the plasma and skin were increased significantly after avulsion（P<0.01），which were (41 5±24) ng/L and (298±18.5) ng/L respectively on the 3rd day after the injury. T he activity of IL-1 in the serum was increased (P<0.05) and was (2.59± 0.85 ) ng/L on day 3. Conclusion　The changes of TNFα contents and I L-1 activity in blood and skin play important roles in the inducetion and aggra vation of secondary tissue necrosis and early thrombosis after skin avulsion.

Objective To explore the potential applications of a chamber for in vivo tissue engineering,and to establish a novel model for in vivo tissue-engineered cartilage.Methods Auricular chondrocytes were isolated,cultured and identified from the ears cartilages of New Zealand white rab bits; rabbit auricular chondrocytes(RACs) were seeded into the scaffolds:(1) RACs were seeded into collagen gel scaffold; (2) RACs were seeded into PLGA/collagen gel scaffold in vitro,and the compos ites were placed into the chambers and implanted in the donor rabbit.As control groups,the composites were implanted directly subcutaneously in the donor rabbit without using chambers,and the contents were harvested at 8 weeks after implantation.Gross examination,histologic and immunohistochemical staining and RT-PCR test were performed to evaluate the harvested contents.Results Under the same conditions inside the chambers,the contents formed into new cartilage-like tissue by histo logical and immunohistochemical staining and RT-PCR.In contrast,in the control groups without chambers displayed vascular invasion and inflammatory reaction in the subcutaneous layer of skin,which eventually led to fibrous tissue or absorption.Conclusions Cartilage is successfully constructed in an immunocompetent animal model using a bioinert perforated chamber.This method is effective in creating a relatively favorable environment for cartilage regeneration,which may provide a valuable reference for the clinical application of tissue regeneration.