RESUMO
Objective To evaluate the expression of human vascular endothelial cell growth factors 165 (hVEGF165) gene transfected into fibroblasts by recombinant adenovirus and study the repairing effect of this cells on radiated skin ulcer in rats.Methods The recombinant adenovirus with hVEGF165 was established and transfected to rat primary fibroblasts, and its expression of hVEGF165 in fibroblasts was identified with real-time PCR, immunocytochemistry and Western blot.Twenty four clean grade SD rats of were irradiated locally with 50 Gy γ rays to generate an animal model of radiation skin injury.The hVEGF165-transfected cells were injected to the irradiated site under rat skin 7 d post-irradiation.The therapeutic effects on the irradiated skin wound were evaluated through general observation as well as histological staining of HE.The expression of hVEGF in the irradiated skin tissue with fibroblasts injection was analyzed by Real-time PCR.Results The hVEGF165 gene was overexpressed in the transfected cells and approached to 88 373-fold bigger compared to controls transfected with blank vectors, and an extensive expression of VEGF in the cytoplasm of transfected cells was observed by immunohistochemistry.VEGF protein with the relative molecular mass of 23 000 was also detected in cell lysate by Western blot.The local skin ulcers in rats occurred about two weeks after irradiation.In the hVEGF165-transfected group, the average area of radiation-injured skin was 40.2 mm2, about 57％ less than that of the control group transfected with blank vectors so that the healing time was shorten by 6 days.The relative concentration of hVEGF mRNA in the skin tissue of rats injected with hVEGF165-transfected cells were 5.15-fold and 4.15-fold bigger compared to that of controls (t =3.385,3.220, P ＜ 0.05) at 3 and 7 d after administration.Conclusions The primary fibroblasts transfected with hVEGF165 gene could efficiently release VEGF to the irradiated skin tissue and promote the recovery of irradiation skin ulcers by shortening the healing time and thus enhanced the therapeutic effect on skin wounds.
RESUMO
BACKGROUND:It is important to prepare a mal eable putty to repair irregular bone defects because the preformed bone substitute material cannot suit to bone defects. OBJECTIVE:To prepare mal eable demineralized bone matrix/hyaluronic acid putty and to screen out the optimal composite ratio, as wel as to evaluate its cellcompatibility. METHODS:Demineralized bone matrix was prepared from the cortical bone of healthy donors. The hyaluronic acid was dissolved at concentrations of 0.75%, 1.5%, 3%, 4.5%, and the viscosity of them was measured. Then 450 mg demineralized bone matrix was compounded with 1 mL hyaluronic acid solution to prepare the demineralized bone matrix/hyaluronic acid putty, and the optimal ratio of demineralized bone matrix/hyaluronic acid was screened by the disintegrated time of the putty at 37 ℃. L-929 mouse fibroblasts were cultured in the leaching liquor of demineralized bone matrix/hyaluronic acid, and the cytotoxicity was tested by cellcount kit-8 assay at days 1, 4 and 7. RESULTS AND CONCLUSION:With the increase of hyaluronic acid concentration, the viscosity of hyaluronic acid solution was increased;the demineralized bone matrix/hyaluronic acid putty was strengthened and the disintegrated time was prolonged gradual y. When the ratio of demineralized bone matrix/hyaluronic acid was 15/1, demineralized bone matrix/hyaluronic acid was molded easily, and the disintegrated time was 8 hours in 7 ℃ PBS. The results of cytotoxicity showed that cellproliferation rates were 93.72%, 101.65%and 97.68%at days 1, 4 and 7 respectively, while the cytotoxicity was in grade 0 or 1. These findings indicate that demineralized bone matrix/hyaluronic acid putty at a compound ratio of 15:1 can be molded easily and difficult to disintegrate, with low cytotoxicity.
RESUMO
BACKGROUND: Human allogenic acellular dermal matrix, as a kind of permanent dermal scaffold, has widely used in the fields of burn wound reparation and aesthetic medicine. However, it is limited due to insufficient resources. OBJECTIVE: To prepare porcine acellular dermal matrix (PADM) dermal matrix, in addition, to estimate its in vitro biocompatibility. DESIGN, TIME AND SETTING: An in vitro cytology contrast experiment. The Experiment was performed at the laboratory of Biomaterials and Pharmacy Technology Institute, China Institute for Radiation Protection between August 2007 and June 2008. MATERIALS: The experiment pigs were supplied by experimental animal center of China Institute for Radiation Protection. Human fibroblasts were obtained from prepuce tissues of healthy children who underwent circumcision at the Shanxi Provincial General Hospital, Chinese People's Armed Police Forces. METHODS: The PADM was prepared from porcine skin by removing epidermis with a hypertonic salt solution and excluding cellular components in dermis with sodium dodecyl sulfate, and trypsin in hypersonic conditions. Human fibroblasts were cultured in vitro, and the biocompatibility of PADM was estimated with MTT method and contact method. MAIN OUTCOME MEASURES: ①Histological morphology of PADM. ②In vitro biocompatibility of PADM. RESULTS: The prepared PADM was a kind of matrix with normal structure and organization of collagen without epidermis and any cellular components in the dermis. The extraction of the porcine acellular dermal matrix had no effect on proliferation of the cultured human fibroblast. The cultured human fibroblasts could attach and proliferate on PADM. CONCLUSION: The PADM effectively removed epidermis and all cellular components with excellent biocompatibility can be obtained by this preparation method.
RESUMO
BACKGROUND:The need for bone graft and its substitutes has dramatically increased during the past decade. Either bio-derived graft materials or synthetic materials cannot satisfy this need. Study of composite bone graft has become a focused field.OBJECTIVE: To develop a novel porous poly (lactic-acid) (PLA)/bone matrix gelatin (BMG) bioactive composite material by means of supercritical carbon dioxide fluid technique (SC-CO2) and evaluate the bone forming potential in vitro.DESIGN: A comparative study and observation.SETTING: Research Center of Tissue Engineering, Southern Medical University; Institute of Biomaterials and Pharmaceutical Technique, China Institute for Radiation Protection.MATERTALS: Mouse osteoblast-like MC3T3-E1 cells were obtained from RIKEN Cell Bank in Japan. PLA was supplied by the Institute of Bio-technique of Jinan University. Alkaline phosphatase (ALP) kit was the product of Nanjing Jiancheng Bio-engineering Institute. MC3T3-E1 cells were cultured in Dulbecco's modified eagle medium (DMEM) (Gibco Laboratories, USA) supplemented with 10% fetal bovine serum (FBS, Si Ji Qing, China), 100 mg/L penicillin and 100 U/L streptomycin in a 37℃ humidified atmosphere. The cells were passaged with 0.25% trypsin (Gibco Laboratories, USA).METHODS: The experiment was carried out in the Research Center of Tissue Engineering, Southern Medical University from October 2005 to July 2006. The porous PLA/BMG composite biomaterials and PLA were prepared with SC-CO2 technique, and then macroscopic and microscopic observations were performed. The MC3T3-E1 cells were co-cultured with PLA and PLA/BMG in vitro, and DMEM was taken as the blank control group. Each well was pictured with digital camera.The percentage of the stained area, standing for the calcification deposition, was determined with an image processing and analysis software. The ALP activity and calcium content were determined with the method of ultrasonic cell lysis.MArN OUTCOME MEASURES: ① Macroscopic and microscopic observation of PLA/BMG; ③ Quantitative measurement of the calcification area; ② ALP activity and calcium content.RESULTS: ① Macroscopic and microscopic observation of PLA/BMG: The PLA/BMG showed good homological porosity with the size of 50-150 μm and connectivity: There were many holes with the size of 5-10 μm in the PLA/BMG walls. The PLA and BMG were mixed uniformly. ② Calcification areas: The percents of calcification area were significantly different among the PLA/BMG group, PLA group and blank control group [(42.98±4.44)%, (9.55±1.94)%, (0.86±0.41)%, P ＜ 0.01]. ③ Results of calcium content and ALP activity: The ALP activities were significantly different among the PLA/BMG group, PLA group and blank control group [(5 427.58±1173.57), (1 060.54±500.27),(40.01±24.50) nkat/g, P ＜ 0.05-0.01]; The calcium content in the PLA/BMG group was higher than those in the PLA group and blank control group [(3.51±1.64), (1.04±0.21), 0.70±0.24] mmol/g, P ＜ 0.01].CONCLUSTON: The PLA/BMG prepared by means of SC-CO2 has a good osteoinductive activity and it is worth studying further as bone biomaterial and bone tissue engineered scaffold.