RESUMO
BACKGROUND: Schwann cells are the only glial cells in the peripheral nervous system and play an important role in the regeneration of peripheral nerves, while they have poor proliferation capacity and decreased activity, need allografts, and are difficult to culture in vitro. OBJECTIVE: To analyze the feasibility of repairing neurologic defects with tissue-engineered nerves constructed with Schwann cells derived from bone marrow stromal stem cells. DESIGN, TIME AND SETTING: Randomized controlled observation was conducted at Heilongiiang Institute of Veterinary Pharmaceutics between March 2004 and April 2005.MATERIALS: Twenty-four 8-weck-old female Wistar rats were used to establish animal models with 10 nun defect of sciatic nerve. METHODS: Twenty-four rats were divided into 3 groups by random digits table, tissue-engineered nerve group, polylactic acid robe group and autologons nerve group, with 8 rats in each group. Tissue-engineered nerve group: tissue-engineered nerve Was used to bridge neurologic defect, which was constructed with Schwann cells derived from bone marrow stromal stem cells, natural extracelhilar matrix gel and degradable polylactic acid tube. Polylactic acid robe group: injecting extracellular matrix gel into degradable polylactic acid tube to bridge neurologic defect. Autologous nerve group: 10 mm of nerve was cut and performed end-to-end anastomosis after revolving 180 degrees. MAIN OUTCOME MEASURES: Functional recovery of sciatic nerve was detected with electrophysiological observation of nerve, and histological observation and axon count of the newly generated nerve tissue at 12 weeks after transplantation. RESULTS: After introduction, adult bone marrow stromal stem cells had the morphology and properties of Schwann cells. The regenerated nerve had grown to the distal end passing through the defect at 12 weeks after transplantation. The detection indexes in the tissue-engineered nerve group and autologous nerve group were better than that in the polylactic acid tube group (P < 0.05), there were no significant differences between the tissue-engineered nerve group and autoiogous nerve group (P < 0.05); The degradation and absorption of polylactic acid tube were obvious in the tissue-engineered nerve group and autologous nerve group. CONCLUSION: Human bone marrow stromal stem cells can be induced to differentiate into Schwann cells in vitro, and tissue-engineered nerve constructed with Schwann cells, extracellular matrix and degradable polylactic acid tube can repair peripheral neurologic defect.
RESUMO
[Objective]To determine the biological effects of transfection of adeno-associated rirus(AAV) BMP4/7 on rabbit bone marrow stromal cells (BMSCs).[Method]The mature peptide of BMP4 and BMP7 were gained by One-Step RT-PCR from the human placenta and the BMP4/7 fusion gene was gained through gene recombinant techniques and then transferred to pGEM plasmid. The BMP4/7 fusion genen was cut down from the pGEM-BMP4/7 and the recombination was successfully completed in colibacillus, and recombinant adeno-assosiated was produced in 293 cells. Rabbit BMSCs were transfected with the recombinant adeno-assosiated virus vectors carrying BMP4/7 fusion gene with differen multiplicitv of infection(MOI) values. Cell growth curves were drawn to evaluate the biologic effect of AAV-BMP4/7 on cyto-activity. The transfection efficiency was measured using MTT method. The ossification of cells was evaluated by investigating the shape change of the cell ability of ALP and OC at 7,14 days after transfection. Cells were then transfected with AAV-BMP4/7 and AAV-EGFP,respectively.[Result]1.We successfully constructed the recombinant adeno-assosiated virus with BMP4/7 fusion gene.2.The ttransfection efficiency of AAV-BMP4/7 was roughly 72% without siginifficant biologic effect on cyto-activity.The ossification of cells was significant after transfection with AAV-BMP4/7. The 1?105 vg/cell MOI value of transfection efficiency was stroger than 5~104 vg/cell MOI value (59.3,8%). 3. The concentrations of ALP and OC in AAV-BMP4/7 transfection groups were significantbly higher than in AAV-EGFP groups (tALP=896.88 P
