[Objective] To develop biomimicking chitosan scaffolds with longitudinally oriented micro-channels,and investigate their efficacy in bridging 15 mm sciatic nerve gap in rats.[Methods]Chitosan scaffolds with longitudinally oriented micro-channels were fabricated using unidirectional freezing-dry methods.The chitosan scaffolds were used to bridge 15 mm nerve defect in rats,and their efficacy in bridging nerve gap was evaluated by morphometric analysis,retrograde labeling,electrophysiological studies and behavioral analysis.[Results]The chitosan scaffolds developed in the present study showed longitudinally oriented micro-channels,which resembled the dimensions of basal lamina channels in normal nerves.Implantation of chitosan scaffold achieved axonal regeneration and functional recovery similar to autograft implantation in vivo.[Conclusion]The chitosan scaffolds have inner microstructures which resemble the basal lamina channels in normal nerves.The chitosan scaffold may be used as an alternative to autograft in bridging nerve gaps.

[Objective]AIM To explore the differentiation of neural stem cells from rat embryonic spinalcord in the serum free condition culture medium of OECs.[Method]OECs were acquired by dissection ofolfactory nerve ensheathing and cultured for 20 hours,then suspending cells were put intoselective culture medium and cultured in the fibernectin coated plate.The activity of OECs was detected by MTT method on different periods and the best situation was selected out and serum-free cultured.Exudates of OECs was added into neural stem cells of the third generation.The differentiation of neural stem cells were observed under inverted microscope.The neural stemcells cultured were identified by immumofluorescence method.[Result]The activity of OECs was high on the 9~(th) day and the 12~(th) day.The serum free condition culture medium of OECs induced 53% neuralstem cells to differentiate into neuron-like cells and 42% neural stem cells into astrocytes cells.[Conclusion]The activity of OECs on different periods is different.The serum free condition culture medium of OECs can obviously induced neural stem cells to differentiate into mature neuronecells.

[Objective]To study therapeutic effect of different medicines on motorneuron of spinal cord after explosive injury of spinal cord.[Method]Thirty-six rabbits were randomly divided into model group(group A,n= 12),the dexamethasone experiment group(group B,n= 12) and the methylprednisolone experiment group(group C,n=12),all rabbits were made explosive wound by 0.9 g cyclotrimethylene trinitramine,group A injection NS after blast, group B injection dexamethasone and group C injection methylprednisolone,6 and 24 hours after specimen had been taken out,then morphological change and quantity of the spinal motorneurons be observed under light microscopes.[Result]The reversible change of the neurons of rabbits happened after six hours,after 24 hours,the died motoneuron increase obviously, some rabbits remedied with dexamethasone and methylprednisolone after explosive injury in group B and C,quantity of the died motorneuron marked significant difference than that in the control group(P0.05).[Conclusion]Glycocotical stdroid can protect spinal cord motoneurons after explosive injury of spinal cord.In the experiment,there is no preponderance in early treatment of explosive injury of spinal cord between methylprednisolone and dexamethasone.

[Objective]To explore the differentiation of bone marrow stromal cells(BMSCs) induced by OECs conditioned medium.[Method]The purified OECs were acquired by seleclive culture medium and cultivated in the polylysine coated plate.After 9～12 days culture, OECs conditioned medium was obtained by 2000 r/min configuration and then co-cultivated with purified BMSCs which were 3th generation.The differentiation of BMSCs were observed under inverted microscope and were identified by immumofluorescence method.[Result]The OECs conditioned medium had obviously effects on BMSCs' differentiation.BMSCs differentiation into neuron-like cells ratio was 55% and differentiation into astroctes cells ratio was 23%.[Conclusion]The conditioned medium which comes from OECs culture supernatant has obviously effects on BMSCs' differentiation into neuron-like cells.

[Objective] To develop a new type nerve tissue engineering scaffolds to repair the defect of peripheral nerve and observe the growth of bone marrow stromal cells cultured in vitro on the scaffolds.[Method]The biomaterial was made of I-collagen and gelatin by freeze-drying method,the alignment regularities of microscopic channels and there course directions were observed under the scanning electronic microscope.The size of the micropores and the factor of porosity were also measured.The bone marrow stromal cells were seeded on the collagen scaffolds and cultured for 5 days,then the growth of bone marrow stromal cells cultured in the scaffolds was observed.[Result]All the scaffolds were circular cylinder,the microscopic channels were arranged in parallel manners,and the pore sizes of the channels were uniform.The bone marrow stromal cells were seeded in the scaffolds successfully.[Conclusion]The developed nerve tissue engineering scaffolds have good structure and biocompatibility,which can be used in the repair of the nerve injuries.

[Objective]To introduce a method to obtain Schwann cells from newly born SD rats massively and purely by immunomagnetic heads method.[Method]SD rats that had been born within 5 to 7 days were used. Their bilateral sciatic nerves were dissected under sterile condition. Under 16?microscope the nerve fascicles and the epineurium were carefully extracted in oder to get the nerve tract without impurity cell. Then the nerve tract was cut into small particle about 1 mm3.Two enzymes (0.25% trypsinase and 0.2% collagenaseⅠ)were used to digest the particle of sciatic nerve specimens twice. After using 20% fetal bovine serum to stop the process of digestion,centrifugate(1000r/min,5 min) and DF12 culture medium was added into the precipitation.Seven days later,Schwann cells were purified with immunomagnetic heads.During the whole process,the change of Schwann cells was observed under the inverted biological microscop and vital force of Schwann cells was evaluated.The growth curve of Schwann cell was drawn with MTT.The Schwann cells was identicated under immunofluorescent test and record the purity.[Result]The cell separated from the SD rat's sciatic nerve and cultured in incubator was affirmed as Schwann cells.Immunomagnetic heads can be used to purify the Schwann cells.The 96% vigor and 98% pure Schwann cell cultures were generated and passaged after two days.[Conclusion]This method can obtain massive purified normal schwann cells to satisfy the need of tissue-engineered bioartificial nerve graft.

[Objective]To develop an ideal method for extracting type I collagen from cortical bone and to prepare a collagen-gelatin scaffold.[Method]The cortical bone was disintegrated into bone matrix powder in a high speed mill and was subsequently dehydrated in alcohol,decalcificated in hydrochloric acid and defatted in chloroform:methanol(1:1,v/v).The osscins were extracted using improved pepsin digestion method after the bone matrix powder was dissolved,centrifuged,dialyzed and lyophilized.Type I collagen was then characterized by SDS-PAGE and amino-acid composition analysis.The biomaterial was made of type I collagen and gelatin using freeze-drying method,and the alignment regularities of microscopic channels and their course directions were observed under the scanning electronic microscope.The size of the micropores and the factor of porosity were also measured.[Result] The collagen extracted was confirmed to be type I collagen by SDS-PAGE and amino-acid composition analysis.All the scaffolds looked like circular cylinder,the microscopic channels were arranged in parallel manners,and the pore sizes of the channels were uniform.[Conclusion]Ossein extracted from cortical bone is a real type I collagen that can be applied in the construction of collagen products.

[Objective] To investigate the combined effects of different neurotrophin couples of NGF,bFGF,BDNF on rat spinal cord neurons.[Method]Spinal cord neurons were obtained from SD rats born within 1d,and then were seeded in culture plates.Different factors and their couples were added in each chamber while DMEM/F12 served as controls,concentration of NGF,bFGF or BDNF were 50ng/ml.Phase contrast microscope observation was done.At the 3rd and 7th day after incubation,the cells were detected by ?-tubulin3 immunofluorescence and Hoechst staining.The length of neuritis was measured,and the numbers of neuron cells and nuclears were determined.At the 1st,3rd,5th,7th and 9th day MTT method was used,and the growth curve was made according to OD results.[Result] The length of axon and positive rate in the experimental groups were superior to those in the control group(P

[Objective]To evaluate the posterior approach treatment of old traumatic lumbar spinal stenosis,lumbar kyphosis,intervertebral space stenosis using vertebral plate decompression,nucleus pulposus removal,intervertebral fusion and CAPSTONE cage insertion and internal fixation with pedicle screw and rod,TLIF.[Method]Twenty patients with low lumbar spinal canal and intervertebral space stenosis,lumbar kyphosis caused by trauma were enrolled in this study.There were 13 males and 7 females,with an average age of 31.4 years (range 22-49).Four had lesions of L3、4,10 of L4、5 and 6 of L5S1.One patient was treated at 4 years after injury,3 within 9-15 months,6 within 3-6 months and 10 within 1-3 months after injury.All patients were treated with vertebral plate decompression,some serious patients underwent laminectomy decompression,nucleus pulposus removal,intervertebral fusion,CAPSTONE cage insertion and internal fixation with pedicle screw and rod,TLIF.One week after surgery,patients could wear thoracic waist-iliac orthosis and take out-of-bed activity.[Result]All the patients lumbodynia,lower limb pain,muscle strength and hypoesthesia improved within one week after operation.X-rays showed that both the intervertebral space and the physiological curvature improved to some degrees.Twenty patients were followed up(ranged,1 to 3 years)and the clinical outcomes were good.The average Franke1 grade was 1.4.Re-X-rays showed that interbody fusion was achieved in all 20 patients.No loss was found about the altitude of the intervertebral space and the physiological curvature.[Conclusion]For patients with old traumatic lumbar spinal stenosis,the recovery of body altitude is almost impossible.This method is simple and has less complications.It can be widely used in the clinical practice.

0.05).[Conclusion]There are the same correct effectiveness and the biomechanical stability in the treatment with the slidable pedicle screw system and universal pedicle screw system,meanwhile there is no effect in the adolescent growth.