[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 To induce directional differentiation from spinal cord-derived neural stem cells(SNSCs)into neurocytes in the simulated microenvironment of development of embryonic spinal cord of rat after isolation and culture of SNSCs and to investigate the proliferation and differentiation of SNSCs in vitro.Methods SNSCs were isolated mechanically from rat embryonic(E10 to 11d)spinal cord under microscope.SNSCs were cultured and maintained in serum-free medium.Directional differentiation from SNSCs to neurocytes was induced by adding N4 supplement.The morphologic features of the differentiated cells were noted.Cultured and differentiated cells were identified by immunochemistry stain and t he mean differentiating percentages of the positive cells were calculated.Resul ts SNSCs isolated by the mechanical method under microscope were vigorous and pr oliferative,and could differentiate into neurons,astrocytes and oligodendrocyt es.Conclusion The mechanical method under microscope of isolating SNSCs is simp le and efficient to obtain a high percentage of neurons.N4 supplement can induc e SNSCs to differentiate into neurocytes.

[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 evaluate the effect of selective kyphoplasty in treatment of osteoporotic thoracolumbar multi-vertebral compressive fractures based on preoperative magnetic resonance imaging(MRI).[Method]Twenty-one cases(fifty-seven vertebral bodies) of osteoporotic thoracolumbar multi-vertebral compressive fractures were treated from June 2003 to December 2006.The signal changes in different sequences were confirmed by preoperative MRI.Based on the MRI signal changes,57 vertebral bodies were treated by selective kyphoplasty.Normal balloon pressure and cement volume were performed for the painful vertebral bodies and lower pressure and cement volume were preferred for the vertebral bodies with old fracture.[Result]All patients tolerated the operation well with immediate relief of their back pain in 24 hours.The mean height of the anterior,media and posterior vertebral bodies were(1.7?0.9)cm,(1.7?0.7)cm,(2.5?0.9)cm preoperatively and(2.2?0.4)cm,(2.4?0.6)cm,(2.6?0.3)cm postoperatively.The mean kyphosis was improved from(33.7?10.9) degrees to(25.9?9.3) degrees(P

[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.

[Objective]To initially approach the role of lumbar facet joint derived inflammatory factors in degenerative lumbar spinal canal stenosis. [Methods]Totally 75 cases of degenerative lumbar spinal canal stenosis(LSCS)(n=41)and lumbar intervertebral disc herniation(LDH)(n=34) undergoing posterior lumbar spinal surgery in our department were evaluated in terms of the extent of degenerative arthrosis according to the Weishaup grading criteria.The grading of backleg pain,melosalgia and functional impairment were recorded.The excised lumbar facet joints were collected as species.The content of interleukin-1? and tumor necrosis factor-? in the species were determined by ELISA.[Results]There was no TNF-? detected in both of the two groups.More IL-1? was detected in degenerative lumbar spinal canal stenosis group than that in lumbar intervertebral disc herniation group.It was demonstrated that the content of IL-1? in the species increased as the degeneration of lumbar facet joint sharpened.IL-1?-positive cases in degenerative lumbar spinal canal stenosis group showed higher grading of backleg pain,melosalgia and functional impairment.[Conclusion]The cartilage of degenerative lumbar spinal canal produced more IL-1?.Lumbar facet joint derived inflammatory factors might be one of the reasons that cause backleg pain and melosalgia and functional impairment in degenerative lumbar spinal canal stenosis patients.