Schwann cells proliferate and the axis cylinder regenerates after the injury of the peripheral nerves. Schwann cells are a vital factor in the process of regeneration of injured nerves. The article summarizes the survival and apoptosis adaptation of Schwann cells after the injury of the peripheral nerves. It discusses massive NGF secreting, P75 expressing, and IGF 2, PDGF BB, NT 3 and CNTF secreting. It also supposes that there might be a homeostasis between survival and apoptosis in the proliferated Schwann cells and brings forward the question regarding reassessment of administration of NGF to enhance regeneration of the injured peripheral nerves.

Objective To study the morphological changes of the Schwann cells within the predegenerated nerve. Methods The ulanr and the median nerves were cut bilaterally at the axillary level in 42 SD rats. A nerve segment of 1 cm in length was harvested from the distal segment of each of the cut nerves right after the operation, 3 days, 1, 2, 3, 4 and 8 weeks postoperatively(group 1-7). The methods of Schwann cells culture and S-100 protein standing were used to study the temporal changes of the number of the Schwann cells, and the thickness of myelin of the predegenerated nerve were studied under electromicroscope. Results The number of Schwann cells increased after nerve transection, and reached a peak of [(3.52?0.27)?107]/ml in one week. The thickness of myelin also increased after nerve transection, and was thickest at about (231.2?8.9) nm in one week. The myelin thickness slowly decreased after this time. Conclusion The number of the Schwann cells and the thickness of myelin of the predegenerated nerve were changed with time.

Objective Attempt to find out the method of isolated purified Schwann cells from sciatic nerve of adult SD rat Methods Three methods of culturing Schwann cells from sciatic nerve of adult rats were compared: (1) Conventional primary explant technique in tissue culture (Method A) (2) Conventional enzymatic disaggregating technique for cell culture (Method B) (3) A modified method of cell culture (Method C): Test group: we dissected very carefully and separated the sciatic nerve into individual fibers under surgical microscpe, individual fibers were cut into 0 5～1 mm pieces and treated with enzymatic disaggregating by twoenzymes (0 5% Trpsin and 0 06% Collagenase) in 37℃ for 80～90 min Control group: a application of conventional enzymatic disaggregating technique for culturing the nerve adventital tissues, which werethe remaining procedures of Test group We applied immunohistochemistry method with S100 antibody and Fibroblast antibody to identify Schwann cells Function of these Schwann cells proliferated were assessed by MTT assay and H 3 Thymidine incorporation assay. Conclusion In method C, a pure culture of Schwann cells was obtained, where the two techniques were used: careful separation of the sciatic nerve into individual fibers and use of higher concentrations of two enzymes for longer time to digest the nerve tissues These two technigues can cleanly remove and inhibit the fibroblasts, and enable healthy and normal proliferation of Schwann cells

Objective To compare activated and normal Schwann cells in GAP43 gene expression. Methods 10 male SD rats, weighed from 100 g to 120 g. The right median nerve of SD rats was transected at the axillary level and was buried in muscle for predegeneration. 1 week later, the distal segment of the transected right median nerve with 1 cm long was harvested. The untreated left median nerve was harvested as control with same length. The epineurium of nerve was stripped, then the nerve tract was cut to small pieces. Schwann cells were obtained by way of double kinases digestion with 0.25% trypsin and 0.03% collegenase. The right median nerve was activated with additional liquid during digestion so as to obtain the activated Schwann cells. The normal Schwann cells were harvested from left median nerve. rt-PCR was used for GAP43 gene enlargement. mRNA was distilled from activated Schwann cells and untreated Schwann cells respectively. Then the mRNA was reversely transcripted to cDNA with SuperScriptTM, and cDNA worked as template for PCR enlargement. The product of PCR was separated with 1% agarose gel electrophoresis for 40 -50 min and stained with SYBR Green Ⅰnucleic acid gel. Fluorescence intensity of GAP43 PCR products was measured and then compared between the experiment group and control group. Results The Fluorescence intensity of GAP43 PCR product of activated Schwann cells was higher than that of normal Schwann cell. There was significant difference (P=0.003, Paired t test). It indicated that GAP43 mRNA of activated Schwann cells was much more than that of the normal Schwann cells. Conclusion GAP43 gene expression is up regulated in activated Schwann cells in contrast to normal Schwann cells. Activated Schwann cells secreting more GAP43, which may be one of the important mechanisms in promoting nerve regeneration.

BACKGROUND: New-type tissue engineering materials and post-proliferation Schwann cells are implanted into biosynthesis tube for repairing peripheral nerve defect, which are two great developments in the field of artificial biomaterial tube.OBJECTIVE: Taking chitosan-collagen as scaffold, activated Schwann cells as seed cells, we are in attempt to observe the affinity between them as well as growth rule of activated Schwann cells on Chitosan-collagen, so as to provide basis for pre-construction of artificial nerve.DESIGN: Open experiment.SETTING: Department of Hand Surgery, Huashan Hospital Affiliated to Fudan University.MATERIALS: This experiment was conducted at the Key Laboratory of Hand Function Reconstruction, Ministry of Public Health from July 2003 to December 2003. Four male SD rats, of clean degree, were used in this experiment. Chitosan-collagen film was made in Qisheng Biomaterial Technique Institute, Shanghai, Schwann cells activator solution was made in our laboratory (self-made).METHODS: After rats were anaesthenia, the sciatic nerve was cut off to perform predegeneration for 7 days. Another anaesthenia later, the rats were euthanized. Both sides of sorciatic nerves were cut off quickly and put in the D-HANK's solution containing penicillin and streptomycin.Epineurium was eliminated and chipped into 1 mm pieces, then put in the centrifuge tube containing 5 g/L trypsinase and 0.6 g/L collagenase. 0.5 mL activator solution every 2 mL liquid was added and the activated Schwann cells were harvested with the way of two-step enzymolysis. 2×107 L-1 activated Schwann cells in 200 μL were inoculated to Chitosan-collagen film and Petri dish . Two weeks later, cellular growth was observed under phase contrast microscope and scanning electron microscope. Cellular purity was identified with S-100 staining.MAIN OUTCOME MEASURES: ① Drawing cell growth curve and confirming in vitro doubling time. ②Observation of activated Schwanri cells under an inverted phase contrast microscope. ③ Observation of activated Schwann cells inoculated on Chitosan-collagen film under scanning electron microscope.RESULTS: ① Confirmation of in vitro doubling time: Concentration of activated Schwann cells inoculated on both Chitosan-collagen and Petri dish was 2×107 L-1, the final concentration was up to 3.0×108 L-1 and 2.0×108 L-1 respectively 2 weeks later. Doubling time of activated Schwann cells cultured on Chitosan-collagen film was 4 days calculated according to DT=(t-t0) lg2/(lgn-lgn0). ②Observation of activated Schwanncells under an inverted microscope: 24 hours later, the activated Schwann cells inoculated to Petri dish mostly changed from spherical to long shuttle-shape,mutation appeared and most were two-pole shape, fewer were three-pole shape; Morphologically, there was no significant difference between activated Schwann cells inoculated on Chitosan-collagen film and on Petri dish. Activated Schwann cells inoculated to Chitosan-collagen film were like "words cayed on the sand" under phase contrast microscope and the purity was over 95%. ③ Observation of activated Schwann cells inoculated to Chitosan-collagen under scanning electron microscope: Most of activated Schwann cells grew in the introcession of Chitosan-collagen or closely to surface of Chitosan-collagen, presenting regular head-to-end connection and adhesion to Chitosan-collagen film. The cell body was fusiform,with diameter of 4-6 μm, 60-80 μm in length. Cells were shuttle-shape with some small branches. Morphology of Chitosan-collagen film was still complete at week 1.CONCLUSION: There exists great affinity between Chitosan-collagen film and high-purity activated Schwann cell; so tissue-engineering scaffold made of the two components probably promote peripheral nerve regeneration.

ObjectiveTo investigate the effect of transforming growth factor-β1 (TGF-β1) antibody on peripheral neural fibrosis after chronic entrapment.MethodsA total of 75 rats were randomly divided into three groups, ie, Group A (sham operation, only the sciatic nerve exposed), Group B (compression only, treated with sciatic nerve entrapment) and Group C (compression plus antibody injection).Electron microscopy, immunohistoehemistry, RT-PCR and Western blot were performed to observe the morphological changes of the compressed nerve tissue and to determine the level of TGF-β1 , collagen Ⅰ and collagen Ⅲ at 2, 4, 6, 8, 10 weeks after sciatic nerve compression, respectively.Results The levels of TGF-β1 , types Ⅰ and Ⅲ collagen protein were increased significantly in the Group B compared with that in the Group A, when the expression of TGF-β1 was increased in the early phase of the compression, reached the peak at the 4th week, and then decreased slowly.The expressions of collagenⅠand collagen Ⅲ were increased after compression, reached a peak at the 6th week and then maintained a relatively high level.The number of the fibrous tissues was decreased significantly and the content of types Ⅰ and Ⅲ collagen protein declined in the Group C, with statistical difference compared with the Group B (P ＜ 0.05).ConclusionsPeripheral nerve fibrosis can be caused by chronic nerve compression.TGF-β1 plays an important role in effectively inhibiting the collagen synthesis and ameliorating the nervous fibrosis of the protein following peripheral nervous entrapment.

Objective To investigate the effects of connective tissue growth factor (CTGF) on the chronic peripheral nerve compression injury and explore the function of CTGF in peripheral nerve compression injury and repair. Methods From July 2010 to September 2010, fifty aduh male SD rats were randomly divided into group A and B: group A (sham-operated group): only exposed the sciatic nerve; group B (compression group): undergone sciatic nerve entrapment operation on the right hind leg according to the method which Mackinnon adopted when he established the model of chronic sciatic nerve compression.Electron microscopy,immunohistochemistry,RT-PCR and Western-blot were performed to observe the morphological changes of the compressed nerve tissue and to determine the level of CTGF,collagen- Ⅰ,Ⅲ (COL- Ⅰ,Ⅲ),2,4,6,8,10 weeks after the surgery,respectively. Results After sciatic nerve compression,the collagen in nerve increased ; The expression of CTGF and COL- Ⅰ, Ⅲ in sciatic nerve of compressed group increased, which was statistically different compared with the sham-operation group (P ＜ 0.05); In the meanwhile,the contents of CTGF and COL- Ⅰ,Ⅲ were positively correlated in a certain period. Conclusion Peripheral nerve fibrosis can be caused by chronic nerve compression.The expression of COL- Ⅰ,Ⅲ in sciatic nerve increased and CTGF get involved in the pathophysiological process, which suggests that CTGF plays an important role in the process of neural injury and fibrosis.

Objective To study the effect of Kangxian Ruangan Granule(KRG)on the collagen degradation in hepatic astrocytes(HA)at the cellular and molecular level.Methods The medicated sera of KRG was used to i ncubate the sub-cultured HA and sodium chloride and c olchicines were taken as controls.T he content of typeⅠcollagen in the cultured su-pernatant was measured with ELISA an d then was corrected by assaying the t otal protein in cell layer.The mRNA e xpres-sions of matrix metalloproteinase -1(MMP1)and tissue inhibitor of metalloproteinase -1(TIMP -1)were analyzed by semiquantitative RT -PCR.Results The content of typeⅠcollagen in the KRG -cultured supern atant was lower than that in the other two groups(P

OBJECTIVE:To evaluate the clinical effects of urapidil on cardiovascular response induced by sympathetic stimulation during front approach cervical vertebra operation.METHODS:One hundred and twenty patients undergoing front approach cervical vertebra operation were randomly divided into three groups.Patients in URA group treated with0.5mg/kg urapidil and patients in NIC group treated with5?g/kg nicardipine when systolic blood pressure(SBP)and heart rate(HR)increased by sympathetic nerve stimulation during the operation.And patients in COM group only increased their anesthesia degree with isoflurane at the same situation.The patients’SBP and HR were observed and compared among three groups at the time before the sympathetic nerve stimulation,and5minutes and10minutes after the drugs treatment respective?ly.RESULTS:The patients’SBP and HR in URA group had no significantly increase after administration of urapidil.In NIC group,although the patients’SBP had no significantly increase,the patients’HR increased significantly after nicardipine was used.But the patients’SBP and HR increased significantly after improved anesthesia degree with isoflurane.CONCLUSION:Urapidil has better effect on sympathetic cardiovascular response during the front approach cervical vertebra operation com?pared with nicardipine.

OBJECTIVETo seek new method for the treatment of peripheral nerve injury.

METHODSIn rat model with sciatic nerve defect, chitosan-collagen film was sutured into conduit to bridge 5 mm, 10 mm nerve defects. Rats that underwent end-to-end anastomosis were taken as controls. General observation, electrophysiological study, histological study and image analysis were performed at 4, 8, 12 weeks postoperatively.

RESULTSIn 5 mm nerve defects, the quality of nerve regeneration was similar to that of the control group. For 10 mm nerve defect, nerve regeneration was inferior to that of the control group. Chitosan-collagen film obviously degraded at 12 weeks postoperatively.

CONCLUSIONSChitosan-collagen film conduit can be used to bridge peripheral nerve defect.

Animals ; Biocompatible Materials ; therapeutic use ; Chitin ; analogs & derivatives ; therapeutic use ; Chitosan ; Collagen ; therapeutic use ; Male ; Models, Animal ; Nerve Regeneration ; Rats ; Rats, Wistar ; Sciatic Nerve ; injuries ; physiology ; surgery