Objective To establish an in vitro cell co-culture model that simulates the transplantation environment in vivo ,and to investigate the effect of primary cells from neonatal cortex on the differentiation of PC12 cells. Methods PC12 cells were transfected with pEGFP-N1 vector to express green fluorescent protein (GFP) stably,then these cells were transplanted into primary neurons and glial cells from neonatal cortex. Cultures with PC12 cells alone constituted the control group. Nerve growth factor (NGF) was added into all the other cultures to induce neuronal differentiation of the PC12 cells. Neurite outgrowth of the neuronal PC12 cells was observed with laser confocal microscopy. Results Comparing with the control group,the PC12 cells co-cultured with primary neurons and glial cells showed higher differentiation rate (57.13% to 67.77%,P

Objective To clone injury-regeneration-related genes after primary neurons of spinal cord were injured in rat, and to elucidate the molecular mechanism of injury and regeneration in CNS. Methods An in vitro spinal cord primary neuron injury model was replicated in rat. The differentially expressed genes during injury and regeneration periods of spinal cord primary neurons were cloned by improved subtractive hybridization. Results Twenty-seven differentially expressed sequences were obtained, 23 were known genes and the others were unknown. Among these known sequences, cDNA for synuclein and clusterin, together with several other gene sequences, were closely related with nerve degenerative diseases. Conclusion Primary neuron injury-regeneration-related genes of the spinal cord can be successfully cloned by improved subtractive hybridization.

Objective To investigate the apoptosis rate of neurons in vitro among the primary culture cells isolated from rat spinal cords before and after injury. Methods The spinal cord neurons of Wistar rats at 14-day gestation were isolated and cultured. The neuronal processes were then injured by cutting. At different time points after injury, TUNEL method was employed to detect the apoptotic neurons. Results Before injury, there was almost no apoptotic neuron. However, a large amount of apoptotic neurons were observed after the injury. The highest incidence of apoptosis appeared on the first day, and then it gradually reduced in the following days, but increased in amount again on the seventh day. Conclusion The results of the present experiment reveal the regularity of apoptosis of neurons before and after injury, and it provides a platform for further research regarding therapeutic intervention in the treatment of spinal cord injury.

Objective To establish a model of injury to primarily cultured spinal cord neurons,mimicking the neuronal injury after complete transactional spinal cord trauma,for the sake of exploring changes in expression of an immediately-early gene,c-jun,in central nervous system injury. Methods Spinal cords were removed form fetal Wistar rats at the 14th gestation day and the neurons were cultured for 10 to 12 days.Then,mechanical injury was applied to the neurons by making regular scores on the culture disk under direct vision with the aid of a self-made standard template.Morphology of the injured neurons and changes in expression of c-Jun protein were observed before and at different intervals after injury. Results c-Jun expression was noted in neuronal nuclei 10 min after injury and its peak appeared at 2 hrs.Besides,the density of positive neurons bore evidently an inverse proportion with their distance from the scores.Conclusion\ Positive expression in injury neurons show that c-jun gene enters the nucleoli of injured neurons and takes the role of “the third messenger” at early time after neuronal injury.

BACKGROUND: Hepatocyte growth factor (HGF) promotes neurite outgrowth from neocortical explants, and supports neuronal survival under serum-free condition. Thus, HGF can mediate neurotrophic function as a novel neurotrophic factor.OBJECTIVE: To establish an in vitro injury model with a semi-solid culture system for the purpose of improving the evaluation of neurite regeneration of transected spinal cord neurons from rat embryo, and investigate the effect of HGF on neurite regeneration.DESIGN: Randomized controlled study.SETTING: Hematology Laboratory of Radian Medical Institute of Academy of Military Medical Sciences of PLA.MATERIALS: The experiment was carried out at the Hematology Laboratory of Radian Medical Institute of Academy of Military Medical Sciences of PLA from August 2004 to May 2005. Wistar fetal rats of 14-16 days old were provided by Animal Center of Academy of Military Medical Sciences of PLA. Tail collagen was extracted from adult male Wistar rats with body mass of (250±50) g.METHODS: ① Rat tail type Ⅰ collagen substrate was prepared and spread on a culture dish, cut into about 0.5-1.0 mm3 slices, then spinal cord slices of 15-day-old fetal Wistar rat were explanted on the primary culture. Five days later, the outgrowing processes were severed, then a block of collagen, with the surface area of 2 mm2 and 200 μm away from the slice, was removed and the vacancy was replaced with a fresh collagen block of 2 μL after aspirating the medium. The fresh collagen block could be solidified and then fresh liquid medium was added as the secondary culture. The regeneration of neurite was observed by microscopy at 0, 1, 6,12 and 24 hours after severing. ② The medium was changed with 0.5% N3-conditioned medium. 10 μg/L HGF was added in the experimental group, and 0.5% N3-conditioned medium was added in the control group.The status of regeneration was evaluated by the average value of 3 longest regenerative neurites for each slice. There were 12 slices in each group.The status of neurite regeneration was calculated and was evaluated 24 hours later.MAIN OUTCOME MEASURES: ① neurite regeneration in situ; ②comparisons of neurite regeneration between control group and experimental group.RESULTS: ① Neurite regeneration in situ: The neurites disintegrated near the severing line immediately following the transection injury. This process persisted about 1-2 hours and the distance away from the severing line was about 20 μm. Then the proximal end of neurites would swell and thicken. At this time neurites stopped collapsing and neurite regeneration began. Their regenerating rate would quicken at 12 hours after severing. Regenerating neurites were more branching and curlier as compared with original neurites. ② Comparisons of neurite regeneration between control group and experimental group: The average length of regenerative neurites was more in the experimental group than that in the control group [(375±96) μm, (200±75) μm, P ＜ 0.05].CONCLUSION: ① We establish a simple, economic model to evaluate neurite regeneration. ② By this model, we prove that HGF can promote neurite regeneration.

Objective To explore the protective effect of HGF on primary cultured spinal neurons in vitro.Methods Cultured neurons were transfected with Ad-GFP or Ad-HGF in different multiplicity of infection(MOI),then flow cytometer and PI-Hoechst double stains were used to assay transfer rate or to determine the status of cells respectively.ELISA was used to detect the expression of HGF in Ad-HGF transfected neurons,and the activity of neurons was judged by neutral red stain,MTT and NSE-ELISA methods.Results After transfection with Ad-GFP in MOI of 50,the transfer rate was high as detected by flow cytometer,and the status of cells was well as judged by PI-Hoechst double stain.The results of ELISA showed that HGF was expressed in medium.After transfection with Ad-HGF,the activity of neurons was better than neurons without treatment(P

Objective To provide the candidate antigens for immunological diagnosis by analyzing the expression of nu -cleoprotein ( NP) of Ebola virus. Methods BioSun software was used to predict the NP epitopes. The bridging-PCR was used to synthesize the NP gene. The pBVIL1 vector was used to clone and express the NP gene. Results The 360-739 aa of NP was confirmed to be the dominant antigen by BioSun software. The recombinant NP dominant antigen was expressed in E.coli with molecular weight of 58 ×103.The specificity of ELISA based on recombinant NP was 99.24% (130/131) in negative samples. Conclusions The dominant NP antigen can be potentially used for developing Ebola virus diagnostic reagent.

Objective To develop an antigen retrieval method for detection of human mammaglobin ( hMAM) immuno-histochemcal staining in old paraffin-embedded specimens .Methods The tissue sections in test group were put into dis-tilled water after deparaffinization and then moved into citric acid buffer ( pH 3.5) for 10-15 min.The other two meth-ods,microwave method and high pressure cooker method ,were compared as control groups at the same time .Finally, immu-nohistochemistry SP method was used to check the antibody in the sections .Results The color appearance in the test group (pH 3.5 citric solution) was better than that of microwave oven and high pressure cooker groups .In the test group, tissue sections were not easily cast off from the slices .Conclusion In this study,we have established a new and simple antigen retrieval method which will contribute to immunohistochemistry technology .

Spinal cord injury and regeneration involves transcriptional activity of many genes, of which many remain unknown. Using the rat spinal cord full- transection model, bioinformatics, cloning, expression assays, fusion proteins, and transfection techniques, we identified and characterized one such differentially expressed gene, termed scirr1 (spinal cord injury and/or regeneration related gene 1). Fourteen orthologs were found in 13 species from echinoderm to insect and human by Blast search of NCBI protein reference sequence database. However, no further information is available for these homologues. Using whole-mount in situ hybridization, mouse scirr1 mRNA was expressed temporally and spatially in accordance with the early development sequence of the central nervous system. In adult rat spinal cord, expression of scirr1 mRNA was localized to neurons of gray matter by in situ hybridization. Using immunohistochemistry, SCIRR1 protein was found to be up-regulated and expressed more highly in spinal cord neurons farther from the epicenter of injury. Although the precise function of SCIRR1 is unknown, its unique pattern of expression during CNS early development and up-regulation after spinal cord injury suggest that SCIRR1 should be involved in the succeeding injury and/or repair processes of the injured spinal cord. Also, the typical F-box and leucine-rich repeat (LRR) architecture of rat SCIRR1 indicated that it may play an important substrate recruiting role in the pleiotropic ubiquitin/proteasome pathway. All these make scirr1 a new interesting start to study the spinal cord injury and regeneration mechanism.
Amino Acid Sequence ; Animals ; Base Sequence ; Brain/embryology/metabolism ; Embryo, Mammalian/metabolism ; F-Box Proteins/*biosynthesis ; Gene Expression Regulation, Developmental ; Male ; Mice ; Molecular Sequence Data ; Organ Specificity ; PC12 Cells ; Phylogeny ; Rats ; Rats, Wistar ; Spinal Cord/embryology/metabolism ; Spinal Cord Injuries/*metabolism ; Up-Regulation