The present study investigated different types of eoexpression of brain derived neumtmphic factor(BDNF),nerve growth factor(NGF)and neutmphin-3(NT-3)mRNA and/or proteins in the left sixth lumbar dorsal root ganglion(DRG)of cats and discuss themechanism of coexpression in order to provide foundation for elucidating the relationship between the expression of neurotrophic factors andspinal cord plasticity.The eats used in this study were normal animals without any interventional treatment.They were subjected to renloveof the left L6 DRG and their DRG were processed for immunohistechemistry and in situ hybridization double staining to observe whetherthere are coexpression of mRNA and proteins of BDNF,NGF and NT-3.The results showed that the pmteios and mRNA of BDNF,NGFand NT-3 were all expressed in the DRG of cats,but the types of coexpression of mRNA and proteins were different and diverse amongthese three neumtrophic factors.The results of immunohiatochemistry showed that BDNF immunoreactivities were mainly observed in thecytoplasm and nucleus,and the staining of nucleus was weaker than that of cytoplasm;NGF immunoreactivities were mainly observed innucleus while NT-3 mainly in cytoplasm.The results of in situ hybridization showed that BDNF and NGF positive signals mostly distributedin the cytoplasm,NT-3 positive signals were observed in both the cytoplasm and nucleus.Our results suggest that the proteins and mRNAof BDNF,NGF and NT-3 have different types of coexpression which indicate they may have autocrine and/or paracrine mechanism contrib-uting to the plasticity of spinal cord in the left L6 DRG of cats.

Objective To establish a serial of stable and mature methods of primary culture hippocampus neurons of GFP-transgene embryonic mice,to get the morphologic data of cultured neurons.Based on this research,in future,we can give an important theoretical and practical support for the therapy of nervous system diseases by transplanting with hippocampus neurons of GFP-transgene embryonic mice.Methods We primarily cultured the hippocampus neurons derived from the GFP-transgene embryonic mice in vitro.Under the microscope,we found cultured hippocampus neurons could live for more than one month and appeared to be the best status in 5～7 d after culture.During this time,the processes of the neurons are thick and the neurons connected one another to form the"cells-net" through their processes.After 14 d,the growth of the hippocampus neurons became slow.Results A serial of culture methods of hippocampus neurons had been successfully established.These cultured neurons were identified by the immuno-histochemical methods.They grow well in different phases before 14 d after culture.Conclusion Culturing hippocampus neurons of GFP-transgene embryonic mice is a simple,stable and effective method which can be applied to scientific research by other researchers.

Objective To observe the effects of global ischemia-reperfusion on inhibitory synaptic function in hippocampal CAl region of adult rats.Methods Animals were randomly divided into three groups: sham-operation group(SH),ischemia-reperfusion 3 day(IR-3) and 7 day group(IR-7).Global ischemic episode was achieved by 4-vessel occlusion.Evoked inhibitory postsynaptic currents(eIPSCs) were recorded from CA1 pyramidal cells in hippocampal slices using whole-cell voltage-clamp.Results The eIPSCs amplitudes generated by lower stimulus intensities were significantly decreased in both IR-3 and IR-7 rats as compared with SH rats.Moreover,the rise time of eIPSCs in IR-7 group was significantly decreased as compared with SH group(P

To explore the characteristic features of morpho logical changes of neurons in the spinal dorsal horn result from different types of spinal cord in jury, the adult Srague-Daweley fat models of crushed, hemi-sected and transected spinal cord injury established in our laboratory were used, and the intact spin al cords were as control． 　　These rats were sacrificed after 24 hours, 7 days and 2l days of operation, and the L3, segments were removed out and sectioned continuously into sections of 20 μm in thickness． The sections were stained by hematoxylin and observed under ． 　　 microscope． In addition, neurons in the dorsal horn were counted． 　　 Results: In the crushed spinal horns, bodies of neurons were atrophy, but neuron counting did not decrease markedly; in the hemi-sected and transected dorsal horn, a batch of empty cavities were presented, and neuron counting decreased greatly． The results indicated that different injuries of spinal cord resulted in different damage to neurons in the dorsal horn, i． e． the crushed one, the bad, the hemi-sected one, the worse; and the transected one, the worst．

AIM: The aim of this study was to explore the expression of nerve growth factor(NGF) in spinal dorsal horn following crushed spinal cord injury. METHODS: The adult Srague-Dawley rat model of crushed spinal cord injury was established by the method in our laboratory, and intact spinal cord was used as control. The rats were sacrificed respectively after 24 hours, 7 days, and 21 days of operation, and the L3 spinal segments were removed out and fixed in 4% polyformaldehyde. The segments were sectioned into sections of 20 μm in thickness. The sections were stained with anti-NGF antibody by ABC method of immunohistochemistry technique. The immunoreactive intensity of NGF and the number of positive neurons as well as glial cells in dorsal horn were observed and counted under light microscope. RESULTS: The number of positive cells and immunoreactive intensity of NGF increased gradually in the dorsal horn at 24 hours, 7 days and 21 days following crushed spinal cord injury compared with control group (P＜0.01). CONCLUSION: These results indicated that NGF plays an important role in the postoperative reaction during the early period of the crushed spinal cord injury.

AIM: It is well known that different injuries will result in different consequences. In this paper, we investigated the morphological change of spinal cord following crushed, hemi-sectioned and transected injury. METHODS: Sixty Wistar rats were randomly divided into 4 groups: intact group, crushed spinal cord injury group (cSCI), hem-sectioned SCI group (hSCI) and transitioned SCI group (tSCI). The models of SCI were established by the method in our laboratory. The animals in each group were sacrificed respectively at 24 hours, 7 and 24 days after operation. The L2 spinal cord which located in the caudal of injury site was taken respectively from each animal in each group and sectioned into frozen sections (20 μm). The sections were stained by hematoxylin and observed under light microscope. The number of neurons in dorsal and ventral horn was also counted. RESULTS: In cSCI group, some neurons appear to atrophy compared with that of intact group, but the number of neurons did not decrease apparently than that of intact group (P＞0.05). Comparatively, some cavities were observed in dorsal and ventral horn in hemi-sectioned and transitioned SCI group. And the number of neurons in dorsal horn and ventral horn decreased greatly at 24 hours, 7 and 21 days compared with intact group (P＜0.05). The results indicated that the decrease of neuronal number in dorsal horn and ventral horn after injury resulted from hSCI and tSCI, but not from cSCI. As a result, some different strategies should be considered for different injuries. For example, some neurotrophic factors may be useful in cSCI, but, many neurons have disappeared following hSCI and tSCI, therefore, other strategies that increase the number of neurons should be considered too. CONCLUSION: Our results provide the important morphological evidences on the change of spinal cord following cSCI, hSCI and tSCI. The data will be useful in treatment of SCI in the future.

Objective To study the early expression of ca]pain Ⅱ and microtubule associated protein 2 (MAP2) mRNA in the hippocampus of the lateral fluid percussion injury rats. Methods 18 Male Sprague-Dawley rats were randomly divided into 3 groups. The changes of Calpaln Ⅱ and MAP2 mRNA in hippocampus 3 h after injury were detected by real-time PCR. Results Compared to the control group (n = 6), the expression for Ca]pain Ⅱ mRNA increased obviously(P <0.01)in the lateral fluid percussion injury group(n=6) ,the expression for MAP2 mRNA degraded obviously(P <0.01). Compared with the lateral fluid percussion injury group(n =6) ,the expression for calpuin Ⅱ mRNA in the mild hypothermia group degraded obviously (n = 6), the expression for MAP2 mRNA increased obviously(P <0.01). Conclusion Mild hypothermia may act as neuroprotection by inhibiting the expression of Ca]pain Ⅱ and easing the degradation of cytoskeleton.

BACKGROUND: Marrow stromal cells (MSCs) own the characteristic of migration. However, the mechanisms underlying the migration of these cells remain unclear. OBJECTIVE: To explore the roles of stromal cell-derived factor-1 (SDF-1) and its receptor CXCR4 in trafficking of MSCs migration. DESIGN, TIME AND SETTING: The in vivo cytology experiment was performed at Department of Anatomy, National University of Singapore from March 2007 to June 2007. MATERIALS: MSCs were isolated and purified from a Wistar neonatal rat. Forty adult female Wistar rats were randomly divided into sham operation and experimental groups, with 20 animals in each group. METHODS: The chemotaxis assay was performed at a 48 well Boyden chamber, and a total of 25 μL SDF-1 was added to the lower layer of chamber, covered with 8 μm polycarbonate membrane filter; SDF-1 cultured in DMEM conditioned medium was served as a blank control group. Cell concentration was regulated to 1.5×109L-1/L. 50 μL and cell suspension was added into the upper layer of chamber, cultured at CO2 incubator with temperature of 37 ℃ for 10 hours. Rats in the experimental group were prepared for transected spinal cord injury models, and in the sham operation'group, only the vertebral plate was opened. 1.0 mL (1×109L-1/L) MSCs suspension labeled with 5-(and-6)-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE) was injected through internal jugular vein at 1 hour after completely transected spinal cord. MAIN OUTCOME MEASURES: Expression of chemokine receptor CXCR4 in MSCs, as well as the effect of SDF-1 on the migration of MSCs was observed by immunofluorescence, change of SDF-1 in lesion site of spinal cord was detected by real-time PCR analysis, as well as the in vivo migration of intravenously injected MSCs was detected by fluorescence microscopy. RESULTS: The pudfied MSCs were positive to CXCR4. Compared to the blank control group, SDF-1 with concentrations of 5, 50, and 500 μg/L could accelerated the migration of MSCs (P < 0.05), which reached a peak with concentration of 500 μg/L. The expression of SDF-1 RNA was obvious increased in the experimental group than that of the sham operation group (P < 0.05), and returned to a normal level at 14 days. At 2 weeks after cell injection, the number of MSCs migrated to the lesion site of completely transected spinal cord was significant increased than sham operation group (P < 0.05). CONCLUSION: SDF-1 may contribute to MSCs migration in vitro and in vivo. SDF-1 and its receptor CXCR4 are involved in the migration of injected MSCs to the lesion site of completely transected spinal cord.Ding P, Xue LP, Yang ZY, Wang CQ, Wang JH, Feng ZT, Ling EA.Chemokine stromal cell-derived factor-1 and its receptor CXCR4 mediate migration of marrow stromal ceils into the lesion site of completely transected spinal cord.

BACKGROUND: Auditory evoked potential P50 (AEP-P50) is a cerebroeilectrophysiological index to directly reflect normal inhibitory function of brain.OBJECTIVE: To observe the changes of AEP-P50 of sensory gating (SG)in model rats with Alzheimer disease (AD).DESIGN: Randomized controlled animal study.SETTING: Neuroscience Institute of Kunming Medical College.MATERIALS: A total of 24 healthy female SD rats, aged 4-6 months,weighing 200-300 g, were randomly divided into experimental group, control group and normal group with 8 in each group. Morris water maze was consisted of round pool and lucite plant. Pool was divided into platform,left, right and bilateral quadrants. METHODS: The experiment was carried out in the Neuroscience Institute of Kunming Medical College from September 2003 to March 2005. ① Experimental group: Bilateral fimbria-fornix was transected to induce AD models; control group: Except fimbria-fornix, cortex and callus were transected; normal group: Rats were not treated with any operation. ② One week after modeling, all rats were tested with Morris water maze which contained localizing navigational ability and spatial seeking ability in order to determine successful models. Each rat was trained 4 times a day for successive 5 days. The duration from putting in pool to finding out platform was regarded as the escape latency (EL) which could reflect localizing navigational ability. Swimming trace of rats which searched platform within 1 minute could reflect spatial seeking ability. ③ AEP-P50 was recorded with "condition (C)-test (T)" auditory double clicks stimuli, additionally,differences of AEP-P50 among the three groups were compared at the same time. C-P50 amplitude, T-P50 amplitude, T/C and absolute value of difference of S2-S1 amplitude were calculated. Measurement data were compared with one-way analysis of variance among groups and with t test intergroup.MAIN OUTCOME MEASURES: ① Morris water maze, I.e., comparison between localizing navigational ability a nd spatial seeking ability; ② comparison of AEP-P50 of rats among three groups.RESULTS: All 24 rats were involved in the fin al analysis. ① results of Morris water maze: With increase of training time, mean latency was shortened. The latency was decreased in the first 3 days and then stabilized gradually. Latency in experimental group was longer than that in normal group and control group (P ＜ 0.05). Swimming traces in normal group and control group were located at platform quadrant, and they were accounted for 45.23% and 39.7% of total quadrant, respectively. There was significant difference as compared with other quadrants (P ＜ 0.01). Swimming traces of rats in experimental group were accounted for 28.31%, 29.84%,20.47% and 21.38% in platform, right, bilateral and left quadrants, respectively; however, there was not significant difference (P ＞ 0.05). Swimming trace was randomly located in four quadrants. ② Results of AEP-P50 of SG: C-P50 amplitude and absolute value of difference of S2-S1 amplitude were (21.00±2.85), (15.26±4.07) μV in control group and (17.04±5.32), (10.85 ±4.24) μV in normal group, which were obviously higher than those in experimental group [(9.67±3.77), (2.89±2.61) μV, P ＜ 0.01].T-P50 amplitude and C-P50 amplitude were 0.25±0.18 in control group and 0.39±0.16 in normal group, which were lower than those in experimental group (0.92±0.41, P ＜ 0.01).CONCLUSION: ① Transection of bilateral fimbria-fornix can be used to establish AD animal models successfully. ② AD model rats whose bilateral fimbria-fornix is transected have deficiency of SG.

The present study aims to isolate neural stem cells from neonatal rat hippocampus and induce them to differentiate into cholinergic neurons. A multipotent cell line derived from the hippocampi of neonatal rats which had the ability to form clones was incubated in serum-free DMEM/F12 medium added with 20ng/ml basic fibroblast growth factor (bFGF) and B27. After differentiation of the neural stem cells, immunocytochemistry was used to detect nestin, the antigen of the cell clone, and β-tubulin (Tuj 1 ), glial fibrillary acidic protein (GFAP) and galactocerebroside (Galc), the markers specific for neurons, astrocytes and oligodendrocytes, respectively. Embryonic chick skeletal muscle extract was used to induce the differentiation of the neural stem cells into cholinergic neurons. The results showed that the cell line isolated from the hippocampi of neonatal rats expressed nestin and had the potential to form clones and differentiate into neurons, astrocytes and oligodendrocytes. Embryonic chick skeletal muscle extract can induce 9.6% of the isolated cell line to differentiate into cholinergic neurons compared with 3.9% in controls. These findings suggested that the cell line, which expressed nestin antigen, was a multipotent cell line capable of self-renewing, and was believed to contain stem cells of the CNS. These neural stem cells can be induced to differentiate into cholinergic neurons by using embryonic chick skeletal muscle extract.