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Objective To explore the effect of arsenic trioxide (As2O3) on the migration of neurons and the potential mechanism through the establishment of primary neuron culture from the brains of neonatal rats.Methods Brain tissues were selected from SD neonatal rats for primary neuron calture.The cells were divided into 4 groups based on the addition of As2 O3:normal control group,1 μmol/L As2O3 group,10 μmol/L As2O3 group and 20 μmol/L As2O3 group.The primary neurons were treated with different concentrations of As2O3 and cultured for 24 hours.Boyden chamber assay was used to detect the effect of As2O3 on neuronal migration.Immunofluorescence laser confocal microscope was used to observe the structure of actin.Results In the control group,the cultured neurons showed a regular pattern of distribution.In the 3 groups treated with As2O3,the distribution of neurons was loose and disordered,which was most obvious in the 20 μmol/L As2O3 group.The results showed that the higher concentration of As2O3,more difficult it was for the neurons to survive.The number of neuronal migration was 64.6 ± 4.3 for normal control group,63.0 ± 7.0 for 1 μmol/L As2O3 group,54.8 ± 3.6 for 10 μmol/L As2O3 group,and 21.6 ± 3.9 for 20 μmol/L As2O3 group.The results showed that As2O3 might inhibit the migration of primary neurons in a dose-dependent manner (F =49.31,P ＜0.001).The normal actin skeleton was destroyed under the laser confocal microscope in 10 μmol/L As2O3 group and 20 μmol/L As2O3 group,while they remained unaffected in normal control group and 1 μmol/L As2O2 group.Conclusion As2 O3 exposure can reduce the neuron migration in a dose-independent manner probably through disrupting the organization of acting cytoskeleton.
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Objective To study the neurogenesis after focal cerebral ischemia in the dentate gyrus of adult rats and the mechanisms responsible for stroke-induced neurogenesis.Methods Animal models of middle cerebral artery occlusion(MCAO) were established in 16 adult rats,and four of another 8 rats served as normal control and four underwent sham operation.Doublecortin was used to label neuron precursors.The proliferation rate of neuron precursors in the dentate gyrus on day 1,7,14,21 after reperfusion was examined.Results The doublecortin-positive cells in the ipsilateral dentate gyrus and contralateral dentate gyrus reached the highest level on day 7 after reperfusion,up to 2.4-fold higher than that of sham-operated rats(P
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0.05). The expression of GFP was located around the ventricle and persisted for a long time. Conclusion The fluorescence of GFP is stable and persistent and the GFP has no negative effects on the NSCs-GFP. It is an ideal maker of neural stem cells and could be used for the study of NSCs transplantation.
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Objective To study the migration of neuronal precursors around the infarct area after focal cerebral ischemia.Methods Animal models of middle cerebral artery occlusion(MCAO) were established in 16 adult rats,and four of another 8 rats served as normal control and four underwent sham operation.Immunohistochemistry and cell count were applied to explore and contrast the migration of neuronal precursors for up to three weeks after a 2-hour episode of focal cerebral ischemia.Results The migration of neuronal precursors toward the infarct area could be found at various timepoints.The number of neuronal precursors started to increase in 1 d after reperfusion around the infarct area and reached the peak in 7 d,then declined till day 21.However,the neuronal precursors could not be examined in the corresponding non-ischemia area.Conclusion The neuronal precursors could migrate into the ischemic penumbra.It indicates that after cerebral ischemia,neuronal precursors are directed toward the sites of brain injury,where they might be in a position to participate in brain repair and functional recovery.
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Objective To investigate the migration pathway and feature of neuronal precursors in normal adult rats and provide theory and experiment basis for the neuronal migration under pathological condition. Methods The adult rat brains were cut into 20 ?m coronal and sagittal sections on a freezing microtome. Immunohistochemistry was applied to observe the migration pathway and feature of DCX-expressing cells. Results There were two migration pathways with the neuronal precursors in normal adult rats. One was the rostral migratory stream (RMS) from the subventricular zone to the olfactory bulb, another appeared to travel in a chain along the interface between cortex and corpus callosum. The DCX-positive cells in the RMS had the fusiform somata with a single leading process and the process orientated to the olfactory bulb, while the DCX-positive cells around the corpus callosum had similarly round somata and the size, number and orientation of process were of diversity.Conclusion The study of neuronal precursors migrating not only contributes to identify the migration mechanisms, but also contributes to the control of neuronal migration and designs some effective therapy strategies.