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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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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.