Ependymal/subventricular zone cells migrate to the peri-infarct region and differentiate into neurons and astrocytes after focal cerebral ischemia in adult rats.

Objective: To investigate the migration and differentiation of ependymal/subventricular zone cells after focal cerebral ischemia in rats, and reveal the origin of the newly generated neural cells in the peri-infarct region.
Methods: Normal adult male Sprague Dawley rats weighing 250-350 g were used in this study. Before middle cerebral artery occlusion (MCAO), 10 microl of 0.2% DiI was injected into the lateral ventricle for prelabeling the ependymal/subventricular zone cells. After ischemia, cumulative BrdU labeling was employed to detect the newly generated cells and double immunofluorescent staining to identify cell differentiation. The labeled cells were observed with laser confocal microscopy.
Results: In the non-ischemic control rats, DiI-labeled cells resided in the ependyma/subventricular zone. After focal cerebral ischemia, DiI-labeled cells were found in the corpus callosum, adjacent striatum and cortex, and some DiI/BrdU/glial fibrillary acidic protein (GFAP)-positive cells or DiI/BrdU/ neuronal nuclear antigen (NeuN)-positive cells were observed in the peri-infarct region in the striatum or cortex since day 14 after MCAO.
Conclusion: After focal cerebral ischemia, ependymal/subventricular zone cells migrate into the peri-infarct region where they differentiate into neurons and astrocytes. This finding may be important for understanding the source of adult neural stem cells and for developing new therapeutic intervention strategy through enhancing endogenous neurogenesis after brain injury.