PROLIFERATION AND DIFFERENTIATION OF NEURAL STEM CELLS IN THE SUBVENTRICULAR ZONE AND SUBGRANULAR ZONE IN OLD RATS AFTER FOCAL CEREBRAL ISCHEMIA

Objective The proliferation and differentiation of neural stem cells in the subventricular zone(SVZ) and subgranular zone(SGZ) have been observed in normal old rats or treated by middle cerebral artery occluded(MCAO) and sham operation respectively. Methods Old rats were used to make models of middle cerebral artery occluded(MCAO).By BrdU pulse labeling and immunohistochemical single staining,the change of the number of BrdU positive cells was observed in SVZ and SGZ of normal rats or cerebral ischemia rats after MCAO 3d,7d,14d,21d,28d and sham operation respectively.By BrdU accumulating label and immunohistochemical double staining,BrdU/NeuN and BrdU/GFAP positive cells were determined in SVZ and SGZ of aged rats after MCAO 14d. Results BrdU positive cells were found in bilateral SVZ and SGZ of all groups above mentioned.Compared with normal and sham groups,BrdU positive cells of SVZ and SGZ in cerebral ischemia rats were strikingly increased.BrdU positive cells reached the peaks in SVZ at 7d and in SGZ at 14d after MCAO.At 14d after MCAO,BrdU/NeuN(0.98%) or BrdU/GFAP(12.56%) double labled cells were observed in SVZ,but no double labled cell was observed in SGZ.Conclusion The focal cerebral ischemia markedly stimulated proliferation of neural stem cells in SVZ and SGZ in old rats,and some proliferative cells in SVZ can differentiate into neurons or glial cells.