Cell proliferation in ependymal/subventricular zone and nNOS expression following focal cerebral ischemia in adult rats.
Neuronal nitric oxide synthase (nNOS) regulates neurogenesis in normal developing brain, but the role of nNOS in neurogenesis in the ischemic brain remains unclear. To investigate the temporal and spatial relationship between cell proliferation of the ependymal/subventricular zone (SVZ), a principal neuroproliferative region in the adult brain, and nNOS expression, the male Sprague-Dawley rats weighing 250-350 g were used. The focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). 10 microl of 0.2% fluorescence dye DiI was injected into the right lateral ventricle to prelabel ependymal/subventricular zone cells before ischemia. The rats were killed immediately after ischemia and days 1, 3, 7, 11, 14, 21 and 28 after ischemia. DiI-labeled cell counting was employed to assess cell proliferation. Immunohistochemistry and grayscale analysis were performed to determine nNOS localization and its quantity in the specific regions. Compared with control, the density of DiI-labeled cells in the ipsilateral ependyma/SVZ was significantly higher at days 1, 3, 7 and 11 after ischemia, whereas the quantity of nNOS expression in the ependyma/SVZ adjacent regions was significantly lower at the above time points. Additionally, nNOS positive cells were largely excluded from SVZ, and their long processes did not enter the ependyma/SVZ. Our results indicate that after focal cerebral ischemia, decreased nNOS expression in the ipsilateral ependymal/SVZ adjacent regions might be related to cell proliferation in the ependymal/SVZ.
Zhang
Pengbo
P
Research Center for Neuroscience, Environment and Genes Related to Diseases Key Laboratory of Education Ministry, School of Medicine, Xi'an Jiaotong University, China.
Liu
Yong
Y
Li
Jie
J
Kang
Qianyan
Q
Tian
Yingfang
Y
Chen
Xinlin
X
Shi
Qindong
Q
Song
Tusheng
T
D000818:Animals; D002545:Brain Ischemia / Q000201:enzymology / Q000473:pathology*; D002232:Carbocyanines; D002452:Cell Count / Q000379:methods; D049109:Cell Proliferation; D002552:Cerebral Ventricles / Q000378:metabolism / Q000473:pathology*; D004195:Disease Models, Animal; D004805:Ependyma / Q000201:enzymology* / Q000473:pathology*; D015870:Gene Expression / Q000502:physiology; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D013997:Time Factors
C035005:3,3'-dihexadecylindocarbocyanine; D002232:Carbocyanines; D052248:Nitric Oxide Synthase Type I