BACKGROUND: Conventional opinions believe tissues of central nervous system(CNS) cannot regenerate after injury when they have been developed and maturated. However, recent researches have validated that neural stem cells exist in human and adult animal nervous system, and most of them are in static status in vivo. The therapeutic effects of neural stem cells in cerebral infarct have been a key point in the researches.OBJECTIVE: To observe the reactive process of endogenous neural stem cells after cerebral infarct to explore the effects of endogenous neural stem cell in CNS traumatic rehabilitation, which provides theoretical gist for the self-restoration after cerebral infarct.DESIGN: A randomized controlled trial by using experimental animals as subjects.SETTING: Department of Neurosurgery of Peking Union Hospital.MATERIALS: The study was conducted in the Laboratory of Neurosurgery Department of Peking Union Hospital from March to October in 2003. Totally 82 healthy male Wistar rats with a body mass between 250 g and 300 g were selected.METHODS: Cerebral infarct model was established in rats by thread-ligation method. Rats were divided into post-infarct 1 day, 3 days, 7 days, 14 days and 28 days groups with 14 rats each. Control group was sham-operation group( n= 12). The expressions of bromodeoxyuridine (BrdU) and Nestin in the brain of the rats were dynamically detected by immunohistochemical method.MAIN OUTCOME MEASURES: The changes of BrdU and Nestin positive cell numbers after cerebral infarct in rats.RESULTS: Only very few BrdU and Nestin positive cells had survived in hippocampal dentate gyrus and subventricular zone(SVZ) area in control group. BrdU positive cell significantly increased compared with control group in hippocampus and SVZ area after 1 day of cerebral infarct( P ＜ 0.05),which reached its peak on the 7th day( P ＜ 0.05), started to reduce after 14 days but still in the level significantly higher than normal( P ＜ 0.05), and closed to normal level after 28 days. And moreover, BrdU and Nestin positive cells were significantly more in infarct side than the opposite side ( P＜ 0.05), which migrated towards the opposite side through callus.CONCLUSION: Cerebral infarct can activate the proliferation in situ and migration of endogenous neural stem cell.