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目的:脑内成体干细胞状态和年龄的关系非常密切,本研究探讨小鼠老化过程中脑室下区(subven-tricular zone,SVZ)内成体干细胞随年龄增加增殖活性的变化和脑内β-catenin信号的相关性。方法:C57B/L小鼠分别饲养至2,12,18月时处死,各组动物处死前腹腔注射BrdU(60 mg/kg,处死前3 d开始注射,连续注射3 d,1次/d)。部分动物断头取脑,冰台上游离前额皮层,冷冻备用,部分动物灌注固定,连续冠状冰冻切片备用。利用免疫组织化学方法检测SVZ区BrdU和Ki67表达。利用Western blot技术检测前额皮层内β-catenin的表达水平。结果:12,18月时小鼠SVZ区BrdU和Ki67阳性细胞的数量与2月时比较明显有所减少(P<0.05)。Western blot结果可见前额皮层内β-catenin的表达水平在2月时达高峰,12月和18月时逐渐减少。结论:SVZ区干细胞的增殖能力随年龄增加逐渐下降可能与脑内β-catenin信号的减弱有关。
OBJECTIVE: The relationship between adult stem cell status and age in the brain is very close. In this study, the changes of proliferative activity of adult stem cells in the subventricular zone (SVZ) and the β-catenin signal Relevance. Methods: C57B / L mice were sacrificed at 2, 12, and 18 months respectively. Animals in each group were injected intraperitoneally with BrdU (60 mg / kg ip 3 days before injection, . Some animals decapitated brain, ice table free forehead cortex, frozen standby, fixed perfusion of some animals, continuous coronary frozen section for use. The expression of BrdU and Ki67 in SVZ was detected by immunohistochemistry. Western blot was used to detect the expression of β-catenin in the prefrontal cortex. Results: The number of BrdU and Ki67 positive cells in SVZ of mice in 12 and 18 months decreased significantly compared with that in February (P <0.05). Western blot results showed that the expression level of β-catenin in the prefrontal cortex peaked in February and gradually decreased in December and 18 months. CONCLUSIONS: The proliferation of stem cells in SVZ gradually decreases with increasing age, which may be related to the decrease of β-catenin signaling in the brain.