自然衰老小鼠室管膜下区神经干细胞增龄性改变

目的 探讨自然衰老小鼠室管膜下区（SVZ）神经干细胞（NSCs）在衰老过程中生物学特点的改变。 方法 2月龄、28月龄小鼠，各10只，体外分离、培养、鉴定NSCs，5-溴-2-脱氧尿苷（BrdU）染色比较两组细胞的增殖水平；β-半乳糖苷酶（SA-β-Gal）染色检测细胞衰老水平；细胞内活性氧（ROS）试剂盒检测细胞ROS表达水平；Western blotting 检测细胞周期蛋白D1（cyclin D1）、p16及p19蛋白表达水平；体内用巢蛋白（Nestin）/性别决定基因高迁移率组蛋白-2（Sox2）检测两组小鼠SVZ区厚度的差异。 结果 年轻、年老小鼠的神经干细胞能表达Nestin及Sox2，符合神经干细胞的表达特性。与年轻小鼠相比，年老小鼠神经干细胞的BrdU阳性细胞比例显著下降，SA-β-Gal阳性细胞百分比显著升高，细胞活性氧水平显著升高，SVZ区厚度明显变薄，差异具有统计学意义（P<0.05）。在分子水平上表现为cyclin D1蛋白表达水平明显下降，p16、p19蛋白表达水平显著升高。 结论 年老小鼠NSCs出现增龄性变化，这些变化可能在大脑衰老中起重要作用。

Age-related changes of neural stem cells from the subventricular zone of aged mice

Objective To investigate the biological changes of neural stem cells (NSCs) of mice from subventricular zone (SVZ) during aging. Methods NSCs were isolated, cultured and identified from 2 month (young) and 28 month (aged) old mice respectively, with 10 mice in each group. The proliferation ability of NSCs was determined by BrdU staining; cellular senescence was detected by senescence-associated-β-galactosidase (SA-β-gal) staining; ROS level was determined by ROS kit; expression of cyclin D1, p16, p19 protein in NSCs was tested by Western blotting. The thickness of SVZ between the two groups was detected by nestin/Sox2 staining.Results Positive expressions of neural stem cell marker nestin and Sox2 were identified in NSCs of the young and the aged mice. Aged NSCs exhibited a decreased percentage of BrdU positive cells, increased SA-β-gal activity, elevated intracellular reactive oxygen species level, decreased pool size in the SVZ zone, and there were significant differences (P<0.05). Additionally, at the molecular level, aged NSCs exhibited a decrease of cyclin D1 and an increase of p16 and p19.Conclusion Aged NSCs demonstrate aging changes which may play an important role in brain aging.