自主运动对小鼠神经干细胞增殖及相关基因表达的影响

Effects of Voluntary Exercise on Neural Stem Cell Proliferation and Related Genes of Mice

实验选用24只5周龄的C57BL/6雄性小鼠,随机分为运动组12只(R组)和对照组12只(C组),其中R组进行8周自主跑轮运动。第5周开始,随机从两组小鼠中各抽取6只,共12只进行连续1周的Brd U注射。8周运动结束后,对12只未注射Brd U的小鼠进行断颈,取双侧海马,放入-80℃超低温冰箱保存,待检测生化指标。对注射Brd U的12只小鼠进行免疫组化染色预处理,随后进行Brd U单标免疫荧光染色,从形态学角度观察神经干细胞增殖情况并计数。对未注射小鼠进行RT-PCR检测其NGF、Jagged-1、PS1、Hes1、Hes5、Hes6的m RNA水平;结果:8周自主运动后小鼠海马神经干细胞数量显著增加(p<0.01),Notch信号通路中配体Jagged-1、靶基因Hes1的m RNA表达水平显著升高(p<0.01)。神经生长因子NGF的m RNA表达量显著升高(p<0.01)。NGF与配体Jagged-1、靶基因Hes1呈高度相关性(p<0.01)。结论:8周自主跑轮运动促进小鼠海马神经干细胞增殖,可能和Notch信号通路的激活有关。此外,8周运动促使NGF的表达量升高,提示NGF与Notch信号通路可能存在交互作用,可以共同调节Notch信号通路下游靶基因的变化,从而影响神经干细胞的增殖分化。

[Objective and Methods] 24 male mice bomed 5 weeks （C57BL/6） are randomly divided into running group （n=12） and control group （n=12）, while the running group do voluntary wheel running for 8 weeks. Since the 5th week, 12 mice（ each 6 from the two groups） were datelabelled with BrdU for one week, at the. The 12 mice without BrdU datelabelled were killed on the last day after 8 weeks exercise, bilateral hippocampal of them were taken out to be kept in - 80 ℃ cryogenic refrigerator, the mRNA levels of NGF, Jagged-1 mRNA, PS1, Hes1, Hes-5, Hes6 of them were tesetd by RT-PCR method. The 12 mice with BrdU datelabelled were pretreated by immunohistochemical method, then were stained with the method of BrdU single standard immunofiuorescence. From the perspective of morphological, neural stem cells proliferation of them were observed and counted. [Results] After 8 weeks of autonomous movement, number of hippocampal neural stem cells increased significantly （p 〈 0.01）, the ligand Jagged-1 in Notch signaling pathway, mRNA expression level of Hesl target gene were significantly increased （13 〈 0.01）. the amount of mRNA expression of nerve growth factor NGF significantly increased （p 〈 0.01）.There is highly correlation among model NGF, ligand Jaged-I and target genes Hesl （p 〈 0.01）.[Conclusion] 8 weeks voluntary exercise can obviously increase BrdU＋ labeled neural stem cells in hippocampal region; Voluntary exercise significantly increased Jagged-1 and Hes 1 gene expression, illustrating that voluntary exercise activate the Notch signaling pathway, which impact the hippocampal neural stem cell proliferation; NGF could directly regulate Notch downstream target genes expressions, which participate in the regulation of neural stem cell proliferation, and affect the ability of learning and memory.