跑步锻炼对APP/PS1双转基因AD模型小鼠大脑白质及白质内有髓神经纤维的作用

Effects of running exercise on the white matter and the myelinated fibers in the white matter of the APP/PS1 double transgenic mouse model of Alzheimer’s disease

摘要:

目的：运用新的体视学方法定量研究跑步锻炼对APP/PS1双转基因模型小鼠行为学、大脑白质及白质内有髓神经纤维的作用。方法：将6月龄雌性APP/PS1双转基因阿尔兹海默病（Alzheimer’s disease，AD）模型小鼠分为对照组（n=7）和跑步组（n=12），跑步组给予4个月的跑步锻炼干预。跑步后运用Morris水迷宫实验检测小鼠的空间学习和记忆能力；用精确的三维体视学方法来定量测定小鼠白质总体积、白质内有髓神经纤维总长度，白质内有髓纤维、髓鞘和轴突的总体积。结果：经过4个月的跑步锻炼后，跑步组小鼠的定位航行实验显示其平均逃避潜伏期明显短于对照组（P=0.000），空间探索实验表明跑步组穿台次数和平台所在象限时间百分比明显大于对照组（P=0.000，P=0.009）。与对照组小鼠比较，跑步组小鼠白质总体积、白质内有髓纤维总体积和轴突的总体积明显增加（P=0.026，P=0.042，P=0.027），而白质内有髓神经纤维总长度和有髓神经纤维髓鞘总体积差异无统计学意义（P=0.259，P=0.901）。结论：跑步锻炼对白质体积和有髓神经纤维的作用可能是跑步锻炼延缓AD学习和记忆力下降的重要结构基础之一。

Abstract:

Objective：To investigate the effects of running exercise on the white matter and the myelinated fibers in the white matter of the APP/PS1 double transgenic mouse. Methods：Six-month-old female APP/PS1 transgenic mice were divided into the control group（n=7） and the running group（n=12）. The running group ran for four months. Seven mice were randomly selected from each group. After running exercise，Morris water maze test was used to detect the spatial learning and memory abilities of the mice in both groups. The white matter volume，the total length and total volume of the myelinated fibers in the white matter，the total volume of the myelin sheaths and the total volume of the axons in the white matter were investigated with the accurate three-dimensional quantitative stere－ological methods. Results：After four-month running exercise，the mean escape latency of positioning navigation test in the run－ning group was significantly shortened when compared with that in contol group（P=0.000），while the target zone frequency and the percentage of time in target quadrant of the running group in spatial probe test were significantly increased when compared with those in control group（P=0.000，P=0.009）. When compared with those in control group，the white matter volume，the total volume of the myelinated fibers and the total volume of the axons in the white matter were significantly increased in the running group（P=0.026，P=0.042，P=0.027）. The total length of myelinated fibers and the total volume of myelinated sheath in the white matter were not sta－tistically different between the two groups（P=0.259，P=0.901）. Conclusion：The effects of running exercise on the white matter and the myelinated fibers in the white matter might be an important structural basis for understanding the mechanism for the fact that running exercise could delay Alzheimer’s disease progress.