目的 探讨跑步训练对中老年雌性大鼠海马结构及海马结构内有髓神经纤维的影响。 方法 将10只14月龄的雌性SD大鼠随机分为跑步训练组和空白对照组,分别进行4个月的跑台训练和普通标准环境饲养。4个月后采用Morris水迷宫对两组大鼠的空间学习能力进行测试,然后运用透射电子显微镜和新的体视学方法对大鼠大脑海马结构及其内有髓神经纤维进行定量研究。 结果 与对照组相比,训练组老年雌性大鼠空间学习能力明显增强;海马结构总体积、海马结构内有髓神经纤维总长度显著增加,但海马结构内有髓神经纤维的总体积未见明显改变。海马结构内有髓神经纤维总长度分布图表明,训练组有髓神经纤维总长度的增加主要是由于细小直径的有髓神经纤维长度增加所致。 结论 跑步训练对中老年雌性大鼠的空间学习能力、海马结构及其内有髓神经纤维有明显的影响。
Objective To investigate the effects of exercise on the hippocampal formation and the myelinated nerve fibers in the hippocampal formation of middleaged rats. Methods Ten 14month female SD rats were randomly divided into exercise group and sedentary group.Rats in the exercise group were forced to run on a treadmill for 4 months. After 4 months, spatial learning capacity of two group rats was tested using the Morris water maze.Then, the hippocampal formation and the myelinated nerve fibers in the hippocampal formation were quantitatively estimated using transmission electronic microscopy and stereological techniques. Results Treadmill running enhanced the spatial learning capacity of the rats. The volume of hippocampal formation and the total length of the myelinated nerve fibers in the hippocampal formation were significantly increased after 4 months exercise.However,there was no significant difference in the total volume of the myelinated fibers in the hippocampal formation between the two groups.The absolute distributions of the total length of the myelinated fibers in the hippocampal formation of two groups indicated that the exerciseinduced increase of the total length of the myelinated nerve fibers in the hippocampal formation was mainly due to the increase of the myelinated fibers with small diameter. Conclusions Four months running exercise remarkably influence the spatial learning capacity,hippocampal formation and the myelinated fibers in the hippocampal formation of the middleaged famale SD rats. The present results reveal a potential mechanism for the fact that exercise might improve brain function.