短期丰富生存环境增加中老年雄性大鼠海马结构内有髓神经纤维的总长度

目的探讨短期丰富生存环境干预对正常中老年雄性大鼠海马结构及海马内有髓神经纤维的影响。方法将20只14月龄的雄性SD大鼠随机分为丰富生存环境组与空白对照组,前者在丰富生存环境条件下饲养4个月,后者在普通环境中饲养4个月后,采用Morris水迷宫测试两组大鼠的空间学习能力;运用透射电子显微镜和体视学方法对两组大鼠海马结构及海马内有髓神经纤维进行定量研究。结果丰富生存环境组大鼠空间学习能力与空白对照组之间不存在显著性差异;丰富生存环境组与空白对照组相比较,海马结构总体积两组间无显著性差异。丰富生存环境组海马结构内有髓神经纤维的总体积、有髓神经纤维总长度、有髓神经纤维平均直径显著增加。结论短期丰富生存环境干预对14月龄雄性大鼠海马有髓神经纤维具有显著性影响。这一研究结果为将来寻找延缓大脑衰老进程的行为学手段提供了重要的理论依据。

Short-term enriched environment increases the total length of the myelinated nerve fibers in the hippocampal formation of mid-aged male rats

Objective To investigate the effects of short-term enriched environment on the hippocampal formation and the myelinated fibers in the hippocampal formation of mid-aged male rats. Methods Twenty 14-month old male SD rats were randomly divided into enriched group and standard group. Enriched rats were reared in enriched environment and standard rats were reared in standard environment for 4 months. Then, the spatial learning capacity of enriched rats and standard rats was tested with the Morris water maze. After the Morris water maze test, the total volume of the hippocampal formation and the myelinated nerve fibers in the hippocampal formation were quantitatively estimated with transmission electronic microscopy technique and stereological methods. Results There was not significant difference in the spatial learning capacity between enriched group and standard group. The total volume of the hippocampal formation of enriched rats was not significantly increased by 4.6% when compared with that of standard rats. The total volume, total length and mean diameter of the myelinated nerve fibers in the hippocampal formation of enriched rats were significantly increased when compared with those of standard rats. Conclusions Four-months enriched environment significantly affected the myelinated fibers in the hippocampal formation of mid-aged male SD rats. The present results might provide an important theoretical basis for searching the ethology strategy to delay the progress of brain aging in the future.