我们在国际上首次运用三维定量的体视学方法发现：①老年大脑白质萎缩主要是由于有髓神经纤维改变所致；②白质内毛细血管存在显著性老年改变；③跑步训练对老年大脑白质及白质内有髓神经纤维具有积极的保护作用。老年大脑白质的血供显著性下降，而髓鞘形成细胞（少突胶质细胞）对缺血缺氧很敏感。跑步训练是否是通过改善老年大脑白质的血供而实现对老年大脑白质的保护作用呢？跑步训练对老年大脑白质毛细血管的作用及机制，以及这些作用与跑步训练对老年大脑白质及白质内有髓神经纤维作用的关系，国内、外尚未见研究报道。而回答这些问题对认识跑步训练保护老年大脑白质的机制具有重要的科学意义。因此，我们拟运用行为学、免疫组织化学、电镜技术、体视学和分子生物学等方法研究跑步训练对老年大脑白质毛细血管的作用及机制，以期进一步认识跑步训练对老年大脑功能作用的结构和分子生物学基础，从而为寻找缓解大脑衰老进程的各种药物和行为学手段提供科学依据。

Using the three-dimensional stereological methods, we have for the first time in the world obtained the following findings. 1. The age-related atrophy of white matter was mainly due to the changes of the myelinated fibers in the aged white matter. 2. There was significant decline in the capillaries of aged white matter. 3. There were significant protective effects of running exercise on the aged white matter and the myelinated fibers of aged white matter. The blood supply of aged white matter was significantly decreased and the myelin-formed cells, oligodendrocytes, were very sensitive to the deficiency in blood supply and oxygen. Whether did running exercise protects the aged white matter through the improvement of the blood supply in aged white matter? Until now, there have been no studies in the world regarding the effects of running exercise on the capillaries of aged white matter and the mechanisms of these effects, the relationship between the effects of running exercise on the capillaries in aged white matter and the effects of running exercise on the aged white matter and the myelinated fibers in aged white matter. To answer these questions has very important value for understanding the mechanisms of the protective effects of running exercise on aged white matter. Therefore, in the current project, we plan to use behavioral methods, immunohistochemical methods, transmission electron microscope techniques, stereological methods and molecular biological methods to study the effects of running exercise on the capillaries in aged white matter and the mechanisms of these effects. The results obtained in the present project will be very helpful for further understanding the structural and molecular bases of the effects of running exercise on aged brain, which will provide very important scientific bases for exploring the drugs and behavioral means to delay the aging process of brain.