大腦含有一個複雜的血管網，各腦區血流量和神經活性相關。隨著年齡增長，學習與記憶的功能逐漸下降。我們假設這可能與腦血管功能下降有關。而跑步運動已知能增加神經新生與記憶功能，以及提升血管內皮細胞功能與增加腦血管密度。但是，目前針對老化與運動對腦血管之研究，多集中在探討大腦皮質與海馬迴腦區，對其他腦區的影響仍不清楚。因此，本研究目的有二: (一) 定量老化對各腦區腦血管數量之影響，(二)探討跑步運動對各腦區腦血管之影響。我們把不同年紀的小鼠，施以六周跑步機運動訓練之後，再對14個腦區血管之面積、密度、和直徑進行測量。實驗結果顯示，小鼠腦血管之總面積比例，會隨老化有不同變化，而且具有腦區的差異。在小鼠的伏隔核 (accumbens nucleus)、海馬迴CA1 (cornus ammonis 1)、內嗅皮質 (entorhinal cortex) 與梨狀皮質 (piriform cortex) 這四個腦區中，腦血管總面積隨著老化而逐漸下降；而運動皮質 (motor cortex) 直到老年才有顯著影響。嗅球 (olfactory bulb)、中腦 (midbrain)、小腦 (cerebellum)、感覺皮質 (sensory cortex)、紋狀體 (striatum)、海馬迴CA3、齒狀迴 (dentate gyrus)、丘腦 (thalamus) 以及下丘腦 (hypothalamus) 之腦血管面積，則沒有隨年紀而有明顯變化。有趣的是，大部分中年小鼠的腦血管密度 (單位面積下之血管數量) 皆有增加之趨勢，但是只有在伏隔核這個腦區顯著上升。至於大部分腦區之血管直徑，並不會隨年紀而有顯著改變。六周跑步機運動會增加14個腦區中之8個腦區的腦血管總面積，包括:伏隔核、海馬迴CA1、內嗅皮質、運動皮質、梨狀皮質、嗅球、中腦、感覺皮質。同時，跑步運動會抑制中年時血管密度之上升；對腦血管之直徑影響不大。本研究得到以下結論:有些小鼠腦區之腦血管總面積會隨著老化而逐漸下降，反之，這些腦區之腦血管密度會在中年有上升的情形。六周的中度跑步運動，會抑制老化所導致的腦血管改變，而回復到較年輕的狀態。

Brain contains a complex vascular network which tightly regulates the activity of neural networks. Aging is known to associate with impaired brain function. We hypothesize it is related to a dysfunction of cerebrovascular network. On the other hand, running exercise is known to enhance neurogenesis and cognitive function, as well as increase endothelial function and capillary density in certain brain regions. However, most studies investigated the effect of aging or exercise on cerebrovascular network focusing only on a few brain regions (e.g. cortex and hippocampus) and leaving the majority of brain unexamined. Therefore, the objectives of this study are 1) to characterize the effect of aging on the cerebral vasculature in various brain regions; 2) to study the effect of running exercise on the cerebral vasculature. Mice of different ages were forced to run on treadmill for six weeks and their cerebral vessel area (% area in a designated region), density, and diameter were measured in 14 brain regions. Our results showed that cerebral vessel area changes with age in a brain region-specific manner. Among them, the % area of the accumbens nucleus, hippocampal CA1, entorhinal cortex and piriform cortex decreased with age, while the cerebral vessel area of motor cortex did not change until old age. No change was evident in the cerebral vessel area of the olfactory bulb, midbrain, cerebellum, sensory cortex, striatum, CA3, dentate gyrus, thalamus and hypothalamus. Interestingly, when compared to young age, a trend of higher capillary density (the number of capillary cross the grid) in middle age was evident in most brain regions. We did not observe a change in the diameter of capillary in most brain regions. Six weeks of treadmill running increased the cerebral vessel areas in 8 of 14 regions, including accumbens nucleus, CA1, entorhinal cortex, motor cortex, piriform cortex, olfactory bulb, midbrain and sensory cortex. At the mean times, treadmill running reduced the effect of middle age-associated increases of the capillary density, but had little effect on capillary diameter. In conclusion, the cerebral vessel areas in certain brain regions are reduced as age increased; whereas, the cerebral vessel densities are increased, especially in the middle-age, of the same regions. Six weeks of running exercise reverse such changes in older ages and maintain the qualities of cerebral vasculature as they were in younger age.

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