Mooradian A D, McCuskey R S
Department of Internal Medicine, St. Louis University School of Medicine, MO 63104.
Mech Ageing Dev. 1992 Jul 15;64(3):247-54. doi: 10.1016/0047-6374(92)90082-o.
To determine if hemodynamic changes in cerebral microvessels could contribute to the age-related changes in the blood-brain barrier (BBB) function, the cerebral microvessels of male Fischer 344 rats at different ages were studied using intravital fluorescence microscopy. Aging in rats was associated with significant arteriovenous shunting in the cerebral microvessels without alterations in blood flow characteristics or changes in vascular permeability to FITC dextran (150 kDa). The basal diameter of terminal arterioles examined in 24- to 27-month-old (aged) rats (28.6 +/- 2.8 microns) was not different from that in 12- to 15-month-old (intermediate age) rats (32.5 +/- 2.5 microns) or in 3- to 6-month-old (young) rats (28.6 +/- 3.0 microns). At 3 s following addition of 5% BaCl2 there was 23.3 +/- 3.47% constriction of arterioles in young rats and 14.8 +/- 5.16% constriction in intermediate age rats, but only a 3.43 +/- 5.69% change in aged rats (P less than 0.03). This initial brief constriction phase was followed by a dilatory response which was similar in all age groups. One minute following suffusion with artificial cerebrospinal fluid, the arteriolar diameter essentially returned to baseline in all rats examined. It is concluded that aging in rats is associated with alterations in cerebral microvascular reactivity in vivo along with arteriovenous shunting. These changes may contribute to age-related alterations in the BBB function.
为了确定脑微血管中的血流动力学变化是否可能导致血脑屏障（BBB）功能的年龄相关变化，使用活体荧光显微镜对不同年龄雄性Fischer 344大鼠的脑微血管进行了研究。大鼠衰老与脑微血管中显著的动静脉分流有关，而血流特征无改变，对异硫氰酸荧光素葡聚糖（150 kDa）的血管通透性也无变化。在24至27月龄（老年）大鼠中检测的终末小动脉基底直径（28.6±2.8微米）与12至15月龄（中年）大鼠（32.5±2.5微米）或3至6月龄（年轻）大鼠（28.6±3.0微米）的相比无差异。添加5%氯化钡3秒后，年轻大鼠的小动脉收缩23.3±3.47%，中年大鼠收缩14.8±5.16%，而老年大鼠仅变化3.43±5.69%（P<0.03）。这个最初的短暂收缩阶段之后是扩张反应，所有年龄组的反应相似。用人工脑脊液灌注1分钟后，所有检查的大鼠中小动脉直径基本恢复到基线。结论是，大鼠衰老与体内脑微血管反应性改变以及动静脉分流有关。这些变化可能导致血脑屏障功能的年龄相关改变。
