Capillary Density of Skeletal Muscle in Dogs Exposed to Simulated Altitude 1
Capillary Density of Skeletal Muscle in Dogs Exposed to Simulated Altitude 1
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暴露于模拟海拔 1 的狗骨骼肌毛细血管密度
DOI：
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发表时间：
1975
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影响因子：
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通讯作者：
N. Banchero
中科院分区：
文献类型：
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作者：
N. Banchero
在人类和生活在慢性缺氧中的动物中，已经报道了许多解剖学和生理学上的变化。一般认为，这些变化在本质上是适应性的，它们有助于动物耐受低PO 2环境。可能这些特征或机制在人类和高海拔地区的动物中得到了最佳发展。然而，急性情况下，当一个低地动物暴露于低氧环境的研究，提供了机会，以确定如何快速发生这些变化，有时，提供了深入了解潜在的机制。Valdivia（1）发现，高海拔豚鼠（海拔4540米）骨骼肌中开放的毛细血管数量比海平面对照组多。他认为这是一个重要的适应机制，慢性缺氧，即使肌肉纤维的大小是大致相同的所有动物。最近，Cassin等人（2）发现，暴露于6,100 m 5周的大鼠骨骼肌中每单位表面积的毛细血管数量显著增加。然而，在低氧条件下毛细作用增加的证据及其在促进O2输送中的作用并不确定。此外，没有实验证据表明大型哺乳动物暴露于缺氧会导致外周组织的结构改变。材料和方法。三个成年杂种狗（两个男性和一个女性）本地丹佛（1610米PB 635毫米汞柱）进行了研究之前和之后的3周暴露于模拟海拔约4880米（环境压力435毫米汞柱），在此期间，他们接受食物和水随意。由于犬接受了在跑步机上跑步的训练，因此选择胸甲状肌进行研究，以尽量减少运动对骨骼肌的可能影响。
A number of anatomical and physiological changes have been reported in man and in animals living in chronic hypoxia. It is generally believed that these changes are adaptative in nature, and they help the animal tolerate a low Po2 environment. Possibly these features or mechanisms are optimally developed in man and in animals native to high altitude. However, the study of the acute situation, when a lowland animal is exposed to a low oxygen environment, offers the opportunity to ascertain how fast these changes occur, and, on occasion, provides insight into the underlying mechanisms. Valdivia (1) has found that high altitude guinea pigs (at 4540 m) have a greater number of open capillaries in skeletal muscle than sea level controls. He regarded this as an important adaptative mechanism to chronic hypoxia even though muscle fiber size was approximately the same in all animals. More recently Cassin et al. (2) showed that the number of capillaries per unit surface area in skeletal muscle of rats exposed to 6,100 m for 5 wk increased significantly. However, the evidence of an increased capillarity in hypoxic conditions and its role in facilitating O2 delivery is not conclusive. Furthermore, there is no experimental evidence that exposure of larger mammals to hypoxia results in structural alterations of peripheral tissues. Materials and Methods. Three adult mongrel dogs (two males and one female) native to Denver (1610 m PB 635 mmHg) were studied before and after a 3-wk exposure to a simulated altitude of about 4880 m (ambient pressure 435 mmHg) during which time they received food and water ad libitum. Because the dogs were trained to run on a treadmill, the sternothyroideous muscle was chosen for study in order to minimize the possible effects of exercise on the skeletal muscle.