Kindig C A, Poole D C
Department of Kinesiology and Department of Anatomy/Physiology, Kansas State University, Manhattan, Kansas, 66506-5602, USA.
Microvasc Res. 1998 May;55(3):249-59. doi: 10.1006/mvre.1998.2075.
Of all skeletal muscles examined in the rat, the spinotrapezius (S) and diaphragm (D) have the closest fiber-type composition. However, their oxidative capacities differ by two- to threefold. We have developed an intravital microscopy preparation to study diaphragm microcirculation in vivo. Using this preparation and the standard spinotrapezius model first described by S. D. Gray (1973, Microvasc. Res. 5, 395-400), we tested the hypothesis that pronounced microcirculatory differences would exist between these two muscles as a function of their disparate oxidative capacities. The lineal density of all capillaries in the spinotrapezius was 33.6 +/- 1.5 compared to 65.1 +/- 3.3 capillaries/mm in the diaphragm (P < 0.001). In the diaphragm compared with the spinotrapezius muscle, a significantly (P < 0.05) greater proportion of capillary countercurrent flow (D, 29 +/- 6% vs 8 +/- 6%) existed. Within both muscles, there was a similar proportion of capillaries supporting red blood cell (RBC) flow (S, 89 +/- 7% vs D, 92 +/- 2%). However, the diaphragm supported significantly (P < 0.001) greater intracapillary RBC velocities (D, 302 +/- 11 vs S, 226 +/- 9 micron/s) and fluxes (D, 33.4 +/- 1.1 vs S, 19.2 +/- 2.1 cells/s) compared with the spinotrapezius. Capillary "tube" hematocrit was greater (P = 0.01) in the diaphragm (0.32 +/- 0.02) than in the spinotrapezius (0.22 +/- 0.03) muscle. These data demonstrate that microcirculatory flow characteristics in resting muscle can be regulated independent of muscle fiber-type composition and may be related to muscle oxidative capacity.
在对大鼠检查的所有骨骼肌中，斜方肌（S）和膈肌（D）具有最接近的纤维类型组成。然而，它们的氧化能力相差两到三倍。我们开发了一种活体显微镜制备方法来研究体内膈肌微循环。使用这种制备方法和S.D.格雷（1973年，《微血管研究》5，395 - 400）首次描述的标准斜方肌模型，我们检验了这样一个假设，即由于这两块肌肉不同的氧化能力，它们之间会存在明显的微循环差异。斜方肌中所有毛细血管的线性密度为33.6±1.5，而膈肌中为65.1±3.3条毛细血管/毫米（P<0.001）。与斜方肌相比，膈肌中存在显著（P<0.05）更大比例的毛细血管逆流（膈肌为29±6%，斜方肌为8±6%）。在两块肌肉中，支持红细胞（RBC）流动的毛细血管比例相似（斜方肌为89±7%，膈肌为9%2±2%）。然而，与斜方肌相比，膈肌支持显著（P<0.001）更高的毛细血管内红细胞速度（膈肌为302±11，斜方肌为226±9微米/秒）和通量（膈肌为33.4±1.1，斜方肌为19.2±2.1个细胞/秒）。膈肌中毛细血管“管”血细胞比容（0.32±0.02）高于斜方肌（0.22±0.03）（P = 0.01）。这些数据表明，静息肌肉中的微循环流动特征可以独立于肌肉纤维类型组成进行调节，并可能与肌肉氧化能力有关。
