Bailey J K, Kindig C A, Behnke B J, Musch T I, Schmid-Schoenbein G W, Poole D C
Departments of Kinesiology Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506-5602, USA.
Am J Physiol Heart Circ Physiol. 2000 Dec;279(6):H3131-7. doi: 10.1152/ajpheart.2000.279.6.H3131.
Intravital microscopy facilitates insights into muscle microcirculatory structural and functional control, provided that surgical exteriorization does not impact vascular function. We utilized a novel combination of phosphorescence quenching, microvascular oxygen pressure (microvascular PO(2)), and microsphere (blood flow) techniques to evaluate static and dynamic behavior within the exposed intact (I) and exteriorized (EX) rat spinotrapezius muscle. I and EX muscles were studied under control, metabolic blockade with 2,4-dinitrophenol (DNP), and electrically stimulated conditions with 1-Hz contractions, and across switches from 21 to 100% and 10% inspired O(2). Surgical preparation did not alter spinotrapezius muscle blood flow in either I or EX muscle. DNP elevated muscle blood flow approximately 120% (P < 0.05) in both I and EX muscles (P > 0.05 between I and EX). Contractions reduced microvascular PO(2) from 30.4 +/- 4.3 to 21.8 +/- 4.8 mmHg in I muscle and from 33.2 +/- 3.0 to 25.9 +/- 2.8 mmHg in EX muscles with no difference between I and EX. In each O(2) condition, there was no difference (each P > 0.05) in microvascular PO(2) between I and EX muscles (21% O(2): I = 37 +/- 1; EX = 36 +/- 1; 100%: I = 62 +/- 5; EX = 51 +/- 9; 10%: I = 20 +/- 1; EX = 17 +/- 2 mmHg). Similarly, the dynamic behavior of microvascular PO(2) to altered inspired O(2) was unaffected by the EX procedure [half-time (t(1/2)) to 100% O(2): I = 23 +/- 5; EX = 23 +/- 4; t(1/2) to 10%: I = 14 +/- 2; EX = 16 +/- 2 s, both P > 0.05]. These results demonstrate that the spinotrapezius muscle can be EX without significant alteration of microvascular integrity and responsiveness under the conditions assessed.
活体显微镜检查有助于深入了解肌肉微循环的结构和功能控制，前提是手术外置化不会影响血管功能。我们采用了磷光猝灭、微血管氧分压（微血管PO₂）和微球（血流量）技术的新型组合，以评估暴露的完整（I）和外置化（EX）大鼠斜方肌内的静态和动态行为。在对照、用2,4-二硝基苯酚（DNP）进行代谢阻断以及1 Hz收缩的电刺激条件下，以及在从21%到100%和10%吸入氧的转换过程中，对I和EX肌肉进行了研究。手术准备在I或EX肌肉中均未改变斜方肌的血流量。DNP使I和EX肌肉中的肌肉血流量均升高约120%（P < 0.05）（I和EX之间P > 0.05）。收缩使I肌肉中的微血管PO₂从30.4±4.3 mmHg降至21.8±4.8 mmHg，EX肌肉中的微血管PO₂从33.2±3.0 mmHg降至25.9±2.8 mmHg，I和EX之间无差异。在每种氧条件下，I和EX肌肉之间的微血管PO₂无差异（每种P > 0.05）（21%氧：I = 37±1；EX = 36±1；100%：I = 62±5；EX = 51±9；10%：I = 20±1；EX = 17±2 mmHg）。同样，微血管PO₂对吸入氧改变的动态行为不受EX程序的影响[到100%氧的半衰期（t₁/₂）：I = 23±5；EX = 23±4；到10%的t₁/₂：I = 14±2；EX = 16±2 s，两者P > 0.05]。这些结果表明，在评估的条件下，斜方肌可以进行外置化，而不会显著改变微血管的完整性和反应性。
