Richardson Troy E, Kindig Casey A, Musch Timothy I, Poole David C
Department of Kinesiology, Kansas State University, Manhattan, Kansas 66506-5802, USA.
J Appl Physiol (1985). 2003 Sep;95(3):1055-62. doi: 10.1152/japplphysiol.00308.2003. Epub 2003 May 9.
Chronic heart failure (CHF) reduces muscle blood flow at rest and during exercise and impairs muscle function. Using intravital microscopy techniques, we tested the hypothesis that the speed and amplitude of the capillary red blood cell (RBC) velocity (VRBC) and flux (FRBC) response to contractions would be reduced in CHF compared with control (C) spinotrapezius muscle. The proportion of capillaries supporting continuous RBC flow was less (P < 0.05) in CHF (0.66 +/- 0.04) compared with C (0.84 +/- 0.01) muscle at rest and was not significantly altered with contractions. At rest, VRBC (C, 270 +/- 62; CHF, 179 +/- 14 microm/s) and FRBC (C, 22.4 +/- 5.5 vs. CHF, 15.2 +/- 1.2 RBCs/s) were reduced (both P < 0.05) in CHF vs. C muscle. Contractions significantly (both P < 0.05) elevated VRBC (C, 428 +/- 47 vs. CHF, 222 +/- 15 microm/s) and FRBC (C, 44.3 +/- 5.5 vs. CHF, 24.0 +/- 1.2 RBCs/s) in C and CHF muscle; however, both remained significantly lower in CHF than C. The time to 50% of the final response was slowed (both P < 0.05) in CHF compared with C for both VRBC (C, 8 +/- 4; CHF, 56 +/- 11 s) and FRBC (C, 11 +/- 3; CHF, 65 +/- 11 s). Capillary hematocrit increased with contractions in C and CHF muscle but was not different (P > 0.05) between CHF and C. Thus CHF impairs diffusive and conductive O2 delivery across the rest-to-contractions transition in rat skeletal muscle, which may help explain the slowed O2 uptake on-kinetics manifested in CHF patients at exercise onset.
慢性心力衰竭（CHF）会减少静息和运动时的肌肉血流，并损害肌肉功能。我们使用活体显微镜技术，检验了以下假设：与对照（C）斜方肌相比，CHF时毛细血管红细胞（RBC）速度（VRBC）和通量（FRBC）对收缩反应的速度和幅度会降低。静息时，CHF（0.66±0.04）肌肉中支持连续RBC流动的毛细血管比例低于C（0.84±0.01）肌肉（P<0.05），且收缩后无显著变化。静息时，CHF肌肉的VRBC（C组，270±62；CHF组，179±14μm/s）和FRBC（C组，22.4±5.5对CHF组，15.2±1.2个RBC/s）均降低（均P<0.05）。收缩使C组和CHF组肌肉的VRBC（C组，428±47对CHF组，222±15μm/s）和FRBC（C组，44.3±5.5对CHF组，24.0±1.2个RBC/s）显著升高（均P<0.05）；然而，CHF组的两者仍显著低于C组。对于VRBC（C组，8±4；CHF组，56±11秒）和FRBC（C组，11±3；CHF组，(65\pm11)秒），CHF组达到最终反应50%的时间比C组减慢（均P<0.05）。C组和CHF组肌肉收缩时毛细血管血细胞比容增加，但CHF组和C组之间无差异（P>0.05）。因此，CHF会损害大鼠骨骼肌从静息到收缩转变过程中的扩散性和传导性氧输送，这可能有助于解释CHF患者运动开始时氧摄取动力学减慢的现象。
