Lashley Christopher J, Supik David A, Atkinson James T, Murphy Robert J, O'Hagan Kathleen P
Program in Biomedical Sciences, College of Health Sciences, Midwestern University, Downers Grove, Illinois, USA Department of Physiology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, Illinois, USA.
Program in Biomedical Sciences, College of Health Sciences, Midwestern University, Downers Grove, Illinois, USA.
Physiol Rep. 2015 Mar;3(3). doi: 10.14814/phy2.12337.
A major maternal adaptation in pregnancy is the large increase in uteroplacental blood flow that supplies the growing fetus with oxygen and nutrients. The impact of gestation on the dynamic uterine vasoconstrictor response to exercise in the rat, a common model for pathophysiological disorders in pregnancy remains unknown. We hypothesized that rats exhibit a robust uterine vasoconstrictor response to acute exercise that is attenuated in late pregnancy. Pregnant (P, N = 12) and nonpregnant (NP, N = 8) rats were instrumented chronically with a ultrasonic transit-time flowprobe and carotid arterial catheter to directly measure uterine artery blood flow (UtBF) and blood pressure (BP), respectively, at day 20 of gestation for 5 min of treadmill exercise (7 m/min; 6% grade). Preexercise UtBF [P, 2.1 (SD1.6) vs. NP, 0.5 (SD0.3) mL/min P < 0.01) and uterine artery conductance (UtC) [P, 2.1(SD1.7) vs. NP, 0.4 (SD0.2) mL/min × mmHg(-1) × 10(-2), P < 0.01] were higher in pregnant rats, whereas preexercise BP was lower in the pregnant rats [P, 111 (SD13) vs. NP, 126 (SD13) mmHg, P = 0.02]. Preexercise heart rate was similar [P, 457 (SD30) vs. NP, 454 (SD42), P = 0.3]. Exercise initiated rapid and sustained decreases in UtBF [Δ-47% (SD12)] and UtC [Δ-49% (SD12)] that were attenuated in the pregnant rats [UtBF, Δ-25% (SD20) and UtC, Δ-30% (SD20), P = 0.02]. The BP and heart rate responses to exercise were unaffected in late pregnancy (interaction term, P = 0.3). In rats, dynamic exercise induces a uterine vasoconstrictor response that is blunted during late gestation, a response that we observed previously in pregnant rabbits.
孕期母体的一个主要适应性变化是子宫胎盘血流量大幅增加，从而为生长中的胎儿提供氧气和营养物质。妊娠对大鼠运动时子宫动态血管收缩反应的影响尚不清楚，而大鼠是孕期病理生理紊乱的常用模型。我们假设，大鼠对急性运动表现出强烈的子宫血管收缩反应，而在妊娠晚期这种反应会减弱。在妊娠第20天，对12只怀孕（P）大鼠和8只未怀孕（NP）大鼠进行长期仪器植入，分别使用超声渡越时间血流探头和颈动脉导管，以直接测量跑步机运动5分钟（7米/分钟；坡度6%）期间的子宫动脉血流量（UtBF）和血压（BP）。运动前，怀孕大鼠的UtBF [P组，2.1（标准差1.6）与NP组，0.5（标准差0.3）毫升/分钟，P < 0.01]和子宫动脉传导率（UtC）[P组，2.1（标准差1.7）与NP组，0.4（标准差0.2）毫升/分钟×毫米汞柱-1×10-2，P < 0.01]较高，而怀孕大鼠运动前的血压较低[P组，111（标准差13）与NP组，126（标准差13）毫米汞柱，P = 0.02]。运动前心率相似[P组，457（标准差30）与NP组，454（标准差42），P = 0.3]。运动开始后，UtBF [变化-47%（标准差12）]和UtC [变化-49%（标准差12）]迅速且持续下降，而怀孕大鼠的下降幅度减弱[UtBF，变化-25%（标准差20）和UtC，变化-30%（标准差20），P = 0.02]。妊娠晚期，运动对血压和心率的反应未受影响（交互项，P = 0.3）。在大鼠中，动态运动诱导子宫血管收缩反应，而在妊娠晚期这种反应减弱，我们之前在怀孕兔子中也观察到了这种反应。
