De Abreu Steven, Amirova Liubov, Murphy Ronan, Wallace Robert, Twomey Laura, Gauquelin-Koch Guillemette, Raverot Veronique, Larcher Françoise, Custaud Marc-Antoine, Navasiolava Nastassia
Mitovasc, UMR Institut National de la Santé et de la Recherche Médicale 1083, Centre National de la Recherche Scientifique 6015, Université d'Angers, Angers, France.
Russian Federation State Research Center, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia.
Front Physiol. 2017 Oct 13;8:799. doi: 10.3389/fphys.2017.00799. eCollection 2017.
Dry immersion (DI) is a Russian-developed, ground-based model to study the physiological effects of microgravity. It accurately reproduces environmental conditions of weightlessness, such as enhanced physical inactivity, suppression of hydrostatic pressure and supportlessness. to study the integrative physiological responses to a 3-day strict DI protocol in 12 healthy men, and to assess the extent of multi-system deconditioning. We recorded general clinical data, biological data and evaluated body fluid changes. Cardiovascular deconditioning was evaluated using orthostatic tolerance tests (Lower Body Negative Pressure + tilt and progressive tilt). Metabolic state was tested with oral glucose tolerance test. Muscular deconditioning was assessed via muscle tone measurement. Orthostatic tolerance time dropped from 27 ± 1 to 9 ± 2 min after DI. Significant impairment in glucose tolerance was observed. Net insulin response increased by 72 ± 23% on the third day of DI compared to baseline. Global leg muscle tone was approximately 10% reduced under immersion. Day-night changes in temperature, heart rate and blood pressure were preserved on the third day of DI. Day-night variations of urinary K diminished, beginning at the second day of immersion, while 24-h K excretion remained stable throughout. Urinary cortisol and melatonin metabolite increased with DI, although within normal limits. A positive correlation was observed between lumbar pain intensity, estimated on the second day of DI, and mean 24-h urinary cortisol under DI. , DI represents an accurate and rapid model of gravitational deconditioning. The extent of glucose tolerance impairment may be linked to constant enhanced muscle inactivity. Muscle tone reduction may reflect the reaction of postural muscles to withdrawal of support. Relatively modest increases in cortisol suggest that DI induces a moderate stress effect. , this advanced ground-based model is extremely suited to test countermeasures for microgravity-induced deconditioning and physical inactivity-related pathologies.
干浸（DI）是一种由俄罗斯研发的地面模型，用于研究微重力的生理效应。它能精确再现失重的环境条件，如身体活动减少、静水压力抑制和无支撑状态。本研究旨在探讨12名健康男性在3天严格干浸方案下的综合生理反应，并评估多系统失适应的程度。我们记录了一般临床数据、生物学数据并评估了体液变化。使用直立耐力试验（下体负压+倾斜和渐进倾斜）评估心血管失适应情况。通过口服葡萄糖耐量试验测试代谢状态。通过测量肌肉张力评估肌肉失适应情况。干浸后直立耐力时间从27±1分钟降至9±2分钟。观察到葡萄糖耐量有显著损害。与基线相比，干浸第三天净胰岛素反应增加了72±23%。浸入状态下整体腿部肌肉张力降低了约10%。干浸第三天体温、心率和血压的昼夜变化得以保留。从浸入第二天开始，尿钾的昼夜变化减小，而24小时钾排泄在整个过程中保持稳定。尿皮质醇和褪黑素代谢产物随干浸增加，尽管仍在正常范围内。在干浸第二天估计的腰痛强度与干浸下平均24小时尿皮质醇之间观察到正相关。总之，干浸代表了一种准确且快速的重力失适应模型。葡萄糖耐量损害的程度可能与持续增强的肌肉不活动有关。肌肉张力降低可能反映了姿势肌肉对失去支撑的反应。皮质醇相对适度的增加表明干浸会诱发中度应激效应。因此，这种先进的地面模型非常适合测试针对微重力诱导的失适应和与身体不活动相关疾病的对策。
