Comparison of hyper- and microgravity on rat muscle, organ weights and selected plasma constituents.
Comparison of hyper- and microgravity on rat muscle, organ weights and selected plasma constituents.
复制标题
超重力和微重力对大鼠肌肉、器官重量和选定血浆成分的比较。
DOI：
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发表时间：
1998
影响因子：
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通讯作者：
C. Wade
中科院分区：
文献类型：
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作者：
M. Vasques;C. Lang;R. Grindeland;R. Roy;N. Daunton;A. Bigbee;C. Wade
背景
离心法已被认为是一种可能的对策，以解决与慢性卸载相关的骨骼肌、器官、激素和血浆化学适应(例如，在航天飞行期间)。
假设
我们的假设是，从零重力到超重力，会有一系列的生理和形态反应。
方法
成年雄性大鼠在2G下连续离心14d，测定四肢肌肉和器官的重量，并将其血浆成分水平与14d航天飞行大鼠(Cosmos 2044)的相同测量结果进行比较。
结果
离心机大鼠的平均体重没有变化，而年龄匹配的对照组增长了21%。离心机组大鼠的肌肉蛋白质含量较少；主要是后肢缓慢的肌肉的绝对重量保持不变，几乎所有研究肌肉的相对重量(相对于体重和与对照组的百分比差异)都大于对照组。相比之下，太空飞行导致了大多数后肢伸肌的相对重量减少，但不是屈肌。一般来说，与对照组相比，离心机组大鼠的相对器官重量增加。除了睾丸重量降低外，飞行大鼠的相对器官重量与对照组相似。飞行后血浆甲状腺激素和睾酮水平显著降低，而离心后只有甲状腺激素水平下降。离心导致大多数其他血浆化学指标的下降，而飞行大鼠的这些指标没有变化或上升。
讨论
这些数据表明，对微重力和超重力的生理反应往往是相反的，这表明总体上存在从微重力到1G再到超重力的一系列生理和形态效应。这些数据进一步表明，对处于微重力环境中的动物施加超重力条件可能对将某些生理系统维持在或接近控制水平具有有益的效果。
BACKGROUND
Centrifugation has been proposed to be one possible countermeasure for the skeletal muscle, organ, hormonal, and plasma chemistry adaptations associated with chronic unloading (e.g., during spaceflight).
HYPOTHESIS
Our hypothesis was that there would be a continuum of physiological and morphological responses from zero gravity to hypergravity.
METHODS
Adult male rats were centrifuged continuously at 2G for 14 d and the weights of limb muscles and organs, and the levels of plasma constituents were compared with the same measurements from rats flown on a 14-d spaceflight (Cosmos 2044).
RESULTS
Mean body weights of centrifuge rats did not change, whereas age-matched controls grew 21%. There was a sparing of muscle protein in the centrifuge rats; the absolute weights of predominantly slow muscles in the hindlimb were maintained and the relative weights (expressed relative to body weight and as a percent difference from control) of almost all muscles studied were larger than control. In contrast, spaceflight resulted in a decrease in the relative weights of most extensor, but not flexor, hindlimb muscles studied. Relative organ weights, in general, were elevated in centrifuge rats compared with control rats. Relative organ weights in flight rats were similar to control, except for a decrease in testes weight. Plasma thyroxine and testosterone levels were significantly reduced following flight, whereas only thyroxine was decreased after centrifugation. Centrifugation resulted in a decrease in most other plasma chemistry measurements, whereas flight rats showed no change or an elevation in these measures.
DISCUSSION
These data indicate that the physiological responses to micro- and hypergravity are often in the opposite direction, suggesting that in general there is a continuum of physiological and morphological effects from microgravity to 1G to hypergravity. These data further suggest that the imposition of hypergravity conditions on animals that are in a microgravity environment may have a beneficial effect in maintaining some physiological systems at or near control levels.