航天员应付失重的方法

为了克服失重对人体的不利影响,保证航天员的健康和飞行中的工作效率,在40多年的载人航天实践中,航天医学研究者们始终没有停止过对失重生理及对抗措施的研究。通过不断地深入研究和大量的航天飞行实践,他们摸索出一套应付失重的“招数”。只要航天员在航天飞行中能够运用这套制胜法宝,就能够最大限度地降低失重对其身体健康的影响,胜利完成航天飞行任务。体育锻炼适量的体育运动不但能够锻炼肌肉和骨骼,同时还可以增加人体的耗氧量,从而增强心血管系统的调节能力。因此,航天员都要进行体育锻炼,以防止失重导致的心血管功能失调、骨丢失和肌…     

转化生长因子-β及其在微重力下生物效应的研究进展

失重对于人体的损伤及相应的保护措施一直是航天医学研究的热点问题.转化生长因子-β(TGF-B)作为刺激细胞增殖分化、调节细胞外间质(ECM)的合成降解、调控其他细胞因子功能的重要枢纽,在失重肺促纤维化样改变、骨丢失、伤口修复等过程中发挥重要作用.失重和模拟失重条件下TGF-B及其下游信号在各个组织中的转录表达水平是不同...     

运动性肌肉疲劳影响预期姿势调节的研究进展

肌肉活检作为一项有效的科学研究技术，在骨骼肌失重防护中发挥重要作用。该技术以能直接获取肌肉组织，从微观层面进行实验研究的特点在国外航天医学领域中得到广泛应用，但在我国航天医学领域中的应用尚属空白。该文综合分析国内外利用肌肉活检技术的相关研究，对肌肉活检技术在骨骼肌失重防护中的应用进行全面阐述，并提出将该技术引入我国航天医学领域的研究中，旨在为我国载人航天利用肌肉活检技术研究骨骼肌失重防护机制提供理论指导与依据。     

中药对抗航天飞行中失重所致生理紊乱的实验研究进展

在我国航天综合生命保障措施中,应用复方中药对抗失重引发的生理效应日益受到重视.大量研究表明,中药有助于调节失重或模拟失重条件下机体的神经内分泌免疫功能、改善心血管功能、对抗骨质丢失和肌肉萎缩及其他生理功能异常.本文对相关实验研究进展进行综述和展望.     

中药对抗航天飞行中失重所致生理紊乱的实验研究进展（英文）

在我国航天综合生命保障措施中,应用复方中药对抗失重引发的生理效应日益受到重视。大量研究表明,中药有助于调节失重或模拟失重条件下机体的神经内分泌免疫功能、改善心血管功能、对抗骨质丢失和肌肉萎缩及其他生理功能异常。本文对相关实验研究进展进行综述和展望。     

中药和低频磁场对模拟失重骨丢失的防护作用

失重骨丢失对航天员的身体健康和工作效率会产生不利影响,因此失重骨丢失的防护问题是航天医学领域的重要研究课题。为了建立有效的失重骨丢失对抗措施,我们开展了“中药和低频磁场对模拟失重大鼠骨丢失防护作用”的研究。本研究选用SD 雄性成年大鼠为实验动物,采用尾部悬吊模拟失重动物模型,以中药和磁场刺激为骨丢失对抗措施。中药以饮水方式供给,磁场刺激的使用频率为15Hz,磁感应强度为5.5-11mT,模拟失重时间为21天。观察指标及方法:胫骨形成率采用萤光标记显微测量法,股骨平均密度采用排水称重法,骨矿物盐含量采用软x 线拍片密度测量法,股骨力学特征采用三点弯曲实验取得相应的力学参数。骨钙素含量测定采用放射免疫法。实验结果表明,中药和低频磁场刺激可使悬吊大鼠股骨平均密度增加;可促进悬吊大鼠胫骨骨形成,使胫骨形成率比悬吊对照组增加2倍左右;中药和低频磁场刺激可增加悬吊大鼠股骨力学强度,股骨硬度和最大载荷的增加幅度范围在16%～47%之间;中药和低频磁场可使悬吊大鼠后肢骨矿含量增加,中药组增加19.2mg/cm~3,低频磁场组增加65.1mg/cm~3,中药+磁场组增加96.5mg/cm~3,说明中药和磁场两种防护措施间存在协同效应;同时也观察到中药和磁场可使悬吊大鼠跟骨和血清中骨钙素含量增加,它们可能具有促进成骨细胞生理功能的作用。本研究结果表明,中药和低频磁场刺激对悬吊模拟失重大鼠骨丢失都具有明显的防护作用,而且两种对抗措施之间有明显的协同效应。由此可以认为中药和低频磁场骨丢失对抗措施在航天中有广泛的应用前景。     

长期空间站驻留后航天员返回地面时着陆冲击耐力分析

在长期空间站驻留期间,人体生理机能会发生一系列的改变,机体最终会适应这种失重环境。但是流体静压消失使机体的有效循环血量减少,并且心血管系统处于一种低动力状态,重力消失导致的骨丢失和肌肉萎缩将持续进行。在航天任务结束后返回地面的过程中,航天员会再次受到着陆冲击过载的作用,此时机体尚未完成对重力的再适应过程,因此其耐受性会比航天飞行前有所降低。但到目前为止,其降低的程度还不完全清楚。本文在总结飞船着陆冲击特点的基础上,综合分析人体着陆冲击耐力及其影响因素,以及长期空间站驻留机体的变化对着陆冲击耐力的影响,并借鉴NASA3001标准,分析了长期空间站驻留后航天员着陆冲击耐力下降的程度。     

载人航天活动中对抗失重影响的措施及其效果

为了给我国筛选并制定科学有效的失重对抗措施方案提供有价值的参考资料,本文列举了航天活动中已经采用和可能应用的对抗失重影响的措施,对已经使用的对抗措施效果进行评估,对潜在的新对抗措施进行可行性分析。综合分析表明:下体负压与有氧运动锻炼在对抗心血管系统脱适应方面具有显著作用;有氧运动与阻力锻炼是对抗骨丢失、抗重力骨骼肌萎缩与平衡系统机能改变的主要措施;采用药物防治空间运动病具有明显的效果。然而,这些对抗措施均不具备全面对抗失重影响的作用。目前一般采用多种对抗措施配套使用,不仅仪器设备多,且花费较长时间进行锻炼。另外,多种对抗措施需要科学配套,否则难以达到预期的对抗效果。人工重力将成为具有全面对抗失重对航天员影响的首选措施,应尽快对其实施方案、人体各系统所需的合适强度-持续时间关系、空间实施过程中存在的潜在副作用等进行详细的观测与研究,以期早日在航天活动中使用,并对其防护效果进行综合评估。     

肌肉活检在骨骼肌失重防护中的应用进展

肌肉活检技术以能直接获取肌肉组织,从微观层面进行实验研究的特点在国外航天医学领域中得到广泛应用,但在我国航天医学领域中的应用尚属空白。综合分析了国内外利用肌肉活检技术的相关研究,对肌肉活检技术在骨骼肌失重防护中的应用进行全面阐述,包括肌肉活检在骨骼肌结构功能研究、骨骼肌代谢研究、骨骼肌基因表达研究中的应用,并提出将该技术引入我国航天医学领域的研究中,以期为研究骨骼肌失重防护机制提供理论依据。     

航天员腰痛研究的进展

本文首先综述了航天飞行及模拟失重实验中腰痛的发生情况,以及与航天员腰痛相关的组织在航天及卧床实验中的研究概况;其次,分析了航天飞行任务中航天员发生腰痛的可能机制;最后介绍了相应的对抗措施,旨在为航天飞行中航天员腰痛的防治提供参考。     

模拟失重对成骨样细胞细胞周期变化的影响

目的 探讨空间骨丢失的机理,研究模拟失重时人成骨样细胞细胞周期的变化。方法 利用回转器模拟失重,观察测定了成骨样细胞增殖、周期的变化及其恢复作用和中药三花接骨散对细胞周期的影响。结果 模拟失重作用后,成骨细胞增殖受到明显抑制,Ｇ１期细胞显著增多、Ｓ与Ｇ２＋Ｍ期细胞显著减少,模拟失重１２ｈ后再经１２ｈ以上正常生长,细胞周期可恢复至对照水平。三花接骨散能促进Ｇ１期细胞减少,Ｓ与Ｇ２＋Ｍ期细胞增多,具有     

Aerobic exercise as a countermeasure for microgravity-induced bone loss and muscle atrophy in a rat hindlimb suspension model

BACKGROUND: Loss of bone and skeletal muscle atrophy resulting from non-weight-bearing are major concerns associated with microgravity environment and spaceflight deconditioning. The objective of this research was to address the fundamental issue of whether bone loss and muscle atrophy could be attenuated using weight-bearing aerobic exercise on a treadmill as a countermeasure in rats subjected to simulated weightlessness by hindlimb suspension. METHOD: Bone and muscle from control and hindlimb-suspended groups with and without exercise were evaluated by bone mineral density (BMD), mechanical tests, bone histomorphometry and muscle mass. RESULTS: Femoral BMD of hindlimb-suspended (HS) rats subjected to treadmill exercise was significantly greater than femoral BMD of HS rats without exercise and also was equivalent to that of weight-bearing controls. Muscle mass from HS rats exercised on a treadmill was significantly greater than muscle mass from HS rats that did not exercise. Exercise did not result in muscle mass equal to that of controls, however. In addition, histomorphometric analysis of the metaphysis of the proximal tibia revealed that HS rats that exercised did not maintain bone formation equivalent to controls. No other bone parameters were found to vary significantly between groups. CONCLUSIONS: It was concluded that moderate aerobic exercise on a treadmill did attenuate bone loss and muscle atrophy due to simulated weightlessness by hindlimb suspension, however its effectiveness differed by tissue, anatomical site and parameter investigated.     

维生素K对尾悬吊大鼠骨代谢的影响

目的 探讨维生素K对模拟失重大鼠骨质的影响,为失重骨丢失的防护提供实验依据。方法 将SD雄性大鼠分为3组,自由对照组（FAC）,悬吊对照组（SC）,维生素K悬吊组（SVK）（50mg/kg weight/d),每组9只。每天灌胃给药,实验期为21d。观察维生素K对尾悬吊大鼠血清骨钙素（BGP）、骨生物力学、矿盐含量、一氧化氮（NO）含量及碱性碱酸酶（ALP）活性含量的影响。结果 与SC比较,SVK血清总BGP和结合型BGP,股骨和胫骨矿盐含量,股骨生物力学,胫骨ALP活性含量均显著增加;股骨干NO含量明显减少。结论 维生素K可改善尾悬吊大鼠的骨代谢和骨结构,减少骨丢失,提高骨生物力学性能,降低骨折危险度。     

Alterations in calcium homeostasis and bone during actual and simulated space flight

The weightlessness experienced in space produces alterations in calcium homeostasis. Gemini, Apollo, and Skylab astronauts exhibited a negative calcium balance due primarily to hypercalciuria. In addition, the bone mineral density of the calcaneus declined by approximately 4% in Skylab crew members after 84 d of orbital flight. The negative calcium balance and loss of calcaneal bone mineral in normal adults subjected to prolonged bed rest was comparable to that observed in space. The pathogenesis of bone loss during space flight and bed rest is not well understood due to the lack of histomorphometric data. It is also uncertain whether osteoporotic changes in astronauts are corrected postflight. The observed bone loss would be reversible and of no long-term consequence if the only abnormality was an increased remodeling rate. However, altered bone cell activity would probably result in irreversible bone loss with the premature development of senile osteoporosis many years after space flight. The main skeletal defect in growing rats placed in orbit aboard Soviet Cosmos biosatellites appears to be diminished bone formation. Bone resorption was not elevated during weightlessness. Although cortical bone returned to normal postflight, the decline in trabecular bone mass was somewhat persistent. These studies established that the modeling of a growing skeleton was altered in a weightless environment, but do not necessarily imply that a remodeling imbalance occurs in adults during space flight. However, various forms of simulated space flight inhibited bone formation during both skeletal modeling and the remodeling of adult bone.(ABSTRACT TRUNCATED AT 250 WORDS)     

模拟失重大鼠腰椎骨非胶原蛋白变化与骨矿盐丢失

为研究模拟失重条件下骨质中非胶原蛋白变化与骨矿盐丢失的关系以及了解骨钙素质量是否发生变化，观察了悬吊模拟失重２１ｄ大鼠第３腰椎（Ｌ３）中骨钙素（ＯＣ），白蛋白和矿盐含量的变化，同时也观察了血清ＯＣ与羟磷灰石的结合力。结果显示：悬吊模拟失重大鼠Ｌ３中ＯＣ白蛋白和矿盐含量显著降低，血清总ＯＣ和与羟磷灰石高亲合力ＯＣ显著降低，而与羟磷灰石低亲合力ＯＣ含量无改变。表明悬吊模拟失重大鼠Ｌ３矿盐丢失与骨质中Ｏ     

失重或模拟失重时脑循环的改变

目前对失重条件下脑血流的变化及其时程,研究结果尚不一致,本文综述了失重／模拟失重时脑循环改变的研究成果,阐述了失重／模拟失重对脑循环的可能影响机制及其生理意义,从中可以看出,脑循环改变既是机体自我调节维持脑功能稳定的结果,又是导致脑血管结构重塑、服务态度科导致飞行产位耐力不良的重要原因之一。     

Anabolic steroids as a countermeasure against bone demineralization during space flight

A progressive loss of bone mass is consistently reported in humans exposed to weightlessness during space flight. The mechanism of this metabolic alteration is unknown but may be due in part to the effects of disuse osteoporosis along with the influence of elevated corticosteroid levels. With a goal toward mankind's permanent presence in space, effective countermeasures against bone demineralization will be required. Synthetic anabolic steroids have been shown to prevent bone loss in ground-based immobilization studies and in excess corticosteroid states. These agents may offer a means of slowing or preventing bone loss thus facilitating long term space habitation.     

膳食维生素D和磷水平对悬吊大鼠骨 肌肉与肾的影响

本实验观察了正常和高磷摄入时,补充高量维生素D_3对尾吊(30天)大鼠股骨、腓肠肌和肾成分及其它指标的影响。结果表明,在膳食钙磷含量和比值正常时(Ca:P=0.6%:0.6%),与适量维生素D摄入(膳食维生素D含量为2000IU/kg)比较,高维生素D摄入(10000IU/kg)不但不能减轻悬吊大鼠股骨的骨丢失,反而导致肾脏出现轻度病理变化,腓肠肌萎缩加重,高钙血和血清碱性磷酸酶活性(ALP)增强。在膳食磷含量增加时(1.8%),高维生素D摄入能显著减轻悬吊大鼠股骨的骨丢失,但也加重高磷摄入对肾脏的损伤,并有体重减轻和腓肠肌萎缩加重等副作用。结果提示,在失重和模拟失重条件下,机体对维生素D毒性作用的耐受能力可能减低,补充高剂量维生素D是有害的。     

模拟失重对骨形态发生蛋白2(BMP-2)诱导的ROS17/2.8细胞中ERK活性的影响

目的观察回转器模拟失重对骨形态发生蛋白2（BMP-2）诱导的大鼠骨肉瘤成骨样细胞（ROS17／2．8）中蛋白激酶ERK活性及c-fos／c-jun mRNA表达的影响。方法在地面1G和回转器模拟失重条件下培养ROS17／2．8细胞，按培养时间再分为24h和48h组，各组又分为有或无BMP-2（500ng／ml）组。提取细胞总蛋白，应用免疫沉淀和Western Blotting法检测磷酸化Elk（P-Elk）含量的变化，以反映蛋白激酶ERK的活性。提取细胞总RNA，采用反转录PCR法检测c-fos和c-jun的mRNA表达量。结果BMP-2诱导组的p-Elk表达量明显高于无BMP-2组，各时间点模拟失重组p—Elk表达量均低于1G重力对照组。模拟失重条件下24h和48h组的c-fos mRNA表达较1G对照显著降低（分别为P〈0．05，P〈0．01）。模拟失重条件下48h组的c-jun mRNA的表达显著低于1G对照水平（P〈0．01）。结论模拟失重降低了ROS17／2．8细胞中BMP-2诱导的ERK的活性，且抑制了c-fos和c-jun的基因表达。     

Activity of glycogen-splitting enzymes in the bones of rats after a flight on Cosmos-1129

In order to study the effect of weightlessness on metabolic processes in the bone organic matrix, alpha-amylase and aldolase activities in the ulnar bone of rats flown on Cosmos-1129 were measured. The activity of alpha-amylase and especially of aldolase was increased 6-10 hours after flight. The enzymic changes were the greatest in the animals exposed to weightlessness. The postflight exposure of the rats of the three experimental groups to immobilization produced different changes in the activity of the glycogen-splitting enzymes: it was either stimulated or inhibited. The findings suggest that the enzymes involved in glycogen splitting in the bone organic matrix of rats flown for 18.5 days probably aim at eliminating the adverse effects of weightlessness.