模拟失重大鼠肺组织显微结构和一氧化氮合酶表达的动态变化

目的 观察模拟失重对大鼠肺组织显微结构及其一氧化氮合酶(NOS)表达的影响,为模拟失重时肺组织的适应机制研究积累资料.方法 采用Wistar雄性大鼠-30°尾部悬吊模拟失重生理效应.常规光镜和免疫组织化学方法 观察悬吊7 d组(TS7)、14 d组(TS14)及对照组(Con)肺组织显微结构和结构型NOS(cNOS)、诱导型NOS(iNOS)表达.结果 TS7组大鼠出现肺实变、肺水肿、支气管黏膜内淋巴细胞浸润、肺泡内有红细胞及肺泡融合.TS14组大鼠肺病变较TS7组大鼠明显加重,表现为肺泡融合增多、肺泡内更多红细胞和肺泡壁增厚.各组大鼠肺组织cNOS表达区域主要为支气管上皮细胞、血管内皮细胞和平滑肌细胞,各组间表达水平无统计学差异.iNOS表达在TS7、TS14组血管内皮细胞和平滑肌细胞表达显著增多,其中TS14组血管内皮细胞表达量高于TS7组.结论 模拟失重大鼠肺组织形态学变化可能与肺循环iNOS表达增加有关.     

Adaptive modifications of postural attitude in conditions of weightlessness

Summary Adaptation of static posture was studied before, during, and after a 7-day space flight. Body segment orientations, body stability, and muscle activity underlying the reproduction of several postural attitudes were examined in various visual situations either with the shoes attached to the floor or during free floating. In standing or relaxed subjects whose shoes were attached to the floor, the tonic activity of the ankle flexor was enhanced relative to that in the same posture on earth, whereas the extensor activity disappeared. Errors in attempting to reproduce the normal terrestrial upright posture and a forward-leaning posture were accompanied by major changes in the synergies between neck, hip, knee, and ankle joints. These changes are mainly attributed to cumulative adjustments in response to nonvestibular signals such as tactile, articular, and proprioceptive cues.     

模拟失重及高+Gx对猴舌横纹肌细胞结构及HSP70表达的影响

目的探讨模拟失重及高+Gx对猴舌横纹肌组织结构和热休克蛋白70(heat shock protein 70,HSP70)表达的影响。方法 12只雄性猕猴随机分为4组,正常对照组(A)、30d模拟失重组(B),+13Gx/230s组(C)、30d模拟失重后超重组(D),其中D组根据过载峰值又分为+11Gx/270s(D1)、+13Gx/230s(D2)和+15Gx/200s(D3)。动物放血处死后取材,采用组织病理学和免疫组化的方法,观察猴舌横纹肌组织结构及HSP70的表达情况。结果 A组可见正常的舌横纹肌结构,其他组舌横纹肌细胞结构基本正常,偶见细胞间质稀疏,细胞排列紊乱以及横纹不清或消失。A组舌横纹肌细胞HSP70呈阴性表达,细胞核与细胞浆均无明显着色;B组、C组和D组舌横纹肌细胞胞核与胞浆均着色明显,呈阳性表达,较A组变化显著。HSP70免疫组化积分显示,D组比B组和C组变化显著(P<0.05),但D1、D2、D3无明显差别(P>0.05)。结论 30d模拟失重和高+13Gx/230s均可使猴舌横纹肌细胞产生应激反应,引起HSP70的表达增强,并可能伴有损伤。模拟失重与过载超重具有协同作用,两者可能加重了对舌横纹肌的影响。     

模拟失重状态下大鼠抗肺炎链球菌感染能力的变化

目的 观察模拟航天失重状态下呼吸道感染肺炎链球菌后抗感染能力的变化,为航天医疗保障提供依据.方法 建立模拟失重状态下大鼠链球菌肺炎模型,将32只健康雄性清洁级Wistar大鼠按随机数字表法分为4组:悬吊注菌组(A组)、悬吊未注菌组(B组)、未悬吊注菌组(C组)及未悬吊未注菌组(D组),每组8只,采用国内外公认成熟的尾悬吊法(身体纵轴与水平面约成30°)模拟失重状态,悬吊第4天通过气管捕管法将0.4ml(细菌浓度约9.0×108 CFU/ml)的标准肺炎链球菌菌株(ATCC6303,血清型3型,美国菌种保藏中心保存)注入肺组织,建立肺炎链球菌感染模型,对照组同时注入同等量的无菌生理盐水,仅注入1次.悬吊7d后取材,测定血常规、C反应蛋白及CD4+/CD8+.观察肺组织(每组均取右肺上叶)的炎症反应,并测量实验前后动物体重的变化.结果 A组肺组织表面凹凸不平,呈颗粒样改变,光镜下可见较严重的肺淤血和小静脉、毛细血管充盈扩张,肺泡融合增多,肺泡间隔增厚及肺泡腔受压变形,B、C组也可见部分上述改变,但程度较轻.各组间白细胞总数未见明显差异(F=1.57,P=0.22);A组中性粒细胞数为(2.4±0.5)×109/L,B组为(2.0±0.3)×109/L,C组为(1.7±0.4)×109/L,均高于D组的(1.2±0.2)×109/L(u值分别为0、1.0和8.5,均P＜0.05),A组与C组比较,差异有统计学意义(u=9.0,P=0.02).中性粒细胞百分比A组为0.26±0.04,高于C组的0.19±0.05(u =8.5,P=0.01);B组为0.23±0.03,C组为0.19±0.05,均高于D组的0.15±0.02(u值分别为2.0和13.0,均P＜0.05),而B组和C组比较差异无统计学意义(u=20.0,P=0.21);各组淋巴细胞总数比较差异无统计学意义(F=0.72,P=0.55),但A组[(6.0±0.9)×109/L]低于D组[(6.3±0.6) ×109/L];淋巴细胞百分比A组为0.66±0.08,B组为0.68±0.05,均低于D组的0.79±0.02 (F=10.24,P＜0.001).A组C反应蛋白为(11.9±2.2) g/L,明显高于D组的(1.5±0.8)g/L (u =0,P =0.001);4组CD4+/CD8+比值无明显差别(F=1.23,P=0.32);与其他组比较,A组体重减轻最明显,差异有统计学意义(F=122.07,P＜0.001).结论 失重状态下大鼠机体免疫功能降低,抗肺炎链球菌感染能力降低,肺部炎症反应更强,体重减轻更明显,需要给予相应的保障措施.     

机械振动防治失重性骨质疏松的研究进展

随着载人空间站发展,在军事和民用都有着巨大应用价值,载人航天器围绕地球旋转时,由于离心力与重力相平衡,理论上其内部为零重力,这称之为失重。对于失重下的减少骨量丢失,药物预防或者治疗尚未达到理想的效果,并不能阻止失重状态下骨量的丢失,目前的研究证明了采用机械振动的方法可能是一种有效防治失重性骨质疏松的措施。因此本文对机械振动在动物、细胞、临床方面的研究现状以及防治失重性骨质疏松方面的临床应用前景进行综述。     

应用微重力旋转培养系统构建组织工程软骨的实验研究

目的探讨微重力旋转培养系统(RCCS)在构建组织工程细胞/载体复合物修复兔关节软骨缺损中的作用。方法将兔骨髓间充质干细胞附着在三维载体壳聚糖上,分为传统的静置培养组和微重力旋转培养组,经过体外成软骨诱导作用后,修复兔关节软骨缺损。考察不同时间点、不同培养体系中细胞增殖情况、成软骨表达情况以及对兔关节软骨缺损的修复情况。结果相对于常规的静置培养组,RCCS组细胞增殖能力、成软骨表达均得到增强,对兔关节软骨缺损的修复更为有效。结论微重力旋转培养系统可以作为构建组织工程软骨一个有效的辅助手段,进而应用临床软骨缺损的修复。     

Caloric stimulation during short episodes of microgravity

Summary Caloric testing was performed during parabolic flight at the NASA Reduced Gravity Facility in Houston, Texas. Six test subjects were stimulated with continuous unilateral air insufflation (25°R), in a manner similar to the experiments performed in the extended weightlessness of orbital flight during the SL1 and D1 Spacelab missions. Nystagmus response was recorded by electro-oculography and eye video image. It was the purpose of the experiments to re-examine the apparent discrepancy between the disappearance of caloric nystagmus during short episodes of weightlessness and the finding that caloric responses can be elicited during periods of extended weightlessness. The present results agree with those of earlier experiments in that a prompt reduction of caloric nystagmus occurs on transition from hypergravity (1.8 G) to weightlessness. The time constant of nystagmus decay was estimated to be approximately 2–3s, a value which cannot be explained by cupular mechanics. A central gating mechanism involving the labyrinthine canal and otolithic afferents is proposed for the observed modulation of caloric nystagmus.     

Effect of spaceflight on thresholds of perception of angular and linear motion

Summary Psychophysical studies of vestibular function have been carried out in order to study adaptation within the vestibular sensory system to the weightless environment of orbital spaceflight. No significant change in the threshold of detection of whole-body angular acceleration was found, either during flight or post-flight. Experiments involving the perception of whole-body linear acceleration have yielded somewhat inconsistent results, although the weight of evidence points to an elevation and increased variability of threshold in the first few days following spaceflight. Although a change in the excitability of the saccular and macular otoliths in microgravity cannot be excluded, it is more probable that this decreased sensitivity is a manifestation of a central adaptive mechanism, in which the weighting of gravi-receptor information is reduced. Enhancement of the ability to detect linear acceleration stimuli, exhibited by some astronauts in microgravity, may be a manifestation of heightened utilization of cutaneous rather than otolithic cues.Part of the Round Table Conference presented at the Collegium ORLAS, Munich, Federal Republic of Germany, 7–10 September 1986     

套带与下体负压对-6°头低位卧床21天的健康男性心脏X线变化的影响

目的　探讨头低位卧床模拟失重过程中心脏 X线形态变化及四肢加压套带、下体负压的作用。　方法　 18名健康男性青年 ,自愿接受试验 ,随机分为对照组、套带组和下体负压组 ,进行- 6°头低位卧床 2 1d试验。对照组卧床中不用任何对抗措施 ;套带组卧床期间每天 0 8∶ 30～ 2 0∶ 30 ,四肢戴加压套带 ,压力维持在 5 .3k Pa;下体负压组卧床期间第 1周和最后 1周每天下午使用 1h下体负压裤 ,压力维持在 - 4k Pa。分别于卧床前 1d和卧床后 1d摄取 X线胸片 1张 ,按有关标准测量胸廊横径、心脏横径、长径和宽径 ,并计算反映心脏形态大小的心胸比和心脏面积。　结果　对照组卧床后较卧床前心脏横径减小 0 .5 4cm,心胸比减小 0 .0 2 4,心脏面积减小 9cm2 ,差异有显著性意义。套带组和下体负压组心脏面积前后比较差异无显著性意义。　结论　头低位卧床 2 1d模拟失重过程可使心脏体积变小 ,这可能是心脏功能降低的结果 ,与有关实验结果相符 ;使用四肢加压套带和下体负压等对抗措施可以防止心脏形态改变 ,而下体负压作用效果及可操作性均优于四肢加压套带。     

模拟失重对人体骨骼肌体积和肌内乙酰胆碱/肌酸比值的影响及等张运动对肌萎缩的作用

目的：研究模拟失重对人体骨骼肌体积和肌内乙酰胆碱／肌酸（Cho/Cr)比值的影响，并观察卧床期等张肌肉锻炼的抗肌萎缩作用。方法：10名健康青年男性志愿者，进行卧床3周的模拟失重试验，将其随机分为卧床对照组（5人）和卧床运动训练组（5人）。使用核磁共振成像和磁共振波谱观察卧床前后右侧大腿骨骼肌体积，肌四头肌体积和比目鱼肌内Cho/Cr的变化，使用REV9000等速测力系统测试其膝关节伸肌相对峰力矩的变化。结果：两组受试者卧床后右侧大腿骨骼肌体积、肌四头肌体积和膝关节伸肌相对峰力矩除Cho/Cr外均较卧床前显著下降，以股四头肌体积变化最显著。对照组与训练组间差异无显著性意义。结论：模拟失重对人体下肢骨骼肌短期内即可出现以伸肌为主的萎缩和膝关节伸肌相对峰力矩的下降。本组数据未能显示出等张运动对抗肌萎缩有显著的作用。