Molecular cloning related to skeletal or muscle atrophy under microgravity

微重力下骨骼或肌肉萎缩相关的分子克隆

基本信息

批准号：
08557151
负责人：
KITAJIMA Isao
金额：
$ 4.29万
依托单位：
Kagoshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08557151/
关键词：
Space-flight rat bone atrophy remodeling microgravity metal composition mRNA cloning 宇宙飛行傍背柱筋萎縮ストレス蛋白 MEF-2 骨モデリング椎体骨 Diffential display

项目摘要

The effect of 14 days of flight on the vertebrae of rapidly growing rats was studied. No significant difference (p>0.05) was observed between flight rats and ground controls with regard to mechanical hardness or bone mineral density. however, histological examination revealed irregular thickening of the endosteal surface of cortical bones in flight rats, whereas it was uniform in the ground controls. The relative area of lamellar bone showed a significant reduction (p<0.001) in the flight rats. These findings suggest that structural disturbances were due to retardation of endosteal modeling and remodeling. Next, the effects of 14 days of space-flight on beta-adrenoceptor (beta-AR), mitochondrial enzyme activities, and fiber type composition were studied in plantaris muscles. The maximum binding capacity of beta-AR (B max) was significantly lower (>29%) after flight, and the recovery was not complete after 9 days in a 1-G environment. The activity of succinate dehydrogenase (SDH) was measured in muscle samples <5 hr after flight and were found to normalize during 9 days of recovery. It is suggested that the space-flight-induced decrease of B max of beta-AR in plantaris was accompanied by a decreased activity of a mitochondrial inner-membrane enzyme, SDH.Finally, the expression of mRNA in paraspinal muscles between space-flight rats and ground controls was compared using mRNA differential display method in order to identify molecules related to muscle atrophy under microgravity. We found that 70 kDa heat-shock protein (HSP70) and its retated gene, TCP-1, were makedly elevated during 14 days of space-flight, while genes involved in mitochondrial metabolism (mitochondrial adenosine nuclease translocator, mitochondrial cytochrome oxidase subunits), aldolase A and myocyte-specific enhancer binding factor (MEF) were significantly decreased. Some new genes related to muscle atrophy were also detected and we studied the biological functions of these molecules.

研究了 14 天的飞行对快速生长的大鼠椎骨的影响。在机械硬度或骨矿物质密度方面，飞行大鼠和地面对照之间没有观察到显着差异（p>0.05）。然而，组织学检查显示，飞行大鼠皮质骨的骨内膜表面不规则增厚，而地面对照组则均匀增厚。飞行大鼠的板层骨相对面积显着减少（p<0.001）。这些发现表明结构紊乱是由于骨内膜建模和重塑的延迟造成的。接下来，研究了 14 天的太空飞行对跖肌中 β-肾上腺素受体 (β-AR)、线粒体酶活性和纤维类型组成的影响。飞行后β-AR的最大结合能力（B max）显着降低（>29%），并且在1-G环境中9天后恢复尚未完全。飞行后 5 小时内测量肌肉样本中的琥珀酸脱氢酶 (SDH) 活性，并发现在恢复 9 天内恢复正常。表明航天引起的跖肌β-AR B max 的降低伴随着线粒体内膜酶SDH活性的降低。最后，航天大鼠椎旁肌mRNA的表达使用mRNA差异显示方法对地面对照进行比较，以鉴定与微重力下肌肉萎缩相关的分子。我们发现，70 kDa 热休克蛋白 (HSP70) 及其相关基因 TCP-1 在 14 天的太空飞行期间明显升高，而参与线粒体代谢的基因（线粒体腺苷核酸酶转位子、线粒体细胞色素氧化酶亚基）、醛缩酶 A 和肌细胞特异性增强子结合因子 (MEF) 显着降低。还检测到了一些与肌肉萎缩相关的新基因，我们研究了这些分子的生物学功能。