Effects of orbital spaceflight on human osteoblastic cell physiology and gene expression
Effects of orbital spaceflight on human osteoblastic cell physiology and gene expression
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DOI：
10.1016/s8756-3282(00)00234-9
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发表时间：
2000-04-01
期刊：
影响因子：
4.1
通讯作者：
Turner, RT
中科院分区：
文献类型：
--
作者：
Harris, SA;Zhang, M;Turner, RT
在长期的太空飞行中，宇航员会失去骨骼，部分原因是骨骼形成减少。然而，目前尚不清楚重力施加的力是否对骨细胞有直接影响。为了研究骨形成细胞对失重的反应，在17天的STS-80航天飞机任务中培养了人胎儿成骨细胞（hFOB）。在飞行期间和着陆后不久收集条件培养基的部分，分析葡萄糖利用和I型胶原蛋白和前列腺素E-2的积累（PGE(2)）。着陆后从夜间和地面对照培养物中分离总细胞RNA。条件培养基中葡萄糖水平的测量表明，在夜间和地面对照培养基中，葡萄糖利用的速度相似。此外，飞行条件培养基和对照条件培养基中I型胶原蛋白和PGE(2)积累的水平没有区别。在太空飞行后，骨连接素、碱性磷酸酶和骨钙素信使RNA （mRNA）的稳态水平没有显著变化。在夜间培养中，使用RNase保护实验检测到细胞因子和骨骼生长因子mRNA水平的基因特异性降低。白细胞介素(IL)-1 α和IL-6的稳态mRNA水平在夜间8小时后下降，并在飞行后24小时恢复到对照水平。此外，转化生长因子(TGF)- β(2)和TGF- β(1)信息水平在飞行后8小时和24小时略有下降，尽管在8小时的变化没有统计学意义。这些数据表明，太空飞行并没有显著影响hFOB细胞的增殖、I型胶原的表达或PGE(2)的产生，进一步表明从骨组织中去除成骨细胞会导致对失重的反应能力下降。然而，在返回地球之后的太空飞行显著影响了细胞因子和骨骼生长因子的表达，这些因子被认为是骨骼重塑周期的介质。目前尚不清楚后一种变化是由于失重还是由于再入造成的载荷的短暂增加。（骨26:25 -331；2000）(C) 2000由爱思唯尔科学公司。版权所有。
During long-term spaceflight, astronauts lose bone, in part due to a reduction in bone formation. It is not clear, however, whether the force imparted by gravity has direct effects on bone cells. To examine the response of bone forming cells to weightlessness, human fetal osteoblastic (hFOB) cells were cultured during the 17 day STS-80 space shuttle mission. Fractions of conditioned media were collected during flight and shortly after landing for analyses of glucose utilization and accumulation of type I collagen and prostaglandin E-2 (PGE(2)). Total cellular RNA was isolated from night and ground control cultures after landing. Measurement of glucose levels in conditioned media indicated that glucose utilization occurred at a similar rate in night and ground control cultures, Furthermore, the levels of type I collagen and PGE(2) accumulation in the flight and control conditioned media were indistinguishable. The steady-state levels of osteonectin, alkaline phosphatase, and osteocalcin messenger RNA (mRNA) were not significantly changed following space-flight. Gene-specific reductions in mRNA levels for cytokines and skeletal growth factors were detected in the night cultures using RNase protection assays. Steady-state mRNA levels for interleukin (IL)-1 alpha and IL-6 were decreased 8 h following the night and returned to control levels at 24 h postflight. Also, transforming growth factor (TGF)-beta(2) and TGF-beta(1) message levels were modestly reduced at 8 h and 24 h postflight, although the change was not statistically significant at 8 h, These data suggest that spaceflight did not significantly affect hFOB cell proliferation, expression of type I collagen, or PGE(2) production, further suggesting that the removal of osteoblastic cells from the context of the bone tissue results in a reduced ability to respond to weightlessness. However, spaceflight followed by return to earth significantly impacted the expression of cytokines and skeletal grow th factors, which have been implicated as mediators of the bone remodeling cycle. It is not yet clear whether these latter changes were due to weightlessness or to the transient increase in loading resulting from reentry. (Bone 26:325-331; 2000) (C) 2000 by Elsevier Science Inc. All rights reserved.