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目的为探讨失重环境对骨骼细胞的力学信号转导功能的影响 ,细胞这种功能的变化在失重性骨质稀少中的作用 ,以及空间飞行锻炼效果不良与之的关系。观察了模拟失重对流体剪切应力致大鼠成骨细胞PGE2 分泌的影响。方法传代培养的大鼠乳鼠颅骨成骨细胞分为两组 ,一组在地面重力环境下培养 ,另一组则置于回转器中培养 60h。然后 ,将成骨细胞置于流体槽中给予 0 .5Pa或 1 .5Pa的流体剪切应力作用 1h ,检测细胞分泌前列腺素E2 的变化。结果在 1G重力环境下培养的成骨细胞中 ,在一定的时间范围内 ( 560min) ,细胞PGE2 的分泌反应随剪切应力作用时间的延长而显著增强 (P <0 .0 1 ) ;而在一定的剪切应力范围内 ( 0 .51 .5Pa) ,细胞PGE2 的分泌反应与应力水平无明显关系 ,即不随剪切应力的大小而改变 (P >0 .0 5)。与之相比 ,模拟失重环境下培养的成骨细胞对剪切应力的反应性下降 ,即 0 .5Pa应力作用下无PGE2 的分泌反应 (P <0 .0 1 ) ,1 .5Pa应力作用下PGE2 的分泌延缓并且分泌水平下降 (P <0 .0 1 )。结论成骨细胞对流体剪切应力的反应性在模拟失重环境下有下调性改变
Objective To investigate the effect of weightlessness on mechanistic signal transduction of skeletal cells, the role of cellular changes in weightlessness in osteopenia and the effect of poor aerobic exercise on space flight. The effect of simulated weightlessness on the secretion of PGE2 in rat osteoblasts induced by fluid shear stress was observed. Methods The cultured rat suckling rat skull osteoblasts were divided into two groups. One group was cultured on the ground under the gravity environment. The other group was placed in a rotator and cultured for 60 hours. Then, the osteoblasts were placed in the fluid tank to give 0.5Pa or 1.5Pa fluid shear stress for 1h, the cells were assayed for changes in prostaglandin E2. Results In osteoblast cultured in 1G gravity environment, the secretion of PGE2 was significantly increased with the increase of shear stress time (560 min) in a certain time (P <0.01) Within a certain range of shear stress (0 .51 .5 Pa), the secretion of PGE2 in cells was not related to the stress level, that is, it did not change with the shear stress (P> 0.05). In contrast, the osteoblasts cultured under simulated weightlessness decreased in response to shear stress, that is, no secretion of PGE2 was observed under the stress of 0.5 Pa (P <0.01). Under the stress of 1.5 Pa Secretion of PGE2 was delayed and secretion was decreased (P <0.01). Conclusion The reactivity of osteoblasts to fluid shear stress is down-regulated under simulated weightlessness