模拟失重对流体剪切应力致大鼠颅骨成骨细胞PGE2分泌的影响

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：传统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（5－60min)，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＜0．01）；而在一定的剪切应力范围内（0．5－1．5Pa)，细胞PGE2的分泌反应与应力水平无明显关系，即应性下降，即0．5Pa应力上无PGE2的分泌反应（P＜0．01），1．5Pa应力作用下PGE2的分泌延缓并且分泌水平下降（P＜0．01）。结论：成骨细胞对流体剪切应反应在模拟失重环境下有下调性改变／

Effects of Simulated Weightlessness on the Release of PGE2 in Rat Calvarial Osteoblasts Induced by Flow Shear Stress

Objective: To observe the effects of simulated weightlessness on the release of prostaglandin E2 in rat calvarial osteoblasts by flow shear stress (FSS). Method: Osteoblasts were isolated from neonatal rat calvariae and then were set to two groups. One was cultured in 1 G terrestrial gravitational environment. The other was cultured on a clinostat (simulating weightlessness environment) for 60 h, then the osteoblasts were treated with 0.5 Pa or 1.5 Pa FSS in a flow chamber for 1 h. Then release of PGE2 in the osteoblasts was determined. Result: 0.5 Pa and 1.5 Pa FSS treatments significantly increased the release of PGE2 in osteoblasts cultured in 1 G environment (P < 0.01) , but there was no remarkable difference between the responses of 0.5 Pa FSS treatment group and 1.5 Pa group (P > 0.05). By contrast, in cells cultured in simulated weightlessness environment, no detectable release of PGE2 was found with the treatment of 0.5 Pa FSS (P < 0.01). The release of PGE2 was delayed and the amount of PGE2 Production was remarkably decreased with 1.5 Pa FSS treatment (P < 0.01). Conclusion: These results demonstrated that the responsiveness of osteoblasts to FSS was down-regulated in simulated weightlessness.