不同重力环境对流体剪切应力致成骨细胞前列腺素E_2分泌的影响

目的　观察不同重力环境对流体剪切应力致成骨细胞前列腺素 E2 (PGE2 )分泌的变化 ,探讨重力变化对成骨细胞力学信号转导功能的影响。　方法　传代培养的大鼠乳鼠颅骨成骨细胞分别在 1G、3G及模拟失重环境中培养。6 0 h后 ,将成骨细胞置于流体槽中给予 0 .5 Pa或 1.5 Pa的流体剪切应力作用 1h,检测细胞分泌 PGE2 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～ 6 0 m in) ,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 .5～ 1.5 Pa) ,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有显著性下降 (P<0 .0 1) ,0 .5 Pa应力作用下无 PGE2 的分泌反应 ,1.5 Pa应力作用下虽有 PGE2 的分泌 ,但分泌延缓且水平下降 (P<0 .0 1)。3G重力环境下 ,细胞对剪切应力的反应特性与 1G重力组细胞的表现相比 ,差异无显著性意义 (P>0 .0 5 )。　结论　模拟失重可以导致大鼠成骨细胞力学信号转导功能的下降 ;3G重力环境对成骨细胞的力学信号转导功能无显著影响

The influence of different gravitational environments on the release of PGE_2 in osteoblasts induced by fluid shear stress

Objective To observe the effect of different gravitational environments on the release of prostaglandin E 2 in osteobalsts induced by fluid shear stress (FSS) so that to explore the influence of change of gravity on mechanotransduction in osteoblasts. Methods Osteoblasts were isolated from neonatal rat calvariae and cultured in a set of bottles. They were randomly divided into 3 groups, and cultured in 3 gravitational environments: 1 G environment(control), simulated weightlessness and 3 G gravitational environment for 60 h. Then osteoblasts were treated with 0.5 Pa or 1.5 Pa FSS in a flow chamber for 60 min, and the median samples were taken in the course of FSS treatment and assayed for PGE 2 concentration. Results In 1 G gravitational environment, the secretion of PGE 2 was significantly enhanced along with the sustaining of FSS treatment ( P < 0.01 ), but there was no remarkable difference between the responses to 0.5 Pa FSS and 1.5 Pa ( P > 0.05 ). While in simulated weightlessness environment group, no detectable PGE 2 release reaction was found with the treatment of 0.5 Pa FSS ( P <0.01), and the release of PGE 2 was delayed and the amount of PGE 2 production was remarkably decreased with 1.5 Pa FSS treatment as compared with that of control ( P <0.01). The responsiveness of osteoblasts cultured in 3 G gravitational environment to FSS was similar with that of control. Conclusion These results indicated that the mechanotransduction in osteoblasts was down regulated in stimulated weightlessness,whereas it was not altered in 3 G gravitational environment.