周期性张应力对面颌肌细胞Na^+/K^+-ATPase的影响

The Effects of Na^+/K^+-ATPase Activity and α-Subunits Expression by Mechanical Strain in Cultured Maxillofacial Skeletal Muscle Cells in Vitro

目的:研究周期性张应力对Na+/K+-ATPase功能活性及其表达的影响,明确Na+/K+-ATPase在功能矫形中面颌肌肉适应性改建的生物和分子机制。方法:构建面颌肌细胞体外培养-力学刺激模型;应用多通道细胞牵张应力加载系统,对面颌肌细胞施加不同时段的张应力刺激,测定Na+/K+-ATPase的功能活性;运用实时荧光定量PCR研究周期性张应力刺激对Na+/K+-ATPase功能亚基α亚单位mRNA的影响。结果:Na+/K+-ATPaseα1,α2亚单位随着加力时间延长,表达增强,同对照组比较,呈一致性上调(P<0.001);细胞加力1小时,α1的mRNA表达不受影响;加力2小时后,α1和α2的mRNA表达呈现逐渐增强趋势,48 h时达到最大值。张应力刺激对α2亚单位的mRNA表达似乎更为敏感,加力1 h时α2亚单位的mRNA表达水平即增加,增加量约为对照组的37.74%,具有显著的统计学意义。结论:周期性的机械牵张作用于培养的骨骼肌细胞,可诱导α1和α2亚单位mRNA的表达量增加;α1和α2亚单位对周期性张应力刺激的作用时间反应不同,α2亚单位的反应可能更为敏感。周期性张力刺激的增加所产生的压力可能是转录调节的主要因素;周期性张应力对骨骼肌细胞Na+/K+-ATPase水解亚的调节作用不同,可能在面颌肌肉对功能矫形力的适应性改建中具有重要作用。

Objective： To investigate the effect and mechanism of Cyclic,mechanical stretch on Na＋/K＋-ATPase function and the expression of its functional isoform-α subunits after a SD rats maxillofacial skeletal muscle cell culture model was builted.Methods： In vitro culture-tensile stimulate models of Maxillofacial Skeletal Muscle Cells were established successfully.Cyclic,mechanical stretch was applied on the cells for 1,2,12,24 and 48 hours with Periodic mechanical stretch at an optimal magnitude and frequency.Real-time quantitative PCR was used to detect the effects of Na＋/K＋-ATPase activity and α-subunits expression.Results： The expressions of α1-subunit and α2-subunit of Na＋/K＋-ATPase were found to be enhanced apparently during the mechanical stretch.A significant increase in the levels of α2-subunit of Na＋/K＋-ATPase was observed after 1h of mechanical stretch.However,no effect of α1-subunit of Na＋/K＋-ATPase was found after 1h of mechanical stretch.The expressions of α1-subunit and α2-subunit of Na＋/K＋-ATPase were increased gradually after 2h of mechanical stretch,reaching a maximum after 48h of mechanical stretch.Conclusion： Cyclic stretch stimulates the mRNA expression of both α1-and α2-subunits of Na＋/K＋-ATPase.The sensitivity of the two genes to the degree and duration of stretch was different.The stretch-induced increase of mRNA might be a result of increased transcription.Cyclic,mechanical stretch also induced a significant upregulation of both the α1-and α2-subunits.