机械张应力对PLGA-胶原复合支架上大鼠成肌细胞桩蛋白表达变化的影响

Tensile stress effects on the expression of paxillin in rat myoblasts cultured in a three-dimensional PLGA-collagen scaffolds

目的:研究不同时间、不同强度的张应力对三维支架复合培养的大鼠成肌细胞桩蛋白paxillin表达的影响,探讨机械张应力刺激作用下复合培养成肌细胞早期力学信号转导机制。方法:首先,利用电纺法制备PLGA(polylactide-co-glycolide)-胶原复合生物支架,并与大鼠成肌细胞复合培养;然后,应用四点弯曲细胞力学加载装置对其进行力学加载,收集细胞,采用免疫印迹(Western Bloting)法,研究周期性单轴机械张应力刺激下PLGA-胶原复合支架上大鼠成肌细胞磷酸化桩蛋白p-paxillin(Tyr 118)/paxillin的表达变化。结果:无论1000μstrain或2000μstrain的张应力刺激,均可诱导paxillin的磷酸化过程,且随加载时间延长,磷酸化程度上调;2000μst rai n的张应力较1000μstrain激活paxillin磷酸化过程的效应更明显、迅速。结论:①周期性单轴牵张应变可以在加载早期通过Tyr118位点的磷酸化而激活桩蛋白paxillin;②周期性牵张应变对复合培养成肌细胞paxillin蛋白表达的影响,与应力刺激的力值有关。

Objective To study different intensity and different time of tensile stress effects on the expression of paxillin in rat myoblasts cultured compositely.Preliminarily discuss the initial mechanotransduction of cultured myoblasts with stimulation of mechanical tension stress,to reveal finally the mechanism of mechanotransduction of myoblasts cultured in a three-dimensional PLGA-collagen scaffold.Methods Three-dimensional PLGA-collagen scaffolds were prepared using electrospinning method,and cultred compositely with the rat myoblasts to constuct three-dimensional culture complex.A cyclic strain loading apparatus-＂Forcel＂ four point bending device was used for mechanically loading.Examine the expression of p-paxillin（Tyr118）/paxillin in rat myoblasts with simulation of cyclic uniaxial mechanical tensile stress after Western Bloting method.Results The tensile stress stimulation of 1000μstrain or 2000μstrain can induce the phosphorylation of paxillin protein.And the phosphorylation level increases with the time extension.Compared 1000μstrain tensile stress stimulation,2000μstrain tensile stress stimulation could induced more rapid,more intense phosphorylation of paxillin protein.Conclusion ①Cyclic uniaxial tensile stress early could activate paxillin in myoblasts by phosphorylation of Tyr118;②Cyclic tensile stress effects on expression of paxillin protein in myoblasts cultured compositely relate to the intensity of stress.