体外周期性单轴压应力作用下大鼠髁突软骨细胞肌动蛋白和中间丝波形蛋白的早期变化研究

目的探讨体外周期性单轴压应力对大鼠髁突软骨细胞细胞骨架蛋白肌动蛋白（Actin）和中间丝波形蛋白（Vimentin）的早期影响。方法利用四点弯曲加力装置对第3代大鼠髁突软骨细胞进行周期性单轴压应力加载，力值为4 000 μstrain，时间为15、30、60、120、240 min。同时设有不加力的对照组。采用免疫荧光技术和Westernblot免疫印迹技术研究大鼠髁突软骨细胞在周期性单轴压应力作用下Actin和Vimentin的早期动态变化。结果在4 000 μstrain压应力作用下，细胞骨架荧光逐渐下调，60 min表达最低，但120 min后细胞骨架的荧光表达逐渐恢复。Vimentin蛋白表达水平在30 min开始下降，Actin蛋白表达在60 min明显下调，几乎消失；但120 min后两种蛋白表达水平开始迅速回升。结论4 000 μstrain压应力刺激对大鼠髁突软骨细胞Actin、Vimentin蛋白的表达存在时间效应性，表现为先下调后反馈增强的趋势，提示细胞对力学刺激的反应存在“自我调控保护”的机制。

Early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat condylar chondrocytes

OBJECTIVE: To investigate the early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat condylar chondrocyte. METHODS: The third-passage chondrocyte were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device was used to apply stress on cells at 4 000 microstrain for 15, 30, 60, 120, 240 min. The early effects of the cyclic uniaxial compressive stress on Actin and Vimentin of the rat mandibular condylar chondrocytes were examined by laser scanning confocal microscope (LSCM), immunofluorescence technique and Western blot. RESULTS: The expression of fluorescent light of cys-toskeleton protein changed obviously with 4000 microstrain compressive stress loading. The expression of Actin significantly decreased in 60 min, and the expression of Vimentin decreased in 30 min. Then the expression of these two protein recovered in 120 min. CONCLUSION: There are time-responsiveness between the 4000 microstrain compressive stress stimulate and Actin, Vimentin. It shows the expression of Actin and Vimentin down-regulated at first under the compressive stress, then increased by feedback. It hints that there are "self-regulate" mechanisms in the cell response to mechanics stimulate.