周期性单轴压应力对大鼠髁突软骨细胞Stress70/GRP75的早期影响

目的:探讨体外周期性单轴压应力对大鼠髁突软骨细胞糖调控蛋白Stress70/GRP75的早期动态变化影响。方法:利用四点弯曲细胞力学加载仪,对第3代大鼠髁突软骨细胞进行体外周期性单轴压应力加载,力值为4000μstrain,时间分别为0、15、30、60、120、240min;采用Western免疫印迹技术和图像分析技术,研究大鼠髁突软骨细胞糖调控蛋白Stress70/GRP75的动态变化,对结果进行单因素方差分析。结果:4000μstrain周期性单轴压应力作用下,大鼠髁突软骨细胞糖调控蛋白Stress70/GRP75的表达发生变化,0min条带灰度值为114.2±5.08;30min时降至最低,为86.1±5.09(P<0.001);60min后有所回升,至104.0±4.41(P<0.01),但仍表达下调;120min后表达开始增强,灰度值为134.5±3.74(P<0.001)。结论:4000μstrain压应力刺激,对大鼠髁突软骨细胞糖调控蛋白Stress70/GRP75存在时间效应性,初期表达下调;随着应力加载时间延长,其表达反馈增强。

Early effects of the cyclic uniaxial compressive stress on Stress70/GRP75 in the rat condylar chondrocytes

PURPOSE: The purpose of this study was to investigate the early effects of the cyclic uniaxial compressive stress on Stress70/GRP75 in the rat condylar chondrocyte. METHODS: The third-passage chondrocytes were harvested from the mandibular condyles of 2-day-old rats for this study, and a cellular compressive stress device (self-made four-point bending system, Patent No.01129166.4 & 01256849.x) was used to apply stress on cells at 4000 microstrain (0.5 Hz frequency) for 0, 15, 30, 60, 120, 240 minutes respectively. The early effects of the cyclic uniaxial compressive stress on Stress70/GRP75 in the rat mandibular condylar chondrocytes were examined by Western blot and image analysis. One-way ANOVA was used for statistical analysis. RESULTS: The results showed that the expression of Stress70/GRP75 changed significantly with 4000 microstrain compressive stress loading. The gray scale value of protein band at 0 minute was 114.2+/-5.08, significantly decreased to 86.1+/-5.09 (P<0.001) after 30 minutes, and then gradually increased to 104.0+/-4.41 (P<0.01) at 60 minutes. The expression of Stress70/GRP75 up-regulated to 134.5+/-3.74 (P<0.001) at 120 minutes, and continued to increase within 240 minutes. CONCLUSION: There is time-dependent response between the 4000 microstrain compressive stress stimulate and Stress70/GRP75. The expression of Stress70/GRP75 inhibited initially under the compressive stress, and then increased by feedback with the increased loading time.