周期性单轴压应力下大鼠髁突软骨细胞早期应答机制的蛋白质组学初探

目的探讨体外周期性单轴压应力对大鼠髁突软骨细胞蛋白质表达的早期影响，为阐明髁突软骨细胞的力学应答反应机制奠定基础。方法对第三代大鼠髁突软骨细胞进行周期性单轴压应力加载，分为2000μstrain加力组和对照组、4000μstrain加力组和对照组，加力时间为60min；采用双向凝胶电泳技术和质谱鉴定分析软骨细胞蛋白质表达的变化。结果与对照组相比，2000μstrain加力组细胞蛋白质表达变化无统计学意义（P〉0．05）；4000μstrain加力组细胞蛋白质表达改变，3个新蛋白点出现，5个蛋白点消失，22个蛋白点表达下调，7个蛋白点表达升高（P〈0．05）。质谱鉴定其中8个差异蛋白点分别为细胞骨架相关蛋白（丙种肌动蛋白和中间丝波形蛋白）、糖代谢相关蛋白（烯醇酶α和应激70糖调控蛋白）、信号传导相关蛋白（Raf激酶抑制蛋白），以及几种蛋白复合物。结论在体外4000μstrain周期性单轴压应力刺激下，大鼠髁突软骨细胞的蛋白表达谱明显改变，这些差异蛋白可能参与早期的力学应答反应。

Early-response of the condylar chondrocyte under cyclic uniaxial compressive stress

OBJECTIVE: To investigate the protein profile after treatment of the cyclic uniaxial compressive stress on the rat condylar chondrocyte in vitro. METHODS: The third-passage chondrocytes were harvested from the mandibular condyles of 2-day-old rats, and a cellular compressive stress device (self-made four-point bending system) was used to apply stress on cells at 2000 microstrain and 4000 microstrain (0.5 Hz frequency) for 60 min. The early effects of cyclic uniaxial compressive stress on the protein profile of the rat mandibular condylar chondrocytes were examined by two dimensional polycrylamide gel electrophoresis (2D-PAGE) and matrix-assisted laser-desorption ionization time of flight massspectrometry (MALDI-TOF-MS). RESULTS: The results showed that the protein profile of the condylar chondrocyte did not change statistically in 2000 microstrain group. In 4000 microstrain group, the protein profile of the condylar chondrocyte was changed. Three new proteins appeared. Five proteins disappeared. Twenty-two proteins were down-regulated and 7 proteins were up-regulated (P < 0.05). The eight different protein spots were identified by MALDI-TOF-MS. It included cytoskeleton protein (gamma-actin and vimentin), glycometabolism protein (alpha enolase and stress-70 protein) and signal transduction protein (Raf kinase inhibited protein, RKLP). CONCLUSIONS: There were significant alternations of the protein profile in the rat condylar chondrocyte after the 4000 microstrain cyclic uniaxial compressive stress loading for 60 min. These different proteins might take part in the early response to the cyclic uniaxial compressive stress.