脉冲电磁场促进成骨细胞成熟分化依赖于初级纤毛-PI3K/AKT途径  

Pulsed electromagnetic fields stimulating osteogenic differentiation and maturation involves primary cilia-PI3K/AKT pathway

作　　者：任茜[1] 周建[1] 王鸣刚[2] 陈克明[1] REN Qian;ZHOU Jian;WANG Ming-gang;CHEN Ke-ming(Institute of Orthopaedics, Lanzhou General Hospital of PLA, Lanzhou 730050, China;College of Life Science and Engineering,Lanzhou University of Technology, Lanzhou 730050, China)

机构地区：[1]兰州军区兰州总医院骨科研究所,兰州730050 [2]兰州理工大学生命科学与工程学院,兰州730050

出　　处：《北京大学学报（医学版）》2019年第2期245-251,共7页Journal of Peking University:Health Sciences

基　　金：国家自然科学基金(81270963;81471090);甘肃省自然科学基金(1506RJZA306)~~

摘　　要：目的:研究脉冲电磁场(pulse electromagnetic fields,PEMF)促进大鼠成骨细胞成熟分化是否与初级纤毛和PI3K/AKT途径相关,探讨PEMF促进骨形成的作用机制。方法:用酶解法获取新生SD大鼠颅骨成骨细胞(rat calvarial osteoblasts,ROB),50 Hz、0.6 m T PEMF处理0、0.5、1、1.5和2 h后检测磷脂酰肌醇-3-激酶(phosphatidylinositol-3-kinase,PI3K)和蛋白激酶B(protein kinase B,AKT)蛋白表达量及初级纤毛长度和发生率的变化情况;用LY294002阻断PI3K/AKT信号途径,观察PEMF促进ROB成骨性分化是否受到影响;以RNAi法干扰IFT88的基因表达以抑制初级纤毛发生,观察PEMF激活的PI3K/AKT信号途径及ROB的成骨性分化是否受到影响。成骨性分化指标包括碱性磷酸酶(alkaline phosphatase,ALP)活性,real-time PCR法和Western blot法检测的成骨性相关基因BMP-2、COL-1和OSX的基因表达量,以及钙化结节数量等。结果:经PEMF处理0、0.5、1、1.5、2 h后,ROB的PI3K、AKT蛋白表达量升高(P<0.01),初级纤毛变长;其中PI3K在0.5 h时蛋白表达量达到最高,随着PEMF处理时间增加,蛋白表达量降低;AKT在0.5 h和1.5 h时蛋白表达量较高。用PI3K阻断剂LY294002阻断PI3K/AKT信号途径后,PEMF不再能提高成骨细胞中ALP活性和成骨性相关基因BMP-2、COL-1、OSX的基因表达量,但在阻断前PEMF能增加ROB中ALP活性和成骨性相关基因的表达;RNAi干扰初级纤毛发生后,PEMF不再能增加PI3K的蛋白表达量,说明初级纤毛干扰后,PEMF不能激活PI3K/AKT信号途径;其次,PEMF提高ALP活性的作用消失,也不能提高BMP-2、COL-1和OSX的基因表达量,其增加ROB钙化结节形成能力的作用也消失,说明初级纤毛干扰后,PEMF促进成骨细胞成熟矿化的能力消失。结论:PEMF通过成骨细胞表面的初级纤毛激活了PI3K/AKT信号途径,进而发挥了骨形成活性的促进作用。Objective: To study whether the pulsed electromagnetic fields (PEMF) promoting rat osteoblasts differentiation and maturation is related to the primary cilia and PI3K/AKT pathway, and to explore the mechanism of PEMF in promoting bone differentiation. Methods: Enzyme solution was used to obtain newborn SD rats calvarial osteoblasts (ROB), which were processed by 50 Hz 0.6 mT PEMF for 0, 0.5, 1, 1.5 and 2 h, detecting PI3K and AKT protein expression and changes in primary cilia length and incidence;with LY294002 blocking PI3K/AKT signaling pathways we observed whether PEMF promoted osteogenic differentiation of ROB was affected;by interfering IFT88 gene expression by RNAi to inhibit primary cilia we observed whether PI3K/AKT signaling pathway and osteogenic differentiation of ROB was affected. Osteogenic differentiation indexes included alkaline phosphatase (ALP) activity, Real -time PCR and Western blot detection of osteogenic related genes of BMP-2, COL-1 and OSX and calcified nodules number, etc. Results: After exposure to PEMF for 0, 0.5, 1, 1.5, and 2 h, the protein expression of PI3K and AKT in ROB were increased significantly ( P <0.01) and the primary cilia became longer;and the protein expression of PI3K reached the highest level at 0.5 h, as the treatment time of PEMF increased, the PI3K protein expression decreased. AKT showed higher protein expression at 0.5 h and 1.5 h . After blocking the PI3K/AKT signaling pathway with the PI3K blocker LY294002, PEMF could no longer increase ALP activity and the gene expressions of BMP-2, COL-1, OSX which were osteogenically related. However, PEMF could increase the ALP activity and the osteogenically related gene expression in ROB before blocking. After RNAi interfered the primary cilia, PEMF could no longer increase the protein expression of PI3K, which indicated that PEMF could not activate the PI3K/AKT signaling pathway after primary cilia interfering;secondly, the effect of PEMF on enhancing ALP activity disappeared, it also decrease the gene expressions of BMP

关 键 词：脉冲电磁场 成骨细胞 RNA干扰 PI3K 

分 类 号：R336[医药卫生—人体生理学]