目的:弱强度的低频电磁场可促进成骨细胞的增殖、分化和钙盐分泌,进而加速伤骨愈合、加快骨组织代谢,为揭示低频弱脉冲电磁场影响成骨细胞的初始效应,应用表面增强拉曼光谱技术探索电磁场对成骨细胞的作用机制。方法:用出生5d的Wistar品系小鼠的颅骨接种成骨细胞并传代。应用表面增强拉曼光谱技术实时的方法采集不同磁场作用时间内低频率(50Hz)、低强度(0.30mT)脉冲电磁场作用下的成骨细胞的拉曼光谱。每隔1min采集一次,至作用8min止;并与电磁场作用前采集的拉曼光谱做比对。结果:比较电磁场作用前后和作用8min内不同时刻的拉曼光谱,可知其对成骨细胞膜蛋白和磷脂分子的构象有一定影响:表征膜蛋白中氨基酸侧链和磷脂C-C键骨架的特征峰的位移只发生了小幅变化,说明实验电磁场对细胞膜无损伤作用;在其作用之初的4.0~5.0min内,表征蛋白质构象信息的6个拉曼特征峰的相对强度随时间逐渐增加,揭示了构象发生改变的膜蛋白数量随电磁场作用时间的延长而增多。结论:实验探测到成骨细胞对低频脉冲电磁场的最初响应机制,表现为膜蛋白构象的有序变化。这为进一步探索由电磁刺激而激活的成骨细胞一系列信号转导通路的上游机制提供了有力的依据。
AIM: It is reported that pulsed electromagnetic fields with low frequency and amplitude could induce osteoblasts to proliferate, differentiate and deposit calcium salts, which consequently, accelerate the healing and metabolism of injured bone. In this study, the original effect of the pulsed electromagnetic fields with low frequency and amplitude on osteoblasts was revealed by exploring the mechanism of the interaction between them with Raman spectra. METHODS: The osteoblasts from cranial bones of 5-day-old Wistar mice were seeded and passaged. The Raman spectra of osteoblasts were obtained in real-time by applying the technique of surface-enhanced Raman spectra pulsed electromagnetic field (50 Hz, 0.3 mT). The spectra were collected every one minute in the electromagnetic fields within 8 minutes. The result was compared with the spectra gained before applying the fields. RESULTS: The comparison revealed that the conformation of membrane proteins and phospholipids at different time in the electromagnetic fields was changed by analyzing the spectra. The fields presented no damage to the celt membrane judging from the tiny changes of the wavelengths of the spectra that indicated the side chains of amino acids and carbon skeletons of phospholipids. There were six characteristic peaks of proteins whose relative intensities increased gradually, showing that the amount of the membrane proteins with changed conformations was increased as time went on in the electromagnetic fields in the earlier 4 or 5 minutes. CONCLUSION: The findings suggest that the original response mechanism of osteoblasts against electromagnetic fields is the conformational changes of membrane proteins, which provides the convincing basis for the research on the initial mechanism of several signal transductions in osteoblasts generated by the electromagnetic stimulation.