不同占空比低强度脉冲电磁场对大鼠成骨细胞的影响

Effects of Pulsed Electromagnetic Fields With Different Duty Circles on Osteoblast of Rat

目的:研究磁感应强度为1 mT、频率为15 Hz不同占空比的脉冲电磁场(pulsed electromagnetic fields,PEMFs)对体外培养大鼠成骨细胞增殖与细胞分化的影响。方法:取新生SD大鼠仔鼠头盖骨,用骨组织块培养法分离成骨细胞,培养至第3代后,分别对其进行场强1 mT、频率15 Hz,占空比10%、20%、40%、60%的脉冲电磁场作用,8 h/d,持续作用3d,应用MTT法、碱性磷酸酶测定检测成骨细胞增殖、分化情况。结果:不同占空比PEMFs对大鼠成骨细胞增殖与分化影响程度不同,20%、40%和60%占空比组显著提高成骨细胞增殖水平(P<0.05),其中40%和60%占空比组作用效果最显著(P<0.01)。10%、20%、40%和60%占空比组均能促进成骨细胞分化(P<0.05),其中以60%占空比组的效果最为明显(P<0.01)。结论:本研究进一步证实了低强度PEMFs能够促进成骨细胞的增殖与分化,并且PEMFs对成骨细胞的影响依赖于占空比参数的选择,而且有可能存在"占空比"窗口。

Objective： The present study aimed to systematically study the effects of pulsed electromagnetic fields （PEMFs, 1 mT, 15 Hz） with different duty circles （10%, 20%, 40% and 60%） on the osteoblastic activities, including cell proliferation and differentiation. Methods： The osteoblast-like cells were isolated from the tissue patch of the calvaria of newborn SD rats. Cells of the 3rd passage were exposed to PEMFs （1 mT, 15 Hz） with 10%, 20%, 40% and 60% duty circles at 8 hours daily, respectively. After 7 days, the osteoblastic proliferation and differentiation were respectively evaluated using MTT assay and determination of alkaline phosphatase （ALP） activities. Results： PEMFs with 20%, 40% and 60% duty circles significantly increased the cell proliferation （P〈 0.05）. Moreover, groups with 40% and 60% duty circles exhibited more obvious efficiency （P 〈 0.01）. PEMFs with 10%, 20%, 40% and 60% duty circles all dramatically accelerated the cellular differentiation （P 〈 0.05）. The effects were more obvious in the group with 60% duty circles （P 〈 0.01）. Conclusions： In agreement with previous studies, the present study proved that PEMFs with low intensity could stimulate the proliferation and differentiation of in vitro osteoblasts. We further demonstrated that the beneficial effects of PEMFs also relied on the selection of duty circles. It might exhibit potential ＇ duty circles window＇ for PEMFs on osteoblastic activities.