Author: Zhu BY1,2, Yang ZD3, Chen XR4, Zhou J2, Gao YH2, Xian CJ5, Chen KM6
Affiliation: <sup>1</sup>School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050, People's Republic of China.
<sup>2</sup>Institute of Orthopaedics, Lanzhou General Hospital of CPLA, Lanzhou, 730050, People's Republic of China.
<sup>3</sup>School of Life Science and Engineering, Lanzhou University of Technology, Lanzhou, 730050, People's Republic of China. yangzhongduo@126.com.
<sup>4</sup>College of Life Sciences, Northwest A & F University, Yanglin, 712100, People's Republic of China.
<sup>5</sup>Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA, 5001, Australia.
<sup>6</sup>Institute of Orthopaedics, Lanzhou General Hospital of CPLA, Lanzhou, 730050, People's Republic of China. chenkm@lut.cn.
Conference/Journal: Calcif Tissue Int.
Date published: 2018 Jan 23
Other:
Special Notes: doi: 10.1007/s00223-018-0396-2. [Epub ahead of print] , Word Count: 242
We proposed a three-step strategy to obtain the optimal therapeutic parameters, which is composed of large-scale screening at cellular level, verification in animal experiments, and confirmation by a clinical trial. The objective of the current study was to test the feasibility of our strategy. Newborn rat calvarial osteoblasts were treated by 50 Hz 1.8 mT sinusoidal electromagnetic fields (SEMFs) with 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 h/days, respectively. The osteogenic differentiation and maturation of the osteoblast were assayed and compared to obtain the optimal duration. One-month-old growing rats were then treated by the same SEMFs with 0.5, 1.5, and 2.5 h/days, respectively, and the peak bone mass was analyzed after 2 months. It was found that the optimal exposure duration to promote the osteogenic differentiation and maturation of osteoblasts was 1.5 h/days, judging by the increasing degrees of ALP activity, calcified nodules formed, the gene and protein expression levels of Runx-2, BMP-2, and Col-I, as well as the expression levels of signaling proteins of the BMP-2/Smad1/5/8 pathway. The highest increase of peak bone mass after 2 months was also obtained by 1.5 h/days, judging by the results of X-ray dual-energy absorptiometry, mechanical property analysis, micro-CT scanning, and serum bone turnover marker examinations. The above results indicated that exposure duration is a determinant for the therapeutic effect of EMFs, and the optimal therapeutic effects only can be obtained by the optimal exposure duration.
KEYWORDS: Bone mineral density; Exposure duration; Osteoblasts; Peak bone mass; Sinusoidal electromagnetic fields
PMID: 29362823 DOI: 10.1007/s00223-018-0396-2