Effect of Magnetic Fields on Osteoblasts and Fibroblasts in vitro

Fukuzawa R.^*, Ozawa S.^*, Maeda H.^**, Kubo K.^**, Sugita Y.^**, Yoshida W.^**, Tanaka Y.^*

^*Department of Removable Prosthodontics, School of Dentistry, Aichi-Gakuin University

^**Department of Oral Pathology, School of Dentistry, Aichi-Gakuin University

Abstract

Purpose

The purpose of this study is to compare osteoblasts which are responsible to bone formation with fibroblasts which do not make bone, and explore a mechanism of accelerated bone formation by the magnetic field exposure.

Materials and methods

In this study MC3T3-E1 cells that are established osteoblast cell strain form mouse calvaria and L929 that is standard fibroblast cell strain were used. A strength and frequency of extremely low magnetic fields (ELMF) was set to 0.4T and 0.17 Hz respectively, and the ELMF was exposed to semi-confluent culture plates for 6 hours.

Cell proliferation was assessed by using a colorimetric proliferation assay after ELMF exposure. Alkaline phosphatase (ALP) activities of MC3T3-E1 cells were measured after ELMF exposure to evaluate osteoblast differentiation.

Results

Proliferation of MC3T3-E1 cells were promoted at day 3 after ELMF exposure. On the proliferation of L929 cells, the exposed culture did not show any differences at any time points compared with the control cultures. ALP activity in MC3T3-E1 cell significantly increased at day 7 and day10 as compared with the controls.

Conclusion

ELMF of 0.4T and 0.17Hz stimulated mouse osteoblast-like cell proliferation at early stage, and differentiation to mature osteoblasts, whereas fibroblasts did not show significant differences in proliferation by the exposure.