The Biological Effect Of Static Magnetic Field On Cultured Maxillofacial Skeletal Muscle Cells In Vitro

Objectives: The purpose of this study was to observe the biological effects of static magnetic field(SMF)at 971.77mT produced by the rare earth magnets used in orthodontics on cultured maxillofacial skeletal muscle cells, and to discuss the biological effects of the static magnetic field on the remodeling of maxillofacial skeletal muscle tissues during the orthodontics treatment.Materials and Methods: the maxillofacial skeletal muscle cells were isolated and cultured in vitro from the neonatal Sprague-Dawley rat, the cultured SD maxillofacial skeletal muscle cells of the third generation were treated with SMF for seven days. Cell counting to draw a growth curve ,and calculate the doubling time of maxillofacial skeletal muscle cell; by scanning transmission electron microscopy(TEM) to observe the ultrastructural change of the cell; the method of MTT was employed to evaluate the level of proliferation ,the parameters regarding the variation of the cell cycle were detected with the flow cytometry (FCM). Result: after the treatment with SMF for seven days, the growth curve show that the cells which under the SMF have a well adaptability , as compare to the control group and the blank group ,the number of the maxillofacial skeletal muscle cells exposed to 971.77mT SMF was significantly higher at the same day(P< 0.001), there was no difference between the control group and the blank group, for the doubling time of maxillofacial skeletal muscle cell, the experimental group was more early than the control group and the blank group; by scanning TEM ,there was no pathologisch changes of the morphocytology from the experimental group and the blank group ,but the experimental group has more activate free ribosomes, glycogen, Golgi apparatus, bioblast, rough endoplasmic reticulum and microfilament compare to the blank group; the amount of cells proliferation determined by MTT after cultured for 48hrs and 72hrs , the proliferative rate of the experimental group was significantly higher than the blank group .Conclusion: SD maxillofacial skeletal muscle cells which under the SMF have a well adaptability; and there is no pathologisch changes to the morphocytology of the cells , the rare earth magnet is safe to use in the orthodontics ; also the SMF has the function to enhance the proliferation.