Abstract

In order to elucidate the biological effects of pulsating magnetic field in in vitro culture system we designed a pulsating magnetic apparatus using 120 Hertz, 24 Volt direct current. It can generate 63~225 Gauss in the experimental area of 90 mm petri dish, and has little thermal effect on the culture media in 37.5oC, 5% CO2. Human osteogenic sarcoma (HOS) cells were cultured in the pulsating magnetic field and the nuclear changes of cultured cells were observed routinely by hematoxylin staining, and apoptotic change was detected by ApopTag staining using both peroxidase and fluorescein labelings. Compared to the control group which formed well organized whorling pattern of HOS cell line in 3 days culture, the HOS cells cultured in the pulsating magnetic field for 12 hours or 24 hours grew irregularly and showed increased number of apoptotic cells. When the flow of pulsating magnetic field was interrupted by insertion of strong permanent magnetic bar (1000 Gauss, 5530 mm) beneath the petri dish during in vitro culture, the area of sparse pulsating magnetic field showed active proliferation and aggregation of HOS cells even in 24 hour exposure group. These data suggest that the pulsating magnetic field may play a role in inducing growth retardation and apoptosis of HOS cells. Furthermore, the hazardous effects of pulsating magnetic field can be lessened or nullified by the interruption of pulsating magnetic field with a strong permanent magnetic bar.

• Keywords: Pulsating magnetic field;Apoptosis;HOS cell