ABSTRACT
Objective To estimate any influence of strong pulsed magnetic fields on the expression of growth-related genes in human bladder cancer BIU-87 cells. Methods Human BIU-87 cells were cultured in vitro and randomly divided into a magnetic field group and a control group. Each group was further divided into 24 h, 48 h and 72 h sub-groups. The magnetic field group cells were exposed to an 8 T magnetic field pulsed at 15 Hz for 2 h every day. The control group cells also placed on the same environment, but not exposed to any strong, pulsed magnetic field. The expression of B cell lymphoma/leukemia gene-2 (Bcl-2) mRNA, Bax mRNA and caspase-3 mRNA was measured with RT-PCR, and flow cytometry was used to evaluate the expression of the Bcl-2, Bax and caspase-3 genes of the tumor cells in vitro. Results The expression of Bax mRNA and protein was significantly higher in the cells exposed to the magnetic field than in the control groups. The expression of Bcl-2 mRNA and protein was significantly less. The expression of caspase-3 mRNA and protein in the two groups showed no significant differences.Conclusions A strong, pulsed magnetic field can inhibit the growth of bladder tumor BIU-87 cells and promote their apoptosis. The mechanism is probably related with the magnetic field promoting Bax mRNA and protein expression and inhibiting Bcl-2 mRNA and protein expression.
ABSTRACT
Objective To investigate the effects of low frequency pulsed magnetic fields (LF-PMFs) on proliferation, the cell cycle, apoptosis, migration, cytoskeleton formation and nitric oxide (NO) secretion in cardiac microvascular endothelial cells (CMECs). Methods LF-PMFs with rectangular and triangular waveforms at 15 Hz were tested. The CMECs were randomly divided into a control group, 0.6 mT group, 1.2 mT group, 1.8 mT group and 2.4 mT group. Except for the control group, the CMECs were exposed to LF-PMFs 4 h/day for 5 days. Results After 5 days of intervention with rectangular wave LF-PMFs the proliferation of CMECs accelerated and NO secretion was enhanced significantly. The percentages of cells at ( S+G2 ) phase increased significantly, whereas apoptosis rates were significantly lower than in the control group. The migration of CMECs was facilitated, stress fibers increased and cytoskeleton components were reorganized. After 5 days of intervention with triangular wave LF-PMFs proliferation of CMECs accelerated and NO secretion was significantly enhanced. The percentages of cells at(S+G2)phase and migration increased, while apoptosis was inhibited. Cytoskeleton components were reorganized after exposure to 0.6 mT and 2.4 mT triangular waveform LF-PMFs. No significant change was detected with 1.2 mT and 1.8 mT triangular waveform LF-PMFs with regard to these variables. Conclusions The effects of LF-PMFs on proliferation, the cell cycle, apoptosis, migration, cytoskeleton formation and NO secretion function of CMECs were infiuenced by the waveform in addition to it's intensity and frequency.
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Objective To investigate the effects of pulsed magnetic fields of different intensity on carotid restenosis (CRS), post carotid endarterectomy (CEA) and the expression of matrix metalloproteinase-2 (MMP-2)in vascular smooth muscle cells (VSMC). Methods An animal model of carotid altherosclerosis was established in 50 New Zealand rabbits by using air-drying lesions combined with high fat feed. After two months, the rabbits were treated with bilateral CEA, and then divided randomly into 3 groups. Two of the groups were treated with ei-ther 0.6 or 1.0 T pulsed magnetic fields, while the third group served as an untreated blank control. Changes in the pathology of the tunica intima were observed 1, 2 and 3 months after the CEA using morphologic analysis, and the expression of MMP-2 in the VSMC was determined using immunohistochemistry. Results The histological a-nalysis showed that the total luminal area, plaque area, the maximum plaque thickness and the proportion of siena-sis in the treated groups were all significandy lower, on average, than in the control group. At all three time points the average improvements in the 1.0 T group were significantly greater than in the 0.6 T group. The average ex-pression of MMP-2 in the treated groups was significantly lower than in the control group, especially in the 1.0 T group. Conclusions Pulsed magnetic field therapy positively influences CRS and the expression of MMP-2 in VSMC. Reduced MMP-2 expression might be one of the mechanisms through which pulsed magnetic fields prevent or lessen carotid restenosis post CEA.
ABSTRACT
In this paper,a pulsed magnetic fields stimulation instrument is designed and realized,which provides a pulsed magnetic field with the range of maximal intensity from 0.01~2T,frequency from 0.2~100Hz and time width of pulse from 0.01~1ms.The instrument,controlled by the hand,foot or itself,can display stimulus intensity and times and output trigger signals with different waveforms to make measuring devices operate synchronistically.