The Weak Combined Magnetic Fields Reduce the Brain β-Amyloid in an Animal Model of Sporadic Alzheimer's Disease

Subchronic effect of weak combined magnetic fields (MFs) on spatial memory and level of brain beta-amyloid (beta A) was studied in mice with ablation of the olfactory bulbs and control sham-operated (SO) animals. The bulbectomized (BE) mice show the main signs of Alzheimer's type degeneration such as memory impairment, the increase of the beta A level in the brain, pathology in the acetylcholinergic system, and the loss of neurons in the brain structures responsible for memory [5-7,9]. The combined MFs consisted of the constant component 42 mu T and of the variable component 0.08 mu T The variable field was the sum of two signals of frequencies of 4.38 and 4.88 Hz. Exposure to the MFs (4 hours for 10 days) induced the reduction of the beta A level in the brain of the BE mice, but did not protected their memory from impairment. However, the same MFs improved the spatial memory in SO mice. The beneficial effect of the MFs in the SO animals was prolonged and was revealed for a month after exposure to the MFs. The results suggest that the MFs can be used to prevent the Alzheimer's disease in a group of risk as well as in other diseases involving amyloid protein deposition in different tissues.