Biological effects on cells in strong static magnetic field

Abstract

With the development of technology and the widespread use of high static magnetic fields (SMFs) in medical diagnosis, such as MRI (magnetic resonance imaging) in hospitals, patients have more and more chances to encounter high SMFs (higher than 1 T), which invokes increasing public concerns about human health. However, due to the experimental limitations, there are very few studies of high SMFs (above 1 T) on animals and human bodies. In contrast, cell, as a basic unit of various organisms, is the primary research target for most researches of the biological effects under the action of magnetic fields. However, due to the differences in magnetic field parameter, exposure condition and cell type, there are diverse experimental outcomes reported by individual studies in the literature. Here in this review, we summarize the results about the cellular effects under SMFs above 1 T, including changes of cell orientation, cell proliferation, microtubule and mitotic spindle orientation, DNA and cell cycle. Moreover, we also compare and analyze the factors that could cause these experimental variations, including the differential effects of high SMFs on cell type, such as cancer and non-cancer cells, as well as magnetic field intensity-induced experimental variations. The most well studied cellular effects are SMF-induced cell and polymer orientation changes, and the cellular composition is a key factor that determines the exact orientation of a cell in an SMF. For example, the normal red blood cell is aligned parallelly to the SMF direction, but the whole bull sperm is aligned perpendicularly to the SMF direction. Among the magnetic field parameters, the magnetic field intensity is especially critical. The red blood cells can only be partially aligned by 1 T SMF, but an 8 T SMF could align the red blood cells 100% along the magnetic direction. Overall, the biological research of high SMFs above 1 T, especially above 10 T, is still at an initial stage. Biological experiments in high SMFs above 20 T are especially lacking. This review could help provide some biological bases for future high SMF investigations, which is important not only for the basic understanding of the biological effects of high SMFs, but also for the applications of high SMFs in medicine, such as high field MRI.