Scientists recently conducted a series of studies to test the biosafety and neurobehavioural effects of 33.0 Tesla high static magnetic fields (SMF) using the Steady High Magnetic Field Facility (SHMFF) biological research platform of their own design. The experiments were carried out by Prof. Xin Zhang’s team at the Hefei Institute of Physical Science of the Chinese Academy of Sciences.
They reported for the first time on the biosafety of 30 Tesla level SMF and the neurological effects of 20 Tesla and 30 Tesla level SMF on healthy mice in the Journal of Magnetic Resonance Imaging and European radiology.
In recent years, ultra-high field magnetic resonance imaging (MRI) has developed rapidly due to its significant advantage of high image resolution. 7 Tesla MRI has been clinically approved and 21.1 Tesla MRI has been used successfully in rodents. However, studies on the biosafety of high magnetic fields above 20 Tesla are still scarce, and relevant studies above 30 Tesla are still patchy.
Based on the previous biosafety study of 3.5-23.0 Tesla SMF, Xin Zhang’s group further increased the magnetic field strength and shortened the exposure time. Healthy C57BL/6J mice were exposed to 7.0-33.0 Tesla SMF for one hour.
After challenge, all mice were routinely fed for two months. Apart from some metabolic and liver and hepatorenal functional indicators affected by the magnetic field, the total blood count and the organ coefficient of the histomorphology of the main organs were not seriously affected. Most mice stayed within the normal reference range.
Meanwhile, behavioral tests showed that high SMF reduced anxiety and improved social and spatial memory in mice within two months of exposure.
Additionally, Behavioral studies in healthy mice exposed to a magnetic field of 3.5 to 23.0 Tesla for two hours also revealed improved neurocognitive effects, possibly associated with increased calcium/calmodulin-dependent protein kinase II expression in the mouse hippocampus.
Zhang’s group further found that 7 Tesla SMF was effective in relieving the symptoms of depressed mice. These results not only provide useful safety information for the development of ultra-high MRI, but may also suggest that high SMF has the potential to be a future antidepressant treatment.
References: “Short- and long-term effects of 3.5–23.0 Tesla ultra-high magnetic fields on mice behavior” by Md Hasanuzzaman Khan, Xinfeng Huang, Xiaofei Tian, Changjie Ouyang, Dongmei Wang, Shuang Feng, Jutao Chen, Tian Xue, Jin Bao and Xin Zhang, March 16, 2022, European Radiology.
This study was supported by the National Key Research & Development Program of the Ministry of Science and Technology, the National Natural Science Foundation of China, the President’s Fund of Hefei Institutes of Physical Science, etc.