Effects of electromagnetic pulse exposure on gelatinase of blood-brain barrier in vitro

High-Power Electromagnetic Pulse Exposure of Healthy Mice: Assessment of Effects on Mice Cognitions, Neuronal Activities, and Hippocampal Structures

Electromagnetic pulse (EMP) is a high-energy pulse with an extremely rapid rise time and a broad bandwidth. The brain is a target organ sensitive to electromagnetic radiation (EMR), the biological effects and related mechanisms of EMPs on the brain remain unclear. The objectives of the study were to assess the effects of EMP exposure on mouse cognitions, and the neuronal calcium activities in vivo under different cases of real-time exposure and post exposure. EMP-treated animal model was established by exposing male adult C57BL/6N mice to 300 kV/m EMPs. First, the effects of EMPs on the cognitions, including the spatial learning and memory, avoidance learning and memory, novelty-seeking behavior, and anxiety, were assessed by multiple behavioral experiments. Then, the changes in the neuronal activities of the hippocampal CA1 area in vivo were detected by fiber photometry in both cases of during real-time EMP radiation and post-exposure. Finally, the structures of neurons in hippocampi were observed by optical microscope and transmission electron microscope. We found that EMPs under this condition caused a decline in the spatial learning and memory ability in mice, but no effects on the avoidance learning and memory, novelty-seeking behavior, and anxiety. The neuron activities of hippocampal CA1 were disturbed by EMP exposure, which were inhibited during EMP exposure, but activated immediately after exposure end. Additionally, the CA1 neuron activities, when mice entered the central area in an Open field (OF) test or explored the novelty in a Novel object exploration (NOE) test, were inhibited on day 1 and day 7 after radiation. Besides, damaged structures in hippocampal neurons were observed after EMP radiation. In conclusion, EMP radiation impaired the spatial learning and memory ability and disturbed the neuronal activities in hippocampal CA1 in mice.

Effect of ultra‑wide‑band electromagnetic pulses on blood‑brain barrier permeability in rats

The restrictive nature of the blood brain barrier (BBB) brings a particular challenge to the treatment of central nervous system (CNS) disorders. The effect of ultra-wide band electromagnetic pulses (UWB-EMPs) on BBB permeability was examined in the present study in order to develop a safe and effective technology that opens the BBB to improve treatment options for CNS diseases. Rats were exposed to a single UWB-EMP at various field strengths (50, 200 or 400 kV/m) and the BBB was examined using albumin immunohistochemistry and Evans blue staining at different time periods (0.5, 3, 6 and 24 h) after exposure. The expression and distribution of zonula occludens 1 (ZO-1) were evaluated using western blotting to identify a potential mechanism underlying BBB permeability. The results showed that the BBB permeability of rats exposed to UWB-EMP increased immediately following UWM-EMP treatment and peaked between 3 and 6 h after UWB-EMP exposure, returning to pre-exposure levels 24 h later. The data suggested that UWB-EMP at 200 and 400 kV/m could induce BBB opening, while 50 kV/m UWB-EMP could not. The levels of ZO-1 in the cerebral cortex were significantly decreased at 3 and 6 h after exposure; however, no change was observed in the distribution of ZO-1. The present study indicated that UWB-EMP-induced BBB opening was field strength-dependent and reversible. Decreased expression of ZO-1 may be involved in the effect of UWB-EMP on BBB permeability.