Electromagnetic Pulse Alter Permeability of the Blood-brain Barrier in Rats

The effect of electromagnetic pulse (EMP) exposure on blood-brain barrier (BBB) permeability in rat brain after whole-body exposed or sham exposed to EMP at 200 kV/m for 400 pulses (1 Hz) was investigated. At 1, 3 and 6 h after EMP exposure, disruption of BBB integrity in rat frontal cerebral cortex was detected by transmission electron microscopy and immunohistochemistry using lanthanum. nitrate and endogenous albumin as vascular tracers respectively. The results showed that in control rat brain, lanthanum. nitrate tracer was limited to the capillary lumen, no lanthanum nitrate and albumin tracer extravasation was found. After EMP exposure, lanthanum nitrate ions reached the tight junction, basal lamina and the pericapillary tissue. Similarly, albumin immunopositive staining was also found in the pericapillary tissue. The changes of BBB permeability were transient, the leakage of BBB was found at 1 h, and reach the peak at 3 h, then began to recover at 6 h after EMP exposure. These results suggest that exposure to EMP at 200 kV/m for 400 pulses (1 Hz) could increase the permeability of BBB in rat frontal cerebral cortex and this change is recoverable.