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Objective: To investigate the expression of occludin, ZO-1, MMP-2, and MMP-9 in cerebral microvasculature following Pulse Electromagnetic Field (PEMF) induced BBB permeability change., Methods: Sprague-Dawley rats were randomized into PEMF and sham exposed groups (n = 8). After exposure to PEMF at 0.5, 1, 3, 6, and 12 h, BBB permeability was measured by Evans-Blue extravasation. The expression of occludin, ZO-1, MMP-2, and MMP-9 were detected by real-time quantitative reverse transcriptase PCR and western blotting. MMP-2 and MMP-9 activity were detected by EnzChek gelatinase assay., Results: Compared with the sham group, PEMF exposure led to increased permeability of the BBB to EB, which was prolonged after exposure. BBB permeability became progressively more severe, and recovered at 6 h. The gene and protein expression of occludin and ZO-1 were significantly decreased, while MMP-2 and MMP-9 expression were significantly increased after exposure to PEMF. All levels of expression recovered 12 h following PEMF., Conclusion: Changes to BBB permeability were related to the alteration expression of tight junction proteins and matrix metalloproteinase after exposure to PEMF.

Objective: To investigate and compare the effect of radio-frequency (RF) field exposure on expression of heat shock proteins (Hsps) in three human glioma cell lines (MO54, A172, and T98)., Methods: Cells were exposed to sham or 1950 MHz continuous-wave for 1 h. Specific absorption rates (SARs) were 1 and 10 W/kg. Localization and expression of Hsp27 and phosphorylated Hsp27 ((78) Ser) (p-Hsp27) were examined by immunocytochemistry. Expression levels of Hsp27, p-Hs27, and Hsp70 were determined by Western blotting., Results: The Hsp27 was primarily located within the cytoplasm, p-Hsp27 in both cytoplasm and nuclei of MO54, A172, and T98 cells. RF field exposure did not affect the distribution or expression of Hsp27. In addition, Western blotting showed no significant differences in protein expression of Hsp27 or Hsp70 between sham- and RF field-exposed cells at a SAR of 1 W/kg and 10 W/kg for 1 h in three cells lines. Exposure to RF field at a SAR of 10 W/kg for 1 h slightly decreased the protein level of phosphorylated Hsp27 in MO54 cells., Conclusion: The 1950 MHz RF field has only little or no apparent effect on Hsp70 and Hsp27 expression in MO54, A172, and T98 cells.

Objective: To observe the effect of electromagnetic pulse (EMP) exposure on cerebral micro vascular permeability in rats., Methods: The whole-body of male Sprague-Dawley rats were exposed or sham exposed to 200 pulses or 400 pulses (1 Hz) of EMP at 200 kV/m. At 0.5, 1, 3, 6, and 12 h after EMP exposure, the permeability of cerebral micro vascular was detected by transmission electron microscopy and immunohistochemistry using lanthanum nitrate and endogenous albumin as vascular tracers, respectively., Results: The lanthanum nitrate tracer was limited to the micro vascular lumen with no lanthanum nitrate or albumin tracer extravasation in control rat brain. After EMP exposure, the lanthanum nitrate ions reached the tight junction, basal lamina and pericapillary tissue. Similarly, the albumin immunopositive staining was identified in pericapillary tissue. The changes in brain micro vascular permeability were transient, the leakage of micro vascular vessels appeared at 1 h, and reached its peak at 3 h, and nearly recovered at 12 h, after EMP exposure. In addition, the leakage of micro vascular was more obvious after exposure of EMP at 400 pulses than after exposure of EMP at 200 pulses., Conclusion: Exposure to 200 and 400 pulses (1 Hz) of EMP at 200 kV/m can increase cerebral micro vascular permeability in rats, which is recoverable.