Altered expression of matrix metalloproteinases and tight junction proteins in rats following PEMF-induced BBB permeability change

Biomed Environ Sci. 2012 Apr;25(2):197-202. doi: 10.3967/0895-3988.2012.02.011.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood-Brain Barrier*
  • Electromagnetic Fields*
  • Male
  • Matrix Metalloproteinases / metabolism*
  • Proteins / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Tight Junctions / metabolism*


  • Proteins
  • Matrix Metalloproteinases