Medical/biological study (experimental study)

Altered Expression of Matrix Metalloproteinases and Tight Junction Proteins in Rats following PEMF-Induced BBB Permeability Change med./bio.

By: Zhang YM, Zhou Y, Qiu LB, Ding GR, Pang XF

Published in: Biomed Environ Sci 2012; 25 (2): 197-202

Protein expression and corresponding gene expression of occludin, ZO-1 and two metalloproteinases as well as the enzyme activity of the metalloproteinases were examined. Occludin is a transmembrane protein that restricts the permeability at the tight junctions. ZO-1 links transmembrane proteins to the actin cytoskeleton. A disruption of these combinations as well as an increased enzyme activity of metalloproteinases are associated with an increased permeability of the blood brain barrier.
Rats were sham exposed or exposed and analyzed 0.5, 1, 3, 6 or 12 hours post exposure (n=8 per group).

Exposure	Parameters
Exposure 1: unspecified Exposure duration: 200 seconds	electric field strength: 200 kV/m

Frequency	unspecified
Waveform	pulsed
Exposure duration	200 seconds
Additional info	3.5 ns rising time, 14 ns pulse width, amplitude up to 200 kV, 1 Hz repetition rate

Sham exposure	A sham exposure was conducted.

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	200 kV/m	-	-	-	-

Exposed system:

Investigated system:

Time of investigation:

The permeability of the blood brain barrier was significantly increased 0.5, 1 and 3 hours after exposure when compared to the sham exposed group. After exposure, protein expression and gene expression of occludin and ZO-1 were significantly decreased compared to the control group, while the expression of the metalloproteinases was significantly increased. Additionally, the enzyme activity of the metalloproteinases was significantly increased compared to the sham exposed group.
12 hours after the exposure, the values recovered and no changes in the permeability, protein expression, gene expression and enzyme activity were observed in comparison to the sham exposed group.
The authors conclude that PEMF exposure could transiently alter the permeabilty of the blood brain barrier and that this effect was related to modified expression levels of occludin, ZO-1 and metalloproteinases.

Study character:

Zhou JX et al. (2013): Detrimental effect of electromagnetic pulse exposure on permeability of in vitro blood-brain-barrier model
Qiu LB et al. (2011): Synthetic gelatinases inhibitor attenuates electromagnetic pulse-induced blood-brain barrier disruption by inhibiting gelatinases-mediated ZO-1 degradation in rats
Gulturk S et al. (2010): Effect of exposure to 50 Hz magnetic field with or without insulin on blood-brain barrier permeability in streptozotocin-induced diabetic rats
Ding GR et al. (2010): EMP-induced alterations of tight junction protein expression and disruption of the blood-brain barrier
Ding GR et al. (2009): Effect of electromagnetic pulse exposure on brain micro vascular permeability in rats
Ding G et al. (2009): Electromagnetic Pulse Alter Permeability of the Blood-brain Barrier in Rats
Nittby H et al. (2008): Radiofrequency and extremely low-frequency electromagnetic field effects on the blood-brain barrier
Persson BR et al. (1992): Increased permeability of the blood-brain barrier induced by magnetic and electromagnetic fields
Ravnborg M et al. (1990): No effect of pulsed magnetic stimulation on the blood-brain barrier in rats