[Effects of electromagnetic pulse on blood-brain barrier permeability and tight junction proteins in rats].
OBJECTIVE
To study the effect of electromagnetic pulse (EMP) on the permeability of blood-brain barrier, tight junction (TJ)-associated protein expression and localization in rats.


METHODS
66 male SD rats, weighing (200 approximately 250) g, were sham or whole-body exposed to EMP at 200 kV/m for 200 pulses. The repetition rate was 1 Hz. The permeability of the blood-brain barrier in rats was assessed by albumin immunohistochemistry. The expression of typical tight junction protein ZO-1 and occludin in both cerebral cortex homogenate and cerebral cortex microvessel homogenate was analyzed by the Western blotting and the distribution of ZO-1 and occludin was examined by immunofluorescence microscopy.


RESULTS
In the sham exposure rats, no brain capillaries showed albumin leakage, at 0.5 h after 200 kV/m EMP exposure for 200 pulses; a few brain capillaries with extravasated serum albumin was found, with the time extended, the number of brain capillaries with extravasated serum albumin increased, and reached the peak at 3 h, then began to recover at 6 h. In addition, no change in the distribution of the occludin was found after EMP exposure. Total occludin expression had no significant change compared with the control. However, the expression level of ZO-1 significantly decreased at 1 h and 3 h after EMP exposure in both cerebral cortex homogenate and cerebral cortex microvessel homogenate. Furthermore, immunofluorescence studies also showed alterations in ZO-1 protein localization in cerebral cortex microvessel.


CONCLUSIONS
The EMP exposure (200 kV/m, 200 pulses) could increase blood-brain barrier permeability in rat, and this change is associated with specific alterations in tight junction protein ZO-1.
Department of Radiation Medicine, Faculty of Preventive Medicine, Fourth Military Medical University, Xi'an 710032, China.
Lian-bo
LB
Qiu
Gui-rong
GR
Ding
Ya-mei
YM
Zhang
Yan
Y
Zhou
Xiao-wu
XW
Wang
Kang-chu
KC
Li
Sheng-long
SL
Xu
Juan
J
Tan
Jia-xing
JX
Zhou
Guo-zhen
GZ
Guo
D000818:Animals; D001812:Blood-Brain Barrier / Q000528:radiation effects*; D001921:Brain / Q000378:metabolism; D002199:Capillary Permeability / Q000528:radiation effects*; D004574:Electromagnetic Fields / Q000009:adverse effects*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D062826:Zonula Occludens-1 Protein
D008565:Membrane Proteins; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein