The aim of present study was to determine the effect of
estrogen treatment on blood-brain barrier permeability in rats with induced global
cerebral ischemia. The study included six-month-old female Sprague-Dawley rats which were divided into the following groups: Control-
Ischemia-Reperfusion (C + I-R);
Ovariectomy-
Ischemia-Reperfusion (Ovx + I-R);
Ovariectomy +
Estrogen +
Ischemia-Reperfusion (Ovx + E + I-R);
Ovariectomy +
Ischemia-Reperfusion +
Estrogen (Ovx + I-R + E).
Ischemia-reperfusion was induced by clamping two carotid arteries, then opening the clamp. Blood-brain barrier permeability was visualized by
Evans Blue extravasation and quantified by spectrophotometry. Our results indicate that following
ischemia-reperfusion the BBB permeability is increased in ovariectomized rats (
Evans Blue extravasation) compared to the control group in the cortex, thalamus, hippocampus, cerebellum and brain stem, while in the midbrain no significant increase was detected. In contrast, BBB permeability in the groups treated with
estrogen, administered either before or after
ischemia-reperfusion, was significantly lower than in ovariectomized animals. In conclusion, the increase in BBB permeability resulting from experimentally induced
cerebral ischemia was prevented by exogenous
estrogen treatment. The study results indicate that
estrogen may be used for therapeutic purposes in
ischemia-reperfusion.