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Postischemic estrogen reduces hypoperfusion and secondary ischemia after experimental stroke
L D McCullough1, N J Alkayed, R J Traystman
1Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287-4961, USA.
Stroke
|March 10, 2001
Summary
Acute estrogen therapy during reperfusion significantly reduces brain damage in experimental stroke by rapidly improving cerebral blood flow (CBF) and decreasing no-reflow zones.
Area of Science:
- Neuroscience
- Vascular Biology
- Pharmacology
Background:
- Estrogen demonstrates neuroprotective and vasoprotective properties in experimental cerebral ischemia.
- Preischemic steroid administration protects both male and female animals from focal cerebral ischemia.
Purpose of the Study:
- To investigate if intravenous estrogen administered during reperfusion acts as a vasodilator.
- To determine if estrogen-induced increase in cerebral blood flow (CBF) offers tissue protection against middle cerebral artery occlusion.
Main Methods:
- Adult male Wistar rats underwent 2-hour middle cerebral artery occlusion, followed by intravenous estrogen or vehicle infusion during reperfusion.
- Cortical laser-Doppler flowmetry assessed occlusion adequacy.
- Ischemic lesion volume was quantified at 22 hours; CBF was measured via autoradiography at 10 and 90 minutes of reperfusion.
Main Results:
- Estrogen treatment significantly reduced total hemispheric infarction, particularly in the striatum.
- Estrogen infusion markedly increased CBF recovery at 10 minutes in the frontal cortex, parietal cortex, and striatum.
- The volume of brain tissue with low CBF recovery was substantially smaller in estrogen-treated rats.
Conclusions:
- Acute estrogen therapy during reperfusion improves outcomes in experimental stroke.
- Estrogen rapidly enhances CBF recovery and reduces no-reflow areas in the brain.
- The beneficial effects of estrogen are observed during early reperfusion and may complement other neuroprotective mechanisms.