Effects of high and low 17β-estradiol doses on cerebral ischemia
(English)Manuscript (preprint) (Other academic)
INTRODUCTION: Estrogens’ effects on cerebral ischemia have during the last two decades been the subject of intense research efforts. Notwithstanding this, the reasons that some studies indicate that estrogens are damaging while others show estrogen-induced neuroprotection has hitherto not been fully elucidated. Recent evidence indicates that discrepancies in hormone administration paradigms, resulting in highly different serum hormone concentrations, may account for this dichotomy. The current study was designed to test this ypothesis.
METHODS: Sixty ovariectomized female rats were randomized into three groups differing in subsequent 17β-estradiol regimen (vehicle, low dose and high dose respectively). Following two weeks of treatment, focal cerebral ischemia was induced via an intraluminal filament middle cerebral artery occlusion (MCAo) method. All animals were subjected to a small functional testing battery, and three days after MCAo they were sacrificed for infarct size assessment.
RESULTS AND DISCUSSION: The hormone administration regimens significantly affected animal weights and feeding behavior, but infarct sizes did not differ between groups. Further, random intra-group variations in infarct size were too large to allow negative conclusions to be drawn. The large variation was possibly a consequence of too large occluding filament diameter in combination with that the animals were allowed to wake up during ongoing MCAo. After correcting the large variation, the hypothesis needs to be addressed anew.
Administration methods, Cerebral ischemia, Elevated body swing test, Estrogens, Hormesis, Silastic capsules, Slow-release pellets
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:liu:diva-77192OAI: oai:DiVA.org:liu-77192DiVA: diva2:525443