The loss of estrogen efficacy against cerebral ischemia in aged postmenopausal female mice

Publication date: 13 January 2014 Source:Neuroscience Letters, Volume 558 Author(s): Min Cai , Yu-Long Ma , Pei Qin , Yan Li , Li-Xia Zhang , Huang Nie , Zhengwu Peng , Hui Dong , Hai-Long Dong , Wu-Gang Hou , Li-Ze Xiong Estrogen has been shown to have neuroprotective effects in numerous experimental studies involving young and adult animals. However, several clinical trials have found that in aged postmenopausal women who received estrogen replacement therapy, there did not appear to be a reduction in the incidence of stroke. The aim of this study was to investigate the effects of physiological dosages of estrogen on aged female mice subjected to ischemia-reperfusion injury. Adult ovariectomized (OVX) female mice and 22-month-old female mice received daily subcutaneous injections of 100μg/kg or 300μg/kg 17β-estradiol (E2) at the back of the neck for four weeks, and the expression levels of estrogen receptor (ER) α and β in the cerebral cortex were determined using real-time PCR and Western blotting analyses. To mimic ischemic stroke, the mice received middle cerebral artery occlusion (MCAO) treatment for 1h followed by a 24-h reperfusion period. The mice were then subjected to neurological deficit testing and infarct volume evaluation. The aged mice showed higher neurological deficit scores and larger infarct volumes compared with the adult mice. Both the lower and higher physiological dosages of E2 significantly improved the neurological test scores and...
Source: Neuroscience Letters - Category: Neuroscience Source Type: research