Protective effects of estrogen combined with sevoflurane in an experimental model of cerebral infarction and focal cerebral ischemia-reperfusion injury

J.-J. Liu, S.-Y. Pan

Department of Neurology, Nanfang Hospital, Southern Medical University, Guangzhou City, Guangdong Province, People’s Republic of China. pansuyue82@yahoo.com.cn

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• Neurology

OBJECTIVE: Potential additive effects of estrogens and sevoflurane against cerebral infarction after transient or permanent middle cerebral artery occlusion (MCAO) have not been addressed. We evaluated these using a rat model of MCAO.

MATERIALS AND METHODS: 60 adult female Sprague-Dawley rats were used in the experiments after ovariectomy. Animals were divided into placebo/no MCAO, placebo + MCAO, and estrogen + MCAO groups. Each group was further subdivided into subgroups exposed to sevoflurane or oxygen. Animals in the placebo group received intraperitoneal injections of saline, whereas the estrogen group animals received intraperitoneal injections of estradiol (1 mg per day). MCAO was performed 1 week after the ovariectomy. Sevoflurane and oxygen subgroups breathed either sevoflurane or oxygen for 30 min during the surgery. Outcomes were the levels of serum estradiol (E2), interleukin (IL)-6, and beta-amyloid protein (β-AP) (all by ELISA), neurological deficit scores (24 hours, 7 and 28 days after the operation), spatial learning and memory (both by the Morris water maze test on days 7 and 28).

RESULTS: MCAO significantly up-regulated serum levels of IL-6 and β-AP (p < 0.05 for both comparisons). The animals that received the combined treatment with estrogen and sevoflurane showed less extensive up-regulation of these markers (p < 0.05 vs. placebo-treated animals). Furthermore, MCAO induced severe neurological dysfunction and disorders of spatial learning and memory. All these were attenuated by the combined treatment.

CONCLUSIONS: We demonstrate neuroprotective effects of pre-conditioning with estrogen and post-conditioning sevoflurane in experimental animal undergoing MCAO.

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