IMR Press / FBL / Volume 13 / Issue 8 / DOI: 10.2741/2889

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Open Access Article
Soluble epoxide hydrolase: regulation by estrogen and role in the inflammatory response to cerebral ischemia
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1 Department of Anesthesiology and Peri-Operative Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239

*Author to whom correspondence should be addressed.

Academic Editor: John Zhang

Front. Biosci. (Landmark Ed) 2008, 13(8), 2833–2841; https://doi.org/10.2741/2889
Published: 1 January 2008
(This article belongs to the Special Issue New frontiers in neurosurgery research)
Abstract

The protection from ischemic brain injury enjoyed by females is linked to the female sex hormone 17beta-estradiol. We tested the hypothesis that neuroprotection by estradiol entails the prevention of ischemia-induced inflammatory response, through suppression of the P450 eicosanoids-metabolizing enzyme soluble epoxide hydrolase (sEH). Ovariectomized female rats with and without estradiol replacement underwent 2-hour middle cerebral artery occlusion (MCAO). SEH expression was determined using Western blot, and inflammatory cytokine mRNA levels were measured at 6, 24 and 48 hours after MCAO. Cytokine mRNA was also measured in sEH-knockout mice, and in rats treated with sEH inhibitors. Estradiol reduced basal and post-ischemic sEH expression. MCAO strongly induced mRNA levels of tumor necrosis factor-alpha, interleukin 6, and interleukin 1beta, which was attenuated in sEH-knockouts, but not by sEH inhibitors. Estradiol replacement exhibited a bimodal effect on cytokine mRNA, with increased early and reduced delayed expression. While estradiol suppresses cerebral sEH expression, and sEH suppression diminishes inflammation after MCAO, our findings suggest that the effect of estrogen on inflammation is complex, and only partially explained by sEH suppression.

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