Hyperbaric oxygenation and 20-hydroxyeicosatetreanoic acid inhibition reduce stroke volume in female diabetic Sprague-Dawley rats

Exp Physiol. 2017 Dec 1;102(12):1596-1606. doi: 10.1113/EP086402. Epub 2017 Nov 2.

Abstract

What is the central question of this study? Is there a beneficial effect and what are the mechanisms of acute and multiple hyperbaric oxygenation (HBO2 ) exposures on the outcome of cerebral tissue injury induced by a transient middle cerebral artery occlusion model in diabetic female rats? Are 20-hydroxyeicosatetreanoic acid and epoxyeicosatrienoic acids involved? What is the main finding and its importance? Equal reduction of cortical and total infarct size in rats treated with HBO2 and HET0016 (20-hydroxyeicosatetreanoic acid production inhibitor) and significant mRNA upregulation of epoxyeicosatrienoic acid-producing enzymes (Cyp2J3 and Cyp2C11) in treated groups suggest that HBO2 and HET0016 are highly effective stroke treatments and that cytochrome P450 metabolites are involved in this therapeutic effect. We evaluated the effects of acute and repetitive hyperbaric oxygenation (HBO2 ), 20-hydroxyeicosatetreanoic acid (20-HETE) inhibition by N-hydroxy-N'-(4-butyl-2methylphenyl)-formamidine (HET0016) and their combination on experimental stroke outcomes. Streptozotocin-induced type 1 diabetic Sprague-Dawley female rats (n = 42; n = 7 per group), were subjected to 30 min of transient middle cerebral artery occlusion (t-MCAO)-reperfusion and divided into the following groups: (1) control group, without treatment; and groups exposed to: (2) HBO2 ; (3) multiple HBO2 (HBO2 immediately and second exposure 12 h after t-MCAO); (4) HET0016 pretreatment (1 mg kg-1 , 3 days before t-MCAO) combined with HBO2 after t-MCAO; (5) HET0016 treatment (1 h before, during and for 6 h after t-MCAO); and (6) HET0016 treatment followed by HBO2 after t-MCAO. Messenger RNA expression of CYP2J3, CYP2C11, CYP4A1, endothelial nitric oxide synthase and epoxide hydrolase 2 was determined by real-time qPCR. Cortical infarct size and total infarct size were equally and significantly reduced in HBO2 - and HET0016-treated rats. Combined treatment with HET0016 and HBO2 provided no significant additive effect compared with HET0016 treatment only. Messenger RNA of Cyp2J3 was significantly increased in all study groups, and mRNA of Cyp2C11 was significantly increased in the multiple HBO2 group and the HET0016 treatment followed by HBO2 group, compared with the control group. Expression of endothelial nitric oxide synthase was significantly increased after HBO2 treatments, and expression of epoxide hydrolase 2 was increased in all groups compared with the control group. In diabetic female Sprague-Dawley rats, HBO2 and HET0016 are highly effective stroke treatments, suggesting the involvement of cytochrome P450 metabolites and the NO pathway in this therapeutic effect.

Keywords: brain ischemia; diabetes mellitus; hyperbaric oxygenation; stroke.

Publication types

  • Comparative Study

MeSH terms

  • Amidines / pharmacology*
  • Animals
  • Aryl Hydrocarbon Hydroxylases / genetics
  • Aryl Hydrocarbon Hydroxylases / metabolism
  • Brain / drug effects*
  • Brain / metabolism
  • Brain / pathology
  • Combined Modality Therapy
  • Cytochrome P-450 Enzyme System / genetics
  • Cytochrome P-450 Enzyme System / metabolism
  • Cytochrome P450 Family 2 / genetics
  • Cytochrome P450 Family 2 / metabolism
  • Cytochrome P450 Family 4 / genetics
  • Cytochrome P450 Family 4 / metabolism
  • Diabetes Mellitus, Experimental / metabolism
  • Diabetes Mellitus, Experimental / physiopathology
  • Diabetes Mellitus, Experimental / therapy*
  • Diabetes Mellitus, Type 1 / metabolism
  • Diabetes Mellitus, Type 1 / physiopathology
  • Diabetes Mellitus, Type 1 / therapy*
  • Epoxide Hydrolases / genetics
  • Epoxide Hydrolases / metabolism
  • Female
  • Gene Expression Regulation, Enzymologic
  • Hydroxyeicosatetraenoic Acids / metabolism*
  • Hyperbaric Oxygenation*
  • Infarction, Middle Cerebral Artery / metabolism
  • Infarction, Middle Cerebral Artery / pathology
  • Infarction, Middle Cerebral Artery / physiopathology
  • Infarction, Middle Cerebral Artery / therapy*
  • Neuroprotective Agents / pharmacology*
  • Nitric Oxide Synthase Type III / genetics
  • Nitric Oxide Synthase Type III / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats, Sprague-Dawley
  • Reperfusion Injury / metabolism
  • Reperfusion Injury / pathology
  • Reperfusion Injury / physiopathology
  • Reperfusion Injury / prevention & control*
  • Steroid 16-alpha-Hydroxylase / genetics
  • Steroid 16-alpha-Hydroxylase / metabolism
  • Time Factors

Substances

  • Amidines
  • Cyp4a1protein, rat
  • HET0016
  • Hydroxyeicosatetraenoic Acids
  • Neuroprotective Agents
  • RNA, Messenger
  • 20-hydroxy-5,8,11,14-eicosatetraenoic acid
  • Cytochrome P-450 Enzyme System
  • Nitric Oxide Synthase Type III
  • Nos3 protein, rat
  • Aryl Hydrocarbon Hydroxylases
  • CYP2C11 protein, rat
  • Cyp2j3 protein, rat
  • Cytochrome P450 Family 2
  • Cytochrome P450 Family 4
  • Steroid 16-alpha-Hydroxylase
  • Epoxide Hydrolases
  • EPHX2 protein, rat