title: Delayed cardioprotection with isoflurane: role of reactive oxygen and nitrogen.
abstract: We determined whether isoflurane can confer delayed cardioprotection in the adult rat by triggering increased production of reactive oxygen (ROS) and nitrogen species (RNS). Our objectives were to determine 1) the concentration of isoflurane that confers delayed cardioprotection in the adult rat, 2) the role of ROS and RNS in the induction of delayed cardioprotection, and 3) the cellular sources of ROS and RNS responsible for induction of delayed cardioprotection by isoflurane. Male Sprague-Dawley rats at 8 wk of age (n = 8 rats/group) were exposed to 0.5%, 0.8%, 1%, and 2% (vol/vol) isoflurane-100% oxygen for 2 h. Isoflurane conferred delayed cardioprotection 24 h later at a concentration of 0.8% (vol/vol). Administration of manganese (III) tetrakis (4-benzoic acid)porphyrin chloride (MnTBAP), a superoxide scavenger (15 mg/kg ip), or N(G)-nitro-L-arginine methyl ester (L-NAME), a general nitric oxide synthase inhibitor (15 mg/kg ip), 15 min before isoflurane treatment abolished the delayed cardioprotective effects of isoflurane. MnTBAP and L-NAME had no effect on delayed cardioprotection in untreated hearts. Perfusion of isolated hearts with hydroethidine, a fluorescent probe for superoxide, after isoflurane treatment resulted in a twofold increase in ethidine staining of isoflurane-treated hearts compared with untreated controls, which was attenuated by myxothiazol, an inhibitor of the mitochondrial electron transport chain (0.2 mg/kg ip) and L-NAME (15 mg/kg ip). Nitrite and nitrate content in isoflurane-treated hearts was 1.5-fold higher than in untreated hearts, whereas myocardial reduced glutathione levels were decreased by 13% in 0.8% but not in 1.0% isoflurane-treated hearts. We conclude that isoflurane confers delayed cardioprotection in the adult rat, triggered by ROS and RNS.
authors.affiliation: Division of Pediatric Surgery, Free Radical Research Center, Medical College of Wisconsin, 8701 Watertown Plank Rd., Milwaukee, WI 53226, USA.
authors.forename: Yang
authors.initials: Y
authors.lastname: Shi
authors.forename: William C
authors.initials: WC
authors.lastname: Hutchins
authors.forename: Jidong
authors.initials: J
authors.lastname: Su
authors.forename: Daniel
authors.initials: D
authors.lastname: Siker
authors.forename: Neil
authors.initials: N
authors.lastname: Hogg
authors.forename: Kirkwood A
authors.initials: KA
authors.lastname: Pritchard
authors.forename: Agnes
authors.initials: A
authors.lastname: Keszler
authors.forename: James S
authors.initials: JS
authors.lastname: Tweddell
authors.forename: John E
authors.initials: JE
authors.lastname: Baker
mesh_terms: D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D019610:Cytoprotection; D005740:Gases / Q000097:blood; D005978:Glutathione / Q000378:metabolism; D006321:Heart / Q000187:drug effects*; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D018685:Anesthetics, Inhalation; D005740:Gases; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D007530:Isoflurane; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D005978:Glutathione