Glutathione deficiency intensifies ischaemia-reperfusion induced cardiac dysfunction and oxidative stress.
The efficacy of glutathione (GSH) in protecting ischaemia-reperfusion (I-R) induced cardiac dysfunction and myocardial oxidative stress was studied in open-chest, stunned rat heart model. Female Sprague-Dawley rats were randomly divided into three experimental groups: (1) GSH-depletion, by injection of buthionine sulphoxamine (BSO, 4 mmol kg(-1), i.p.) 24 h prior to I-R, (2) BSO injection (4 mmol kg(-1), i.p.) in conjunction with acivicin (AT125, 0.05 mmol kg(-1), i.v.) infusion 1 h prior to I-R, and (3) control (C), receiving saline treatment. Each group was further divided into I-R, with surgical occlusion of the main left coronary artery (LCA) for 30 min followed by 20 min reperfusion, and sham. Myocardial GSH content and GSH : glutathione disulphide (GSSG) ratio were decreased by approximately 50% (P < 0.01) in both BSO and BSO + AT125 vs. C. Ischaemia-reperfusion suppressed GSH in both left and right ventricles of C (P < 0.01) and left ventricles of BSO and BSO + AT125 (P < 0.05). Contractility (+dP/dt and -dP/dt) in C heart decreased 55% (P < 0.01) after I and recovered 90% after I-R, whereas +/-dP/dt in BSO decreased 57% (P < 0.01) with ischaemia and recovered 76 and 84% (P < 0.05), respectively, after I-R. For BSO + AT125, +/-dP/dt were 64 and 76% (P < 0.01) lower after ischaemia, and recovered only 67 and 61% (P < 0.01) after I-R. Left ventricular systolic pressure in C, BSO and BSO + AT125 reached 95 (P > 0.05) 87 and 82% (P < 0.05) of their respective sham values after I-R. Rate-pressure double product was 11% (P > 0.05) and 25% (P < 0.05) lower in BSO and BSO + AT125, compared with Saline, respectively. BSO and BSO + AT125 rats demonstrated significantly lower liver GSH and heart Mn superoxide dismutase activity than C rats after I-R. These data indicate that GSH depletion by inhibition of its synthesis and transport can exacerbate cardiac dysfunction inflicted by in vivo I-R. Part of the aetiology may involve impaired myocardial antioxidant defenses and whole-body GSH homeostasis.
Leichtweis
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Department of Kinesiology and Nutritional Science, University of Wisconsin-Madison, WI, USA.
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D000818:Animals; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D004195:Disease Models, Animal; D004359:Drug Therapy, Combination; D005260:Female; D005978:Glutathione / Q000172:deficiency* / Q000378:metabolism; D006321:Heart / Q000187:drug effects; D007555:Isoxazoles / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008929:Mitochondria, Heart / Q000187:drug effects / Q000378:metabolism; D009200:Myocardial Contraction / Q000187:drug effects; D015428:Myocardial Reperfusion Injury / Q000378:metabolism*; D017682:Myocardial Stunning / Q000139:chemically induced / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D016276:Ventricular Function / Q000187:drug effects
D007555:Isoxazoles; D019328:Buthionine Sulfoximine; D005978:Glutathione; C006303:acivicin