Original Contribution Attenuation of doxorubicin-induced contractile and mitochondrial dysfunction in mouse heart by cellular glutathione peroxidase Ye Xiong a,b,1 , Xuwan Liu c,1 , Chuan-Pu Lee b , Balvin H.L. Chua c,d,e, ⁎ ,2 , Ye-Shih Ho a,b, ⁎ ,2 a Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, USA b Department of Biochemistry and Molecular Biology, Wayne State University, Detroit, MI 48201, USA c Department of Pharmacology, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA d Cecile Cox Quillen Laboratory of Geriatric Research, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA e James H. Quillen Veterans Affairs Medical Center, Johnson City, TN 37614, USA Received 5 January 2006; revised 9 February 2006; accepted 16 February 2006 Available online 4 April 2006 Abstract The cardiac toxicity of doxorubicin (DOX), a potent anticancer anthracycline antibiotic, is believed to be mediated through the generation of reactive oxygen species (ROS) in cardiomyocytes. This study aims to determine the function of cellular glutathione peroxidase (Gpx1), which is located in both mitochondria and cytosol, in defense against DOX-induced cardiomyopathy using a line of transgenic mice with cardiac overexpression of Gpx1. The Gpx1-overexpressing hearts were markedly more resistant than nontransgenic hearts to DOX-induced acute functional derangements, including impaired contractility and diastolic properties, decreased coronary flow rate, and reduced heart rate. In addition, DOX treatment impairs mitochondrial function of nontransgenic hearts as evident in a decreased rate of NAD-linked State 3 respiration, presumably a result of inactivation of complex I activity. This is associated with increases in the rates of NAD- and FAD-linked State 4 respiration and declines in P/O ratio, suggesting that the electron transfer and oxidative phosphorylation are uncoupled in these mitochondrial samples. These functional deficits of mitochondria could be largely prevented by Gpx1 overexpression. Taken together, these studies provide new evidence to further support the role of ROS, particularly H 2 O 2 and/or fatty acid hydroperoxides, in causing contractile and mitochondrial dysfunction in mouse hearts acutely exposed to DOX. © 2006 Elsevier Inc. All rights reserved. Keywords: Reactive oxygen species; Doxorubicin; Cellular glutathione peroxidase; Cardiac function; Mitochondrial respiration; Mitochondrial electron-transport chain Introduction Doxorubicin (DOX), a quinone-containing anthracycline anti- biotic, is one of the most effective antimitotics in cancer chemo- therapy. Unfortunately, clinical application of DOX is greatly limited by its acute and chronic cardiotoxicity [1–3]. The acute DOX-induced cardiomyopathy, which includes pericarditis– myocarditis, left ventricular dysfunction, and arrhythmia, was first observed in patients shortly after receiving their first or second course of treatment [4,5]. In the long-term, cardiomyop- athy and congestive heart failure may occur years after treatment cessation. The severity of cardiac damage is generally proportio- nal to the cumulative dose of DOX received by the patients [5–7]. The mechanism of DOX-induced cardiotoxicity is not fully understood. At the cellular level, it is associated with an Free Radical Biology & Medicine 41 (2006) 46 – 55 www.elsevier.com/locate/freeradbiomed Abbreviations: CFR, coronary flow rate; DCIP, 2,6-dichlorophenolindo- phenol; DOX, doxorubicin; Gpx1, cellular glutathione peroxidase; LVDP, left ventricular develop pressure; MnSOD, manganese superoxide dismutase; NOS, nitric oxide synthase; ROS, reactive oxygen species; BSA, bovine serum albumin; EDTA, ethylenediaminetetraacetic acid; EGTA, ethylene glycol-bis(2- aminoethylether)-N, N, N, N-tetraacetic acid; RCI, respiratory control index. ⁎ Corresponding authors. B.H.L. Chua is to be contacted at Cecile Cox Quillen Laboratory of Geriatric Research, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37614, USA. Fax: +1 423 979 3408. Y.-S. Ho, Institute of Environmental Health Sciences, Wayne State University, Detroit, MI 48201, USA. Fax: +1 313 577 0082. E-mail addresses: chua@mail.etsu.edu (B.H.L. Chua), yho@wayne.edu (Y.-S. Ho). 1 These authors contributed equally to this work. 2 These authors share equal senior authorship. 0891-5849/$ - see front matter © 2006 Elsevier Inc. All rights reserved. doi:10.1016/j.freeradbiomed.2006.02.024