Elsevier

Mitochondrion

Volume 20, January 2015, Pages 22-33
Mitochondrion

Physical exercise prior and during treatment reduces sub-chronic doxorubicin-induced mitochondrial toxicity and oxidative stress

https://doi.org/10.1016/j.mito.2014.10.008Get rights and content

Highlights

  • Sub-chronic DOX treatment is accompanied by impairments on heart mitochondrial morphology, bioenergetics and redox signaling

  • Chronic exercise (treadmill or free-wheel) affords beneficial adaptations to heart mitochondrial structure and function

  • Physical exercise prior and during sub-chronic Doxorubicin treatment counteracts heart mitochondrial impairments

Abstract

Doxorubicin (DOX) is an anti-cancer agent whose clinical usage results in a cumulative and dose-dependent cardiotoxicity. We have previously shown that exercise performed prior to DOX treatment reduces the resulting cardiac(mito) toxicity. We sought to determine the effects on cardiac mitochondrial toxicity of two distinct chronic exercise models (endurance treadmill training—TM and voluntary free-wheel activity—FW) when used prior and during DOX treatment.

Male-young Sprague–Dawley rats were divided into six groups (n = 6 per group): SAL + SED (saline sedentary), SAL + TM (12-weeks TM), SAL + FW (12-weeks FW), DOX + SED (7-weeks of chronic DOX treatment 2 mg/kg per week), DOX + TM and DOX + FW. DOX administration started 5 weeks after the beginning of the exercise protocol. Heart mitochondrial ultrastructural alterations, mitochondrial function (oxygen consumption and membrane potential), semi-quantification of oxidative phosphorylation (OXPHOS) proteins and their in-gel activity, as well as proteins involved in mitochondrial oxidative stress (SIRT3, p66shc and UCP2), biogenesis (PGC1α and TFAM), acetylation and markers for oxidative damage (carbonyl groups, MDA,single bondSH, aconitase, Mn-SOD activity) were evaluated. DOX treatment resulted in ultrastructural and functional alterations and decreased OXPHOS. Moreover, DOX decreased complex I activity and content, mitochondrial biogenesis (TFAM), increased acetylation and oxidative stress. TM and FW prevented DOX-induced alteration in OXPHOS, the increase in oxidative stress, the decrease in complex V activity and in complex I activity and content. DOX-induced decreases in TFAM and SIRT3 content were prevented by TM only.

Both chronic models of physical exercise performed before and during the course of sub-chronic DOX treatment translated into an improved mitochondrial bioenergetic fitness, which may result in part from the prevention of mitochondrial oxidative stress and damage.

Introduction

Doxorubicin (DOX, or adriamycin) is an effective antibiotic used to treat several malignancies. Unfortunately, its clinical use is limited by the development of a dose-dependent cardiac toxicity that results in life-threatening cardiomyopathy. DOX-induced cardiomyocyte dysfunction is associated with increased levels of oxidative damage with the involvement of mitochondrial bioenergetic collapse in the process (Wallace, 2007). In fact, sub-chronic DOX-treated rats show defects on heart mitochondrial function, accompanied by compromised mitochondrial electron transport chain activity and increased oxidative stress and damage (Abd El-Gawad and El-Sawalhi, 2004, Berthiaume et al., 2005, Santos et al., 2002).

Among the strategies proposed as effective in counteracting the cardiac side effects associated with DOX treatment, physical exercise has been recommended as a non-pharmacological tool against myocardial injury (Ascensao et al., 2006c, Ascensao et al., 2007, Ascensao et al., 2011b, Powers et al., 2008). Previous work suggested that the advantage of both acute (Ascensao et al., 2011a, Wonders et al., 2008) and chronic exercise models (Ascensao et al., 2005a, Ascensao et al., 2005b, Ascensao et al., 2006a, Chicco et al., 2005, Chicco et al., 2006, Dolinsky et al., 2013) on triggering a preconditioning-like effect on DOX-treated rats with acute single doses includes the protection of cardiac tissue and especially mitochondria against negative remodeling. Recent studies investigated the effects of exercise performed during and following late-onset DOX-induced cardiotoxicity which showed improvements in hemodynamic parameters (Hayward et al., 2012, Hydock et al., 2012a). However, the cellular and molecular mechanisms underlying this protective phenotype induced by exercise against sub-chronic DOX administration, particularly those targeting mitochondria, are unknown. Specifically, whether perturbations in heart mitochondrial oxidative phosphorylation capacity and oxidative modifications associated with sub-chronic cumulative DOX administration are mitigated by “forced” or “voluntary” long-term exercise models performed prior and during the course of treatments have not been determined and represents the novelty of the present study. As patients undergoing chemotherapy experience severe fatigue and display severe exercise intolerance, the intensity and duration of tolerable exercise are likely to be severely limited (Emter and Bowles, 2008). Facing this, we aimed at analyzing the effects of two types of long-term exercise with distinct characteristics regarding volume and intensity on cardiac mitochondrial bioenergetics and oxidative stress markers in rats sub-chronically treated with DOX.

Section snippets

Animals

All experimental procedures were conducted in accordance with the Directive 2010/63/EU of the European Parliament and were approved by the Ethics Committee of the Research Centre in Physical Activity, Heath and Leisure (Faculty of Sport, University of Porto). Thirty-six male 6-weeks old Sprague–Dawley rats were housed in individual cages in 12 h light/dark cycles with free access to food and water.

Animals were randomly divided into six groups (n = 6 per group): saline sedentary (SAL + SED), saline

Results

Heart weight, mitochondrial protein isolation yield as well as the activity of soleus citrate synthase and cTnI are shown in Table 1. As expected, heart weight decreased with DOX treatment (SAL + SED vs. DOX + SED) and TM and FWinduced heart hypertrophy (SAL + TM and SAL + FW vs. SAL + SED and DOX + TM and DOX + FW vs. DOX + SED). TM increased soleus citrate synthase activity in both SAL and DOX-treated animals (SAL + SED vs. SAL + TM and DOX + SED vs. DOX + TM).

Body mass alterations and distances covered by the

Discussion

The main finding of the present study was that TM and FW, performed before and during the course of sub-chronic DOX treatment, prevented mitochondrial dysfunction and regulated oxidative stress. Our objective was to find out whether any of these exercise models was effective in counteracting cardiac mitochondrial structural alterations, compromised mitochondrial biogenesis, oxidative damage and bioenergetic disruption caused by cumulative sub-chronic DOX treatment. The present study

Acknowledgments

This work was supported by the Portuguese Foundation for Science and Technology (FTC) grants as follows: SFRH/BDP/4225/2007, PTDC/DTP-DES/1071/2012-FCOMP-01-0124-FEDER-028618 and PP_IJUP2011_253 to AA, SFRH/BPD/66935/2009 to JM, SFRH/BD/61889/2009 to IMA, SFRH/BD/89807/2012 to SR, PTDC/SAU-TOX/110952/2009, PTDC/SAU-TOX/117912/2010 and PTDC/DTP-FTO/1180/2012 to PJO, Pest-C/SAU/LA0001/2013-2014 to CNC and PEst-OE/SAU/UI0617/2011 to CIAFEL. DRR is supported by Muscletech Network (MTN20100101) and

References (58)

  • J.O. Holloszy et al.

    Mitochondrial citric acid cycle and related enzymes: adaptive response to exercise

    Biochem. Biophys. Res. Commun.

    (1970)
  • L.W. Jones et al.

    Diet, exercise, and complementary therapies after primary treatment for cancer

    Lancet Oncol.

    (2006)
  • A. Lucia et al.

    Cancer-related fatigue: can exercise physiology assist oncologists?

    Lancet Oncol.

    (2003)
  • I. Marques-Aleixo et al.

    In vitro salicylate does not further impair aging-induced brain mitochondrial dysfunction

    Toxicology

    (2012)
  • A.C. Nulton-Persson et al.

    Modulation of mitochondrial function by hydrogen peroxide

    J. Biol. Chem.

    (2001)
  • P.J. Oliveira et al.

    Depletion of adenine nucleotide translocator protein in heart mitochondria from doxorubicin-treated rats—relevance for mitochondrial dysfunction

    Toxicology

    (2006)
  • S.K. Powers et al.

    Exercise-induced cardioprotection against myocardial ischemia–reperfusion injury

    Free Radic. Biol. Med.

    (2008)
  • D.L. Santos et al.

    Carvedilol protects against doxorubicin-induced mitochondrial cardiomyopathy

    Toxicol. Appl. Pharmacol.

    (2002)
  • H. Schagger et al.

    Blue native electrophoresis for isolation of membrane protein complexes in enzymatically active form

    Anal. Biochem.

    (1991)
  • S. Zhou et al.

    Doxorubicin-induced persistent oxidative stress to cardiac myocytes

    Toxicol. Lett.

    (2001)
  • H.M. Abd El-Gawad et al.

    Nitric oxide and oxidative stress in brain and heart of normal rats treated with doxorubicin: role of aminoguanidine

    J. Biochem. Mol. Toxicol.

    (2004)
  • A. Ascensao et al.

    Moderate endurance training prevents doxorubicin-induced in vivo mitochondriopathy and reduces the development of cardiac apoptosis

    Am. J. Physiol. Heart Circ. Physiol.

    (2005)
  • A. Ascensao et al.

    Effects of endurance training and acute doxorubicin treatment on rat heart mitochondrial alterations induced by in vitro anoxia-reoxygenation

    Cardiovasc. Toxicol.

    (2006)
  • A. Ascensao et al.

    Endurance exercise training attenuates morphological signs of cardiac muscle damage induced by doxorubicin in male mice

    Basic Appl. Myol.

    (2006)
  • A. Ascensao et al.

    Acute exercise protects against calcium-induced cardiac mitochondrial permeability transition pore opening in doxorubicin-treated rats

    Clin. Sci. (Lond.)

    (2011)
  • A. Ascensao et al.

    Mitochondria as a target for exercise-induced cardioprotection

    Curr. Drug Targets

    (2011)
  • A.E. Ashour et al.

    Metformin rescues the myocardium from doxorubicin-induced energy starvation and mitochondrial damage in rats

    Oxidative Med. Cell. Longev.

    (2012)
  • J.M. Berthiaume et al.

    Adriamycin-induced oxidative mitochondrial cardiotoxicity

    Cell Biol. Toxicol.

    (2007)
  • J.M. Berthiaume et al.

    Dietary vitamin E decreases doxorubicin-induced oxidative stress without preventing mitochondrial dysfunction

    Cardiovasc. Toxicol.

    (2005)
  • Cited by (0)

    View full text