Cryobiology 52 (2006) 74–82 www.elsevier.com/locate/ycryo 0011-2240/$ - see front matter  2005 Elsevier Inc. All rights reserved. doi:10.1016/j.cryobiol.2005.09.006 Oxidative DNA damage and antioxidant defenses in the European common lizard (Lacerta vivipara) in supercooled and frozen states  Yann Voituron a,¤,1 , Stéphane Servais a,1 , Caroline Romestaing a , Thierry Douki b , Hervé Barré a a Physiologie Intégrative Cellulaire et Moléculaires (UMR 5123), Campus La Doua, Bât 404, 4° Etage, 43 bd du 11 novembre 1918, F-69622 Villeurbanne Cedex, France b Laboratoire “Lesions des Acides Nucleiques”, Service de Chimie Inorganique et Biologique, UMR 5046, CEA/DSM/Département de Recherche Fondamentale sur la Matière Condensée, CEA-Grenoble, 38054 Grenoble Cedex 9, France Received 3 September 2004; accepted 30 September 2005 Available online 29 November 2005 Abstract The European common lizard (Lacerta vivipara) tolerates long periods at sub-zero temperatures, either in the super- cooled or the frozen state. Both physiological conditions limit oxygen availability to tissues, compelling lizards to cope with potential oxidative stress during the transition from ischemic/anoxic conditions to reperfusion with aerated blood during recovery. To determine whether antioxidant defenses are implicated in the survival of lizards when facing sub-zero temper- atures, we monitored the activities of antioxidant enzymes and oxidative stress either during supercooling or during freez- ing exposures (20 h at ¡2.5 °C) and 24 h after thawing in two organs of lizards—muscle and liver. Supercooling induced a signiWcant increase in the total SOD and GPx activity in muscle (by 67 and 157%, respectively), but freezing had almost no eVect on enzyme activity, either in muscle or in liver. By contrast, thawed lizards exhibited higher GPx activity in both organs (a 133% increase in muscle and 59% increase in liver) and a signiWcant decrease in liver catalase activity (a 47% diVerence between control and thawed lizards). These data show that supercooling (but not freezing) triggers activation of the antioxidant system and this may be in anticipation of the overgeneration of oxyradicals when the temperature increases (while thawing or at the end of supercooling). Oxidative stress was assessed from the content of 8-oxodGuo and the diVer- ent DNA adducts resulting from lipid peroxidation, but it was unaltered whatever the physiological state of the lizards, thus demonstrating the eYciency of the antioxidant system that has been developed by this species. Overall, antioxidant defenses appear to be part of the adaptive machinery for reptilian tolerance to sub-zero temperatures.  2005 Elsevier Inc. All rights reserved. Keywords: Freeze tolerance; Supercooling; Reptile; Superoxide dismutase; Catalase; Glutathione peroxidase; Lipid peroxidation induced DNA adducts; 8-oxodGuo  This work was supported by a research grant from the CNRS, France. * Corresponding author. Fax: +33 4 72 43 11 72. E-mail address: yann.voituron@univ-lyon1.fr (Y. Voituron). 1 These authors contributed equally to this work.