Accepted Article This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/jpi.12157 This article is protected by copyright. All rights reserved. Received Date : 02-May-2014 Revised Date : 25-Jun-2014 Accepted Date : 27-Jun-2014 Article type : Original Manuscript Melatonin prevents mitochondrial dysfunction and insulin resistance in rat skeletal muscle Bruno G. Teodoro 1,2 , Flavia G. Baraldi 1 , Igor H. Sampaio 1 , Lucas H. M. Bomfim 7 , André L.Queiroz 1 , Madla A. Passos 1 , Everardo M. Carneiro 8 , Luciane C. Alberici 6 , Ramon Gomis ,3,4,5 , Fernanda G. Amaral 9 , José Cipolla-Neto 9 , Michel B Araújo 1 , Tanes Lima 1 , Sérgio Akira Uyemura 6 , *Leonardo R. Silveira 1,6,7 *Elaine Vieira 3 1 Department of Biochemistry and Immunology, Faculty of Medicine of Ribeirão Preto, University of Sao Paulo (USP), Ribeirão Preto, SP, Brazil. 2 Federal Institute of Science Education and Technology of São Paulo, Sao Paulo, Brazil. 3 CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Spain. 4 Diabetes and Obesity Laboratory, IDIBAPS, Barcelona, Spain 5 Hospital Clinic. Universitat de Barcelona, Spain 6 Núcleo Pesquisas em Produtos Naturais e Sintéticos (NPPNS), Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil. 7 School of Physical Education and Sport of Ribeirão Preto; University of Sao Paulo, Ribeirão Preto, SP, Brazil. 8 Departamento de Anatomia Biologia Celular, Fisiologia e Biofísica, Instituto de Biologia, Universidade Estadual de Campinas, Sao Paulo, Brazil 9 Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo Correspondence should be addressed to: Elaine Vieira. Diabetes and Obesity Research Laboratory, CIBERDEM, C/Rossello, 149- 153, 5th floor, Barcelona, Spain. Phone: (+34) 932275400. FAX: (+34) 933129409. Email: evieira@ciberdem.org Leonardo R. Silveira. Department of Biochemistry and Immunology, Faculty of Medicine, University of São Paulo, Ribeirão Preto, Brazil, Telephone/Fax: +55 16 3602-3213; Leonardo R Silveira. E-mail: lrs@icb.usp.br *These authors contributed equally to the present paper. Key words: insulin resistance, melatonin, skeletal muscle, mitochondrial function, diabetes.