Morphofunctional adaptations and molecular responses of the rats skeletal muscle submitted to endurance training

• Grant number: 09/53004-8
• Support Opportunities: Regular Research Grants
• Start date: February 01, 2010
• End date: January 31, 2012
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Maeli Dal Pai
• Grantee: Maeli Dal Pai
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil

Abstract

Recent researches seek elucidate key molecular mechanisms involved in skeletal muscle adaptations to exercise. In this context, the insulin-like growth factor-I (IGF-I), Calcineurina (CaN) and miostatina (MSTN) has been identified as main molecular mediators of muscle adaptations to chronic endurance training. However, the differential expression of these proteins in different muscles during aerobic training remains unknown. The purpose of this study will be evaluate the morphofunctional adaptations and gene expression of IGF-I, CaN and MSTN in glycolytic (plantaris) and oxidative (soleus) muscle of rats submitted to long-term aerobic training. Male Wistar rats (4 months old, 300 to 400 g) will be divided into 2 groups: trained animals (T, n=8) and control animals (C, n=8). The T group will be submitted a program of swimming aerobic training for 8 weeks (5 days/week). The volume and intensity of training will be progressive, being equivalent to 10 min, without overloading (lg. week), 20 min, 1% (2nd wk), 25, 30, 35 and 40 min, 3% (from beginning to the end of 3rd wk), 45, 50, 55 and 60 min, 5% (from beginning to the end of 4th wk) and 60 min, 5% (5th to 8th wk). At the end of training the animals will be sacrificed and the soleus and plantaris muscles dissected and removed. For morphological and morphometrical analysis of muscle fibers will be performed the HE staining and the histochemistry reaction of the myofibrillar adenosine triphosphatase (mATPase). Myosin heavy chain (MHC) isoforms will be analyzed by Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) in duplicate, and gene and protein expression of IGF-I, CaN and MSTN by Real-time PCR after reverse transcription (qRT-PCR) and Western Blot, respectively. The biochemical analyses of lactate dehydrogenase (LDH) and citrate synthase (CS) enzymes from muscle tissue will also be performed. The blood serum will be collected to measure serum levels of IGF-I, by Radioimmunoassay method. The data obtained will be submitted to appropriate statistical analysis. (AU)