Effects of concurrent training in the muscle sattelite cells of elderly

Author(s)

Miguel Soares Conceição

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Educação Física
• Defense date: 2015-12-18

Examining board members

Claudia Regina Cavaglieri; Patricia Chakur Brum; Valmor Alberto Augusto Tricoli; Bruno Rodrigues; André Fattori

• Advisor: Claudia Regina Cavaglieri

Abstract

Several studies have been shown that aging may induce sarcopenia which is characterized for decreasing muscle cross sectional area (CSA) and capacity of force generation. Moreover, aging may induce a decrease of cardiorespiratory capacity. Thus, to reduce or reverse adverse effects of aging, some studies have suggested perform resistance training (RT) and endurance training (ET) in the same period of time, called concurrent training (CT). However, despite the benefits from CT, this kind of training is also associated with interference effect. The interference effect is characterized to show less hypertrophy and capacity of force generation after CT than RT alone. According that satellite cells (SC) are important to muscle hypertrophy, some studies have showed the SC response after RT. Although important to muscle hypertrophy after RT, there are no studies that investigated SC response after CT, especially in elderly. Thus, to provide some insight to this issue the main of this study was to compare the number of SC and myonuclei and the genic expression of IGF-1 and myostatin involved in SC activation, after 12 weeks of CT and RT in elderly. Twenty four healthy elderly subjects (64±4 years, 64±4 Kg, 1.64±0.11 m) with no experience in ET or TR six months before experimental period were balanced and were randomly allocated in one of the following groups: concurrent training (CT, n=8, 4 male and 4 female), resistance training (RT, n=9, 5 male e 4 females) or control group (GC, n=7, 4 male e 3 female) and after were engaged in 12 weeks of intervention. Before and after 12 weeks, all subjects underwent to one muscle biopsy which number of SC and myonuclei were detected by immunofluorescence and genic expression detected by Deep Sequence, strength test (1-RM), maximal oxygen uptake test (VO2max) and magnetic resonance imaging (MRI). The RT protocol was performed twice a week in the leg press 45° machine (4x10 with 70-80% of 1-RM and 60s of rest). The CT protocol was performed with same RT protocol followed by a 60-85% of VO2max during 40-50 min. The CG did not perform any exercise. After compare data using software SAS 9.0 and a mixed model, it was fond that CT and RT increase muscle hypertrophy and capacity of force generation significantly (P< 0.05) comparing with pre moment, but no differences were found between groups. No significant interaction was found to number of SC or to the number of myonuclei. Also, no significant modifications were found to genic expression of IGF-1, myostatin and MyoD. There was a significant change to PAX7 gene expression after CT. In summary, 12 weeks of CT in elderly weas able to increase muscle strength and hypertrophy similar to RT, however neither CT nor RT showed increase number of SC or myonuclei. Furthermore, there were no modifications to genic expression of IGF-1 or myostatin after CT or RT (AU)

• FAPESP's process: 12/09709-0 - EFFECTS OF CONCURRENT TRAINING IN THE NUMBER OF SATELLITE CELLS IN AGING
• Grantee: Miguel Soares Conceição
• Support Opportunities: Scholarships in Brazil - Doctorate