Nonfunctional overreaching in animal model: inflammatory and hypertrophic adaptations in cardiac muscle

Author(s)

Alisson Luiz da Rocha

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina de Ribeirão Preto (PCARP/BC)
• Defense date: 2017-04-27

Examining board members

Adelino Sanchez Ramos da Silva

• Advisor: Adelino Sanchez Ramos da Silva

Abstract

Nonfunctional overreaching (NFOR) induced by eccentric exercise (EE) in animal model is associated with performance decrement, DNA damage (muscle and serum samples), oxidative stress (muscle and serum samples), low grade chronic inflammation (muscle and serum samples) and insulin signaling impairment (muscle and serum samples). However, the adaptations of cardiac muscle in response to NFOR induced or not induced by EE are unknown. In addition, the mammalian target of rapamycin (mTOR) has a protector effect in the cardiac muscle, suppressing the increase of the proinflammatory cytokines that is related to cardiac dysfunctions. Thus, the main aim of present study was to compare the effects of NFOR based on EE (downhill running) with other two protocols with similar intensity and volume, but performed in uphill and without inclination, on the protein contents related to hypertrophic and inflammatory signaling, on the content of interstitial fibrotic tissue and on genes expression in mice cardiac muscle. The animals were divided on six groups: Naïve (N; sedentary mice), Control (C; sedentary mice submitted to physical tests), Trained (TR; mice submitted to training protocol), Overtraining in downhill (OTR/down; mice submitted to the overtraining protocol in downhill), Overtraining without inclination (OTR; mice submitted to the overtraining protocol without inclination), and Overtraining in uphill (OTR/up; mice submitted to the overtraining protocol in uphill). Regarding metabolic parameters, OTR/down group presented reduced body weight variation at week 8. All OT groups presented performance drop at end of week 8, increased connective tissue content in left ventricle and reduced AMPKalpha activation. OTR/down group presented reduced mTOR and S6RP protein content, and increased betaMHC gene expression. The conclusion is that OT protocols provoked signs of pathological hypertrophy in left ventricle, being this effect more pronounced in OTR/down group. (AU)

• FAPESP's process: 14/25459-9 - Nonfunctional overreaching in animal model: inflammatory and hypertrophic adaptions of the cardiac muscle
• Grantee: Alisson Luiz da Rocha
• Support Opportunities: Scholarships in Brazil - Master