Exercise intensity, inflammatory signaling and insulin resistance in obese rats.

• Grant number: 10/07503-0
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: August 01, 2010
• End date: March 31, 2011
• Field of knowledge: Health Sciences - Physical Education
• Principal Investigator: Adelino Sanchez Ramos da Silva
• Grantee: Adelino Sanchez Ramos da Silva
• Host Institution: Escola de Educação Física e Esporte de Ribeirão Preto (EEFERP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Purpose: To evaluate the effects of intensity of exercise on insulin resistance and the expression of inflammatory proteins in the skeletal muscle of diet-induced obese rats (DIO) after a single bout of exercise. Methods: In the first exercise protocol, the rats swam for two 3 h bouts, separated by a 45-min rest period (with 6 hours duration - DIO+EXE); and in the second protocol the rats were exercised with 45 min of swimming at 70% of the maximal lactate steady state - MLSS (DIO+MLSS). Results: Our data demonstrated that both protocols of exercise increased insulin sensitivity and increased insulin-stimulated tyrosine phosphorylation of insulin receptor (IR) and insulin receptor substrate-1 (IRS-1) and serine phosphorylation of protein kinase B (Akt) in the muscle of DIO rats by the same magnitude. In parallel, both exercise protocols also reduced protein tyrosine phosphatase 1B (PTP1B) activity and IRS-1 serine phosphorylation, with concomitant reduction in c-jun N-terminal kinase (JNK) and IºB kinase (IKK) activities in the muscle of DIO rats in a similar fashion. Conclusion: Thus, our data demonstrate that exercise protocols with low intensity and high volume or exercise with moderate intensity and low volume represents different strategies to restore insulin sensitivity with the same efficacy. (AU)