Swimming exercise at weaning improves glycemic control and inhibits the onset of monosodium l-glutamate-obesity in mice

Abstract

Swimming exercises by weaning pups inhibited hypothalamic obesity onset and recovered sympathoadrenal axis activity, but this was not observed when exercise training was applied to young adult mice. However, the mechanisms producing this improved metabolism are still not fully understood. Low-intensity swimming training started at an early age and was undertaken to observe glycemic control in hypothalamic-obese mice produced by neonatal treatment with monosodium L-glutamate (MSG). Whereas MSG and control mice swam for 15 min/day, 3 days a week, from the weaning stage up to 90 days old, sedentary MSG and normal mice did not exercise at all. After 14 h of fasting, animals were killed at 90 days of age. Perigonadal fat accumulation was measured to estimate obesity. Fasting blood glucose and insulin concentrations were also measured. Fresh isolated pancreatic islets were used to test glucose-induced insulin release and total catecholamine from the adrenal glands was measured. Mice were also submitted to intraperitoneal glucose tolerance test. MSG-obese mice showed fasting hyperglycemia, hyperinsulinemia, and glucose intolerance. Severe reduction of adrenal catecholamines content has also been reported. Besides, the inhibition of fat tissue accretion, exercise caused normalization of insulin blood levels and glycemic control. The pancreatic islets of obese mice, with impaired glucose-induced insulin secretion, were recovered after swimming exercises. Adrenal catecholamine content was increased by swimming. Results show that attenuation of MSG-hypothalamic obesity onset is caused, at least in part, by modulation of sympathoadrenal axis activity imposed by early exercise, which may be associated with subsequent glucose metabolism improvement.

Effects of taurine supplementation and swimming, associated or not, on obesity and glucose homeostasis in mice

“…The present study corroborates literature data, which shows that the neonatal MSG treatment leads to obesity in Swiss mice, as shown by the increase of Lee index and weight of retroperitoneal fat; in addition to the reduction of NAL of the animals SCOMPARIN et al, 2006;ANDREAZZI et al, 2009). The neonatal MSG treatment causes destruction of the hypothalamic arcuate nucleus, responsible for regulating the release of growth hormone, reducing its secretion that leads to reduced lypolisis and growth of the animal (MAITER et al, 1991).…”

Efeito de um programa de exercício físico moderado em ratos de diferentes modelos de obesidade

“…Esses resultados dão subsídios aos encontrados em nosso estudo, visto que os ratos do grupo NR-S são intolerantes à glicose se comparados aos animais do grupo controle. Outros estudos mostram que animais MSG e DHL também são resistentes à insulina (ROPELLE et al, 2006;LALLI et al, 2008;ANDREAZZI et al, 2009;SCOMPARIN et al, 2009;SHIRAEV et al, 2009). Não obstante, este trabalho mostra que o exercício físico reverteu completamente a resistência à insulina nos três modelos de obesidade, como pode ser observado pelo ivGTT, em que a ASC dos animais NR, MSG e DHL exercitados foi igual à dos animais normais.…”

“…Outros trabalhos comprovaram que a natação de baixa intensidade e de baixo volume realizada três vezes por semana foi capaz de impedir o desenvolvimento da obesidade e resistência à insulina em camundongos tratados com MSG (SCOMPARIN et al, 2006;ANDREAZZI et al, 2009;SCOMPARIN et al, 2009). Nossos resultados mostram que, independentemente do modelo de obesidade, a corrida em esteira três vezes por semana, com a intensidade e o volume propostos em nosso protocolo, foi capaz de causar efeitos similares aos de protocolos de exercícios com frequências de cinco vezes por semana e de intensidades e volumes maiores, como exercícios de endurance encontrados em outros trabalhos (LUCIANO et al, 2002;ROPELLE et al, 2010).…”

Drug-Metabolizing and Antioxidant Enzymes in Monosodium L-Glutamate Obese Mice

“…Development of obesity in this model is explained by lower metabolic rate and lack of physical activity (Martins et al, 2001;Maletinska et al, 2006) rather than excessive energy intake. Lowintensity swimming exercise at early age can improve or attenuate onset of obesity in this model (Scomparin et al, 2006;Andreazzi et al, 2009). …”