Effects of a Single Bout of Resistance Exercise in Different Volumes on Endothelium Adaptations in Healthy Animals

Abstract

BackgroundResistance exercise (RE) has been recommended for patients with cardiovascular diseases. Recently, a few studies have demonstrated that the intensity of a single bout of RE has an effect on endothelial adaptations to exercise. However, there is no data about the effects of different volumes of RE on endothelium function.ObjectiveThe aim of the study was to evaluate the effects of different volumes of RE in a single bout on endothelium-dependent vasodilatation and nitric oxide (NO) synthesis in the mesenteric artery of healthy animals.MethodsMale Wistar rats were divided into three groups: Control (Ct); low-volume RE (LV, 5 sets x 10 repetitions) and high-volume RE (HV, 15 sets x 10 repetitions). The established intensity was 70% of the maximal repetition test. After the exercise protocol, rings of mesenteric artery were used for assessment of vascular reactivity, and other mesenteric arteries were prepared for detection of measure NO production by DAF-FM fluorescence. Insulin responsiveness on NO synthesis was evaluated by stimulating the vascular rings with insulin (10 nM).ResultsThe maximal relaxation response to insulin increased in the HV group only as compared with the Ct group. Moreover, the inhibition of nitric oxide synthesis (L-NAME) completely abolished the insulin-induced vasorelaxation in exercised rats. NO production showed a volume-dependent increase in the endothelial and smooth muscle layer. In endothelial layer, only Ct and LV groups showed a significant increase in NO synthesis when compared to their respective group under basal condition. On the other hand, in smooth muscle layer, NO fluorescence increased in all groups when compared to their respective group under basal condition.ConclusionsOur results suggest that a single bout of RE promotes vascular endothelium changes in a volume-dependent manner. The 15 sets x 10 repetitions exercise plan induced the greatest levels of NO synthesis.

Treino de Força Reduz Stress Oxidativo Cardíaco e Renal em Ratos com Hipertensão Renovascular

“…O treino de força foi realizado conforme descrito por Tamaki, Uchiyama e Nakano, 19 e conforme já usado em outros estudo. [20][21][22] Resumidamente, esse modelo de treino de força é realizado em um aparelho que simula o agachamento onde o torso do rato é equipado com uma jaqueta de lona, que o mantém na posição ereta (Figura 1). A jaqueta de lona é presa a um suporte de alumínio, apoiado no braço de madeira que segura os pesos levantados pelo animal, e um estimulador elétrico foi conectado ao rabo do rato, de forma que ele recebesse um estímulo elétrico (10-15v, 0,3 s duração, 3 s intervalo).…”

“…A jaqueta de lona é presa a um suporte de alumínio, apoiado no braço de madeira que segura os pesos levantados pelo animal, e um estimulador elétrico foi conectado ao rabo do rato, de forma que ele recebesse um estímulo elétrico (10-15v, 0,3 s duração, 3 s intervalo). 12,[20][21][22] O período de treino durou 12 semanas e foi iniciado 48 horas após o teste 1RM. Cada sessão de treino de força foi realizada com 70% de sobrecarga de 1RM, com quatro sets de 12 repetições e intervalos de noventa segundos.…”

Impact of Lifestyles (Diet and Exercise) on Vascular Health: Oxidative Stress and Endothelial Function

“…In healthy rats, a single resisted exercise session can improve endothelial function and NO synthesis in both the endothelium and the smooth muscle layer of mesenteric and promote insulin-induced vasodilation [ 263 ]. It is proposed that exercise stimulates factors that increase endothelial NO production including vascular distension, catecholamine release, and intermittent hypoxia.…”

“…Exercise training in pigs [ 264 ] and hypertensive rats [ 265 ] has been shown to increase both gene and protein expression of eNOS. It is also suggested that the stimulation of NO production is dependent on the volume of exercise, and a greater demand of oxygen and nutrients is involved in the beneficial effects of exercise on the endothelium [ 263 , 266 ]. Moreover, similar results are observed in hypertensive rats that single session of resisted exercise activates eNOS and promotes vasorelaxation [ 267 ].…”

Endothelial Function and Physical Exercise

“…Mota et al 14 observed that a single resisted exercise session improves the endothelial function, and increases nitric oxide synthesis in both the endothelium and the smooth muscle layer of healthy rats. As a parameter of vascular reactivity, endothelium-dependent vasodilation in the mesenteric artery was evaluated.…”