Moderate-intensity exercise allows enhanced protection against oxidative stress-induced cardiac dysfunction in spontaneously hypertensive rats

Abstract

The progression of myocardial injury secondary to hypertension is a complex process related to a series of physiological and molecular factors including oxidative stress. This study aimed to investigate whether moderate-intensity exercise (MIE) could improve cardiac function and oxidative stress in spontaneously hypertensive rats (SHRs). Eight-week-old male SHRs and age-matched male Wistar-Kyoto rats were randomly assigned to exercise training (treadmill running at a speed of 20 m/min for 1 h continuously) or kept sedentary for 16 weeks. Cardiac function was monitored by polygraph; cardiac mitochondrial structure was observed by scanning electron microscope; tissue free radical production was measured using dihydroethidium staining. Expression levels of SIRT3 and SOD2 protein were measured by western blot, and cardiac antioxidants were assessed by assay kits. MIE improved the cardiac function of SHRs by decreasing left ventricular systolic pressure (LVSP), and first derivation of LVP (+LVdP/dt max and −LVdP/dt max ). In addition, exercise-induced beneficial effects in SHRs were mediated by decreasing damage to myocardial mitochondrial morphology, decreasing production of reactive oxygen species, increasing glutathione level, decreasing oxidized glutathione level, increasing expression of SIRT3/SOD2, and increasing activity of superoxide dismutase. Exercise training in SHRs improved cardiac function by inhibiting hypertension-induced myocardial mitochondrial damage and attenuating oxidative stresses, offering new insights into prevention and treatment of hypertension.

An energy restriction‐based weight loss intervention is able to reverse the effects of obesity on the expression of liver tumor‐promoting genes

“…The animals from the EX and EREX groups were then familiarized with running on a rodent treadmill (Treadmill system 303401‐R‐04/C, TSE‐Systems, Inc, Chesterfield, MO, USA) for 10 minutes each day, with the initial speed of 10 m/min being increased to 20 m/min over the course of a week (with 0° incline). After that period, the animals ran on the treadmill at a speed of 20 m/min (with 0° incline) for 30 minutes each day for 4 weeks, considered a moderate exercise . To encourage the rats to stay on the treadmill, a slight electrical stimulus was applied from behind (minor intensity up to 3 mA).…”

“…After that period, the animals ran on the treadmill at a speed of 20 m/min (with 0° incline) for 30 minutes each day for 4 weeks, considered a moderate exercise. 25 To encourage the rats to stay on the treadmill, a slight electrical stimulus was applied from behind (minor intensity up to 3 mA).…”

Potential Protective Effects of the Water‐Soluble Chinese Propolis on Hypertension Induced by High‐Salt Intake

“…Several studies have demonstrated that oxidative stress plays a vital role in the development of various vascular diseases. 19 It is believed that maintaining vascular homeostasis is beneficial for the regulation of blood pressure. 20 However, oxidative stress injury reduces the synthesis of eNOS and decreases the bioavailability of NO in vessel walls, which leads to vascular dysfunction and the destruction of vascular homeostasis.…”

Cardiac Effects of Treadmill Running With Different Intensities in a Rat Model

“…However, less is known regarding cardiac adaptations to the different intensities of treadmill running in rats. Most studies have shown that low-and moderate-intensity exercise attenuates abnormal cardiac remodeling and myocardial dysfunction and improves functional capacity [5,12]. Additionally, clinical studies also support this recommendation by identifying the bene ts that can be derived from low-and moderate-intensity exercise [13].…”

“…Improved cardiac performance, along with cardiac hypertrophy, is one major feature of endurance exercise, leading to a constellation of adaptations that affect the structure, electrical conduction, and function of the heart and that contribute to appropriate increases in cardiac output [1,2]. Studies in animal models of exerciseinduced cardiac hypertrophy-here in response to treadmill exercise, voluntary wheel running, and swim training-have shown a preserved or enhanced contractile function and relative cardiac hypertrophy [3][4][5].…”