Time-course effects of aerobic exercise training on cardiovascular and renal parameters in 2K1C renovascular hypertensive rats

Abstract

Exercise training (Ex) has been recommended for its beneficial effects in hypertensive states. The present study evaluated the time-course effects of Ex without workload on mean arterial pressure (MAP), reflex bradycardia, cardiac and renal histology, and oxidative stress in two-kidney, one-clip (2K1C) hypertensive rats. Male Fischer rats (10 weeks old; 150–180 g) underwent surgery (2K1C or SHAM) and were subsequently divided into a sedentary (SED) group and Ex group (swimming 1 h/day, 5 days/week for 2, 4, 6, 8, or 10 weeks). Until week 4, Ex decreased MAP, increased reflex bradycardia, prevented concentric hypertrophy, reduced collagen deposition in the myocardium and kidneys, decreased the level of thiobarbituric acid-reactive substances (TBARS) in the left ventricle, and increased the catalase (CAT) activity in the left ventricle and both kidneys. From week 6 to week 10, however, MAP and reflex bradycardia in 2K1C Ex rats became similar to those in 2K1C SED rats. Ex effectively reduced heart rate and prevented collagen deposition in the heart and both kidneys up to week 10, and restored the level of TBARS in the left ventricle and clipped kidney and the CAT activity in both kidneys until week 8. Ex without workload for 10 weeks in 2K1C rats provided distinct beneficial effects. The early effects of Ex on cardiovascular function included reversing MAP and reflex bradycardia. The later effects of Ex included preventing structural alterations in the heart and kidney by decreasing oxidative stress and reducing injuries in these organs during hypertension.

Swimming training induces liver adaptations to oxidative stress and insulin sensitivity in rats submitted to high-fat diet

“…In previous studies we found that rats with renovascular hypertension (2K1C) submitted to swimming training showed reversal of altered cardiovascular parameters, reduced collagen deposition in the myocardium and the kidneys, reduced TBARS concentration in the left ventricle, and increased CAT activity in the left ventricle and kidney [16]. In the present study, PT improved the physical fitness of rats with MS, as shown by the decrease in the blood concentration of lactate and in the HR.…”

“…Different lines of evidence suggest that regular PT induces beneficial adaptations in diseases associated with oxidative stress, including high blood pressure, type II diabetes and Alzheimer's disease [3,16,17]. In previous studies we found that rats with renovascular hypertension (2K1C) submitted to swimming training showed reversal of altered cardiovascular parameters, reduced collagen deposition in the myocardium and the kidneys, reduced TBARS concentration in the left ventricle, and increased CAT activity in the left ventricle and kidney [16].…”

“…CAT activity was measured by the rate of decrease of hydrogen peroxide (H 2 O 2 ) at 240 nm. The total protein content in the samples of organ homogenates was determined using the Bradford method [16,21,22]. The results were expressed as activity per milligram of protein.…”

“…As an index of lipid peroxidation, we used the formation of TBARS during an acid-heating reaction [16,23]. Liver samples (100 mg) were homogenized in KPE (potassium phosphate-EDTA) buffer (pH 7.4) and centrifuged (10 000g, 10 min, at 4°C).…”

Exercise training attenuates angiotensin II‐induced vasoconstriction in the aorta of normotensive but not hypertensive rats

“…However, Maia et al. (2015) suggested that blood pressure reduction occurs up to week 4 of exercise training. According to these authors, from week 6 to week 10, the blood pressure levels in the 2K1C animals submitted to exercise become similar to those observed in the sedentary 2K1C rats.…”