Influência do sexo nas adaptações hemodinâmicas, neuroimunes e musculares induzidas pelo treinamento físico resistido dinâmico em modelo experimental de hipertensão arterial

Abstract

Cardiovascular diseases are the main cause of death in the world. Among the risk factors for its development, hypertension has a high prevalence in both genders. Dynamic resistance exercise training has been recommended as a complement to the aerobic exercise training in the hypertension treatment. However, few studies evaluated the effects of resistance exercise training, mainly comparing the influence of gender. In this sense, the aim of this study was to evaluate and compare the effects of dynamic resistance training (moderate intensity) between male and female spontaneously hypertensive rats in muscular, hemodynamic, neuroimmune and oxidative stress parameters. Thirty-four spontaneously hypertensive rats (SHR, 3 months old) were divided into 4 groups (n = 8): sedentary (FS) and trained (FT) females; sedentary (MS) and trained (MT) males. The FT and MT groups were submitted to 8 weeks of resistance exercise training in the ladder (40-60% of the maximal load test). At the end of the exercise training protocol, muscular, hemodynamics, baroreflex sensitivity, cardiovascular autonomic modulation, inflammatory profile and oxidative stress parameters were evaluated. Comparing the genders differences, the MS group showed higher body weight, fat deposition, and lower glycemia in relation to the FS group. Although we did not observe differences in blood pressure (BP), the vascular sympathetic component were higher in the MS group when compared to the FS group. The MS group also presented a lower spontaneous baroreflex sensitivity and plasma nitrites than the FS group. The MS group showed a lower cardiac TNF-alpha/IL-10 ratio and the superoxide anion concentration, as well as a higher hydrogen peroxide concentration and lipoperoxidation in relation to the FS group. Resistance exercise training induced an increase in strength, reduction in plasma triglycerides, an increase on phosphofructokinase activity, type IIb heavy myosin chain expression and hypertrophy in the plantar muscle in both trained groups (MT and FT) in relation to the respective sedentary groups (MS and FS). Although we did not observe reduction of BP after the exercise training protocol, there were an improvement in baroreflex sensitivity in the FT group compared to the FS (bradycardic response: 0.74 ± 0.09 vs. 0.48 ± 0.07 and tachycardic response: 2.18±0.18 vs. 1.59±0.10 bpm/mmHg, respectively), which was not observed in the male groups. The MT group showed a decrease in systolic blood pressure variability (33.84 ± 3.49 mmHg²) and vascular sympathetic component (LF: 6.24 ± 1.60 mmHg²) when compared to the MS group (65.88 ± 4, 26 and 11.79 ± 1.50 mmHg², respectively). Trained groups showed a higher spontaneous baroreflex sensitivity. There was an improvement in the cardiac inflammatory profile, characterized by reduction of IL-6 in males (MT vs. MS) and increase of IL-10 and reduction of TNF-alpha/IL-10 ratio in females (FT vs FS), as well as a reduction of oxidative stress, demonstrated by increased redox balance GSH/GSSG (MT: 11.32±0.47 vs. MS: 8.63±0.32; FT: 9.84±0.49 vs. FS: 7.95±0.38 nmol/g of tissue), reduction of damage markers (lipoperoxidation and protein oxidized) in the trained groups (MT and FT), and increase on superoxide dismutase antioxidant enzyme only in the group FT in relation to the FS group. In conclusion, moderate-intensity dynamic resistance training improves SBR, most notably in trained SHR females, and the AP variability, observed in trained SHR males, regardless of BP reduction, which may be associated with attenuation in inflammation and oxidative stress, inducing reduction in target organ damage and reducing cardiovascular risk in hypertensives.