Efeitos da associação de treinamento físico aeróbio e resistido em parâmetros autonômicos e de estresse oxidativo em ratas hipertensas ooforectomizadas

Abstract

Hypertension is one of the main risk factors for cardiovascular disease mainly in postmenopausal women. In this context, the sympathetic overactivity, the oxidative stress and the inflammation seem to have play an important role in development of this disease. On the other hand, aerobic exercise training (ET) has been suggested to prevention and/or treatment of several diseases. Moreover, resistance ET has been recommended as a complement of aerobic ET. However, the effects of the association of these types of ET (combined exercise training) in this condition remains unclear. Thus, the aim of this study was to invetigate the effects of combined ET on hemodynamic, cardiovascular autonomic modulation, oxidative stress and inflammation parameters in hypertensive-ovariectomized rats. Female Wistar and SHR rats were divided into (n=8 per group): control (c), hypertensive (H), hypertensive ovariectomized (HO) and hypertensive ovariectomized submitted to combined exercise training (THO). Trained group was submitted to an exercise protocol on a treadmill and vertical ladder (5d/w; 8wk; 40-60% of maximal capacity). Arterial pressure (AP) was directly measured (Windaq, 2 KHz), and cardiovascular autonomic modulation was assessed by spectral analysis. The baroreflex sensitivity was measured by administration of vasoactive drugs. Oxidative stress was evaluated by lipid peroxidation and by antioxidant capacity in cardiac and renal tissues. Inflammatory markers were assessed in cardiac tissue. We observed an increase in mean AP in H group (165±3 mmHg) when compared to C group (113±1.5 mmHg); and an additional increase in AP in HO group (176±4 mmHg) when compared to other groups. However, THO group (155±3 mmHg) showed a reduction in AP associated with resting bradycardia. We observed a normalization in THO group in the pulse interval of variance (VAR-IP) and in baroreceptor induced-bradycardic responses. The HO group (50.78±4.61 mmHg2) presented an additional impairment in systolic AP variability when compared to C and H groups (23.69±0.45 and 34.09±2.37 mmHg2 respectively). However, the trained group was able to mitigate this dysfunction (THO: 30.09±2.03 mmHg2). Additionally, it was observed an attenuation on vascular sympathetic modulation in THO group (5.72±0.60 mmHg2) compared to HO group (7.69±0.46 mmHg2). Ovariectomy induced an additional increase on oxidative stress assessed by TBARS in relation to others groups in cardiac and renal tissues. However, the THO group showed reduction in this parameter in cardiac (THO: 3.84±0.43 vs. HO: 9.18±0.81 µmol/mg protein) and renal tissues (THO: 2.68±0.21 vs. HO: 4.58±0.40 µmol/mg protein). The THO group presented an increase in total non-enzymatic antioxidant capacity (TRAP) when compared to others groups. There was a reduction of IL-10 in ovariectomized groups (HO and THO vs. C). Furthermore, there was an increase in TNF-α in sedentary hypertensive groups (H and HO vs. C), which has not been observed in THO group. In conclusion, combined exercise training was able to reduce AP associated with BrS improvement, reduction in sympathetic vascular modulation, in oxidative stress and in inflammation in hypertensive ovariectomized rats. These data suggests a positive role of combined exercise training in the management of cardiovascular risk factors in the presence of hypertension and ovarian hormones deprivation.