Does Croton Argyrophyllus Extract Has an Effect on Muscle Damage and Lipid Peroxidation in Rats Submitted to High Intensity Strength Exercise?

Many species of the genus Croton have been used for anti-inflammatory, antiproliferative, antidiabetic, and antitumor purposes. The objective was to evaluate the effect of a hydroethanolic extract (HEE) from the inner bark of Croton argyrophyllus (Euphorbiaceae) on muscle damage and oxidative stress in rats after high intensity exercise. The animals were divided into four groups: (i) the sedentary group (SV; n = 7), (ii) the exercise vehicle group (EV, n = 7), (iii) the sedentary group HEE (SHG; n = 7) composed of sedentary animals and treated with the hydroethanolic extract of C. argyrophyllus (200 mg/kg, v.o.), and (iv) the HEE exercise group (HEE; n = 7) composed of animals submitted to resistance exercise (RE) and treated with the hydroethanolic extract of C. argyrophyllus (200 mg/kg, v.o.). In the 2,2-Diphenyl-1-picrylhydrazyl (DPPH) test, the HEE showed lower values of inhibition potential (IP%) at 39.79% compared to gallic acid, 87.61%, and lipoperoxidation inhibition at 27.4% (100 µg/mL) or 28.6% (200 µg/mL) (p < 0.001). There was inhibition in free radicals in vivo. The HEE of C. argyrophyllus partially reduced the biomarkers of oxidative stress in muscle tissue and muscular damage (creatine kinase (CK) and Lactate Dehydrogenase (LDH)) (p < 0.05) in rats, and in this sense it can be an aid to the recovery process after exhaustive efforts.

Fractionated Concurrent Exercise throughout the Day Does Not Promote Acute Blood Pressure Benefits in Hypertensive Middle-aged Women

Hypertension is a chronic disease that affects about 30% of the world’s population, and the physical exercise plays an important role on its non-pharmacological treatment. Anywise, the dose–response of physical exercise fractionation throughout the day demands more investigation, allowing new exercise prescription possibilities. Therefore, this study aimed to analyze the acute blood pressure (BP) kinetics after 1 h of exercises and the BP reactivity after different concurrent exercise (CE) sessions and its fractioning of hypertensive middle-aged women. In this way, 11 hypertensive women voluntarily underwent three experimental sessions and one control day [control session (CS)]. In the morning session (MS) and night session (NS), the exercise was fully realized in the morning and evening, respectively. For the fractionized session (FS), 50% of the volume was applied in the morning and the remaining 50% during the evening. The MS provided the greatest moments (p ≤ 0.05) of post-exercise hypotension (PEH) for systolic BP (SBP) and highest reduction of BP reactivity for SBP (~44%) and diastolic BP (DBP) (~59%) compared to CS (p ≤ 0.05). The findings of the present study have shown that MS is effective for PEH to SBP, as well as it promotes high quality of attenuation for BP reactivity, greater than the other sessions.

Increased Nitric Oxide Bioavailability and Decreased Sympathetic Modulation Are Involved in Vascular Adjustments Induced by Low-Intensity Resistance Training

Resistance training is one of the most common kind of exercise used nowadays. Long-term high-intensity resistance training are associated with deleterious effects on vascular adjustments. On the other hand, is unclear whether low-intensity resistance training (LI-RT) is able to induce systemic changes in vascular tone. Thus, we aimed to evaluate the effects of chronic LI-RT on endothelial nitric oxide (NO) bioavailability of mesenteric artery and cardiovascular autonomic modulation in healthy rats. Wistar animals were divided into two groups: exercised (Ex) and sedentary (SED) rats submitted to the resistance (40% of 1RM) or fictitious training for 8 weeks, respectively. After LI-RT, hemodynamic measurements and cardiovascular autonomic modulation by spectral analysis were evaluated. Vascular reactivity, NO production and protein expression of endothelial and neuronal nitric oxide synthase isoforms (eNOS and nNOS, respectively) were evaluated in mesenteric artery. In addition, cardiac superoxide anion production and ventricle morphological changes were also assessed. In vivo measurements revealed a reduction in mean arterial pressure and heart rate after 8 weeks of LI-RT. In vitro studies showed an increased acetylcholine (ACh)-induced vasorelaxation and greater NOS dependence in Ex than SED rats. Hence, decreased phenylephrine-induced vasoconstriction was found in Ex rats. Accordingly, LI-RT increased the NO bioavailability under basal and ACh stimulation conditions, associated with upregulation of eNOS and nNOS protein expression in mesenteric artery. Regarding autonomic control, LI-RT increased spontaneous baroreflex sensitivity, which was associated to reduction in both, cardiac and vascular sympathetic modulation. No changes in cardiac superoxide anion or left ventricle morphometric parameters after LI-RT were observed. In summary, these results suggest that RT promotes beneficial vascular adjustments favoring augmented endothelial NO bioavailability and reduction of sympathetic vascular modulation, without evidence of cardiac overload.