ABC | Volume 112, Nº5, May 2019

Original Article Effting et al RE Effects: heart and obesity Arq Bras Cardiol. 2019; 112(5):545-552 Table 2 – Insulin tolerance test (ITT) – blood glucose curve Time of collection (Glucose mg/dL and variation in relation to time 0 min) 0 min 5 min 10 min 15 min 20 min 25 min 30 min Pre-exercise SD 154.3 139.2 (-15.0) 98.7 (-55.5) 77.5 (-76.8) 65.2 (-89.0) 56.7 (-97.5) 43.2 (-111.0) SD + RE 129.3 134.7 (+5.5) 57.7 (-71.5) 54.7 (-74.5) 46.7 (-82.5) 35.3 (-94.0) 25.5 (-103.8) DIO 191.0 † 186.0 (-5.0) 125.5 (-65.5) 118.0 (-73.0) 106.5 (-84.5) † 101.3 (-89.8) † 99.0 (-92.0) † DIO + RE 163.8* † 164.5 (+0.8) 128.0 (-35.8) † 115.2 (-48.5) † 107.3 (-56.5) † 100.8 (-63.0) † 99.5 (-64.3) † Post-exercise SD 129.0 97.5 (-31.5) 71.0 (-58.0) 54.5 (-74.5) 59.0 (-70.0) 37.5 (-91.5) 27.0 (-102.0) SD + RE 122.3 102.0 (-20.3) 66.2 (-56.0) 53.5 (-68.8) 42.0 (-80.3)* 23.0 (-99.3) 15.8 (-106.5) DIO 150.8 †‡ 120.7 (-30.0) ‡ 110.5 (-40.3) † 105.5 (-45.3) † 97.0 (-53.8) † 94.0 (-56.8) † 92.0 (-58.8) † DIO + RE 127.8* ‡ 133.5 (+5.8) 93.7 (-34.0) 68.0 (-59.8) ‡ 64.3 (-63.5)* ‡ 58.5 (-69.3)* †‡ 46.5 (-81.3)* †‡ Source: study data. Pre-adaptation/exercise (week 17) and post-exercise (week 26). Blood glucose was measured after 6 hours of fasting (data from the table) at times 0 min (baseline), followed by an intraperitoneal insulin injection (2 U/kg) and measurements at times 5-30 min. *p < 0.05 versus respective untrained; † p < 0.05 versus respective standard diet; ‡ p < 0.05 versus respective pre-exercise. SD: standard diet; RE: resistance exercise; DIO: diet-induced obesity. color from the reaction between the DTNB and thiols compared to the standard curve for GSH was kinetically established at 412 nm for 10 min. Values were expressed as nmol/min/mg protein. Lipoperoxidation The concentrations of malondialdehyde (MDA) in the samples were determined by high-performance liquid chromatography (HPLC) (Agilent Technologies 1200 Series; Santa Clara, CA, USA),according to Grotto et al. (2007) 20 using a derivative of thiobarbituric acid (TBA). A standard curve was created using MDA tetrabutylammonium salt at concentrations ranging from 0.5 to 5 μmol/L. The MDA was determined at 532 nm and the results were expressed as umol/L of MDA/milligram protein. Inflammatory Parameter The concentration of tumor necrosis factor-alpha (TNF- α ) was assessed by enzyme-linked immunosorbent assay (ELISA) according to the manufacturer’s recommendations (ThermoFisher Scientific, cat.KMC3011). The results were expressed in pg/mg of protein. Statistical analysis Initially, the data were assessed using Grubbs test to verify possible outliers followed by the Shapiro-Wilk normality test, and in both of them the data met the assumptions for the use of parametric tests. Then, the Two-way ANOVA test was performed, followed by the Bonferroni post-hoc test when necessary. For analysis of the ITT data (table 2), the one-way variance test (one-way ANOVA) of repeated measures was performed, followed by post-hoc Tukey test when necessary. The level of significance was set at p < 0.05. The Graph Pad Prism software, version 5, was used as the statistical package. All data were expressed as mean and standard deviation, except for figure 1A, expressed as mean and standard error of mean. Results Body weight and insulin resistance The RE had a beneficial effect, preventing the DIO + RE group from continuing to gain weight even with the HFD consumption, not characterizing weight loss, but rather weight maintenance, even without food intake control (Figure 1A-C). The pre-exercise ITT showed that the DIO animals had insulin resistance (p > 0.05) (Table 2). The results demonstrated that HFD can lead to a loss of glucose uptake even with an external insulin stimulus (2U/kg body weight). The RE (p < 0.05), even with HFD intake, was able to delay the progression of the disease, maintaining a better glucose decay rate when compared to the sedentary DIO group (p < 0.01). There was no significant difference between pre- and post‑exercise in any group (Figure 1D). DCFH oxidation DCFH oxidation levels were measured as indicators of the reactive species production, especially hydrogen peroxide, and the results showed that in untrained animals, DIO caused an increase in DCF levels (p < 0.001) in comparison to animals with SD. HFD-fed animals submitted to resistance training (DIO + RE) showed a significant decrease in DCF levels compared to the DIO group (p < 0.01) (Figure 2A). Lipoperoxidation As shown in Figure 2B, MDA levels suggest an increase in lipoperoxidation in DIO animals (p < 0.05), with reversion of the condition (p < 0.05) with resistance training (DIO + RE). SOD Activity The results observed in Figure 2C show that DIO did not alter SOD activity, but resistance training was able to increase its activity in the SD + RE group (p < 0.05), an increase not observed when exercise was performed in the obese group. 547