Changes in body weight (BW) during 15 weeks of experimental protocol after the initiation of obesity at week 3.

<p>Data presented as the mean ± SD. * p<0.05 <i>versus</i> C. Two way ANOVA for independent samples and Bonferroni’s post-hoc analysis.</p

(A) Glucose tolerance profile, (B and D) hormone serum levels and (C) homeostatic model assessment index (HOMA-IR).

<p>Control (C; n = 20) and obese (Ob; n = 17) groups. n = number of animals. (A) Data presented as the means ± standard deviation; Two way ANOVA for independent samples and Bonferroni’s <i>post-hoc</i> analysis. (B, C and D) Values shown are median ± interquartile range; Mann-Whitney test. *p<0.05 <i>versus</i> C.</p

(A, B and C) Post-rest contraction (PRC) and (D, E and F) effects of increasing extracellular Ca²⁺ concentration in papillary muscles from control (white bars) and obese rats (cross-hatched bars).

<p>Baseline calcium concentration (0.5 mM) is presented as 100%. Maximum developed tension normalised per cross-sectional area [DT, g/mm²] and positive [+dT/dt, g/mm²/s] and negative [-dT/dt, g/mm²/s] tension derivative normalized per cross-sectional area of the papillary muscle. Data presented as the mean percent of baseline ± standard deviation.*p < 0.05 <i>versus</i> C. Repeated-measures two-way ANOVA and Student-Newman-Keuls <i>post-hoc t</i>est.</p

Baseline data from isolated muscle preparation.

<p>Values expressed as mean ± SD. n = number of animals. C: control; Ob: obese; Baseline condition: 2.5 mM [Ca²⁺]. DT: maximum developed tension normalized per cross-sectional area of the papillary muscle; RT: resting tension normalized per cross-sectional area of the papillary muscle; peak of the positive (+dT/dt) and negative (-dT/dt) tension derivatives normalized per cross-sectional area of the papillary muscle; CSA: cross-sectional area. Student’s t-test for independent samples.</p><p>Baseline data from isolated muscle preparation.</p

Cardiac, Metabolic and Molecular Profiles of Sedentary Rats in the Initial Moment of Obesity

<div><p>Abstract Background: Different types of high-fat and/or high-energy diets have been used to induce obesity in rodents. However, few studies have reported on the effects observed at the initial stage of obesity induced by high-fat feeding on cardiac functional and structural remodelling. Objective: To characterize the initial moment of obesity and investigate both metabolic and cardiac parameters. In addition, the role of Ca2+ handling in short-term exposure to obesity was verified. Methods: Thirty-day-old male Wistar rats were randomized into two groups (n = 19 each): control (C; standard diet) and high-fat diet (HF, unsaturated high-fat diet). The initial moment of obesity was defined by weekly measurement of body weight (BW) complemented by adiposity index (AI). Cardiac remodelling was assessed by morphological, histological, echocardiographic and papillary muscle analysis. Ca2+ handling proteins were determined by Western Blot. Results: The initial moment of obesity occurred at the 3rd week. Compared with C rats, the HF rats had higher final BW (4%), body fat (20%), AI (14.5%), insulin levels (39.7%), leptin (62.4%) and low-density lipoprotein cholesterol (15.5%) but did not exhibit alterations in systolic blood pressure. Echocardiographic evaluation did not show alterations in cardiac parameters. In the HF group, muscles were observed to increase their +dT/dt (C: 52.6 ± 9.0 g/mm2/s and HF: 68.0 ± 17.0 g/mm2/s; p < 0.05). In addition, there was no changes in the cardiac expression of Ca2+ handling proteins. Conclusion: The initial moment of obesity promotes alterations to hormonal and lipid profiles without cardiac damage or changes in Ca2+ handling.</p></div

(A, B and C) Effects of increasing isoproterenol concentration in papillary muscles (10^<i>−7</i> to 10⁻⁵ M) and (D, E and F) protein expression of β-adrenergic receptors (β-AR) and stimulatory G-protein (G_sα) from control (white bars) and obese rats (cross-hatched bars).

<p>Baseline calcium concentration (1.0 mM) is presented as 100%. Maximum developed tension normalised per cross-sectional area [DT, g/mm²] and positive [+dT/dt, g/mm²/s] and negative [-dT/dt, g/mm²/s] tension derivative normalized per cross-sectional area of the papillary muscle. D: β₁AR, E: β₂AR and F: G_sα. (A, B and C) Data presented as the mean percent of baseline ± standard deviation; Repeated-measures two-way ANOVA and Student-Newman-Keuls <i>post-hoc</i> test. (D, E and F) Values shown are mean ± standard deviation; Student’s t-test for independent samples (D, E and F).*p < 0.05 <i>versus</i> C.</p

Systolic blood pressure, lipid profile and cardiac morphology

<p>Data presented as means ± SD. control (C) and obese (Ob) groups; n: animals numbers; Systolic blood pressure and lipid profile (<i>n</i> = 7 animals); SBP: systolic blood pressure; TG: triglycerides; T-Chol: total cholesterol; HDL: high-density lipoprotein; LDL: Low-density lipoprotein. Cardiac parameters <i>(C</i>, <i>n = 20; Ob</i>, <i>n = 17)</i>; HW: heart weight; LVW: left ventricle weight;</p><p>*p<0.05 versus C; Student’s t-test for independent samples.</p><p>Systolic blood pressure, lipid profile and cardiac morphology</p