ABC | Volume 110, Nº6, June 2018

Original Article Oishi et al Endothelial dysfunction and blood pressure in rats Arq Bras Cardiol. 2018; 110(6):558-567 3.5 3 2.5 2 1.5 1 0.5 0 6 12 18 24 *+ * * nM CHP/gram of tissue CT HFD Time (Weeks) Figure 5 – Lipid peroxidation in aortic rings from rats of control (CT) and high-fat diet (HFD) groups. *P < 0.05, compared with CT group; + p < 0.05, within-group comparison (0 vs. 6, 6 vs. 12, 12 vs. 18, 18 vs. 24 weeks); seven rats from each group were compared at each time point. CHP: cumene hydroperoxide. CT HFD * * * + 160 150 140 130 120 110 0 6 12 18 24 Time (weeks) Systolic blood pressure (mmHG) Figure 6 – Systolic blood pressure in rats of control (CT) and high-fat diet (HFD) groups over 24 weeks. *P < 0.05, compared with CT group; + p < 0.05, within-group comparison (0 vs. 6, 6 vs. 12, 12 vs. 18, 18 vs. 24 weeks); seven rats from each group were compared at each time point Our findings are consistent with literature, showing that a high-fat diet treatment for 6 weeks was able to increase VAT. Interestingly, an inverse correlation was observed between VAT and endothelium function (pD 2 ). In addition, the levels of these adipokines were altered at 6 weeks in the HFD group, confirming the concept of obesity-related endothelial dysfunction. We showed here that these events occur at an early stage of obesity development. Obesity is also strongly associated with hypertension, which is a major risk factor for the development of coronary heart diseases. In fact, 79% of hypertension in men was a direct result of excess weight. 33 Hypertension, characterized by chronic high blood pressure, has a multifactorial origin and an endothelial dysfunction can contribute to its genesis and maintenance. 5 In the present study, the high-fat diet induced an increase in the SBP at 12 weeks and it continued to increase reaching the maximum values at 18 weeks. These results are in accordance with Boustany et al. 34 that observed a rise in blood pressure, and increased activity of adipose and systemic renin angiotensin system after 11 weeks of high-fat diet in rats. The Framingham Heart Study reported a close connection between body fat levels and blood pressure in both men and women, and that adiposity emerged as a major factor which can be controlled and that contributes to hypertension. 34 The same occurred in our study, which showed a strong correlation between SBP and VAT. Interestingly, in the present study, structural alterations in the aorta occurred after a rise in blood pressure. It is well known that hypertension is associated with structural alterations in arteries that could contribute to maintaining hypertension. 35 In addition, although not significantly, the media/lumen ratio starts to increase at 12 weeks, coinciding with the rise of blood pressure, and at 18 and 24 weeks, this increase becomes 564