Table 1.
Bz therapy ameliorates clinical parameters.
Fig 1.
Infusion with Ang II (2 mg/Kg/day) promotes blood pressure overload in parallel with prolonged QTc.
(A) Representative images of blood flow, SBP (green line) and DBP (blue line) in Sal-infused and Ang II-infused C57BL/6 mice, at 7 dps. (B) The graph shows systolic blood pressure (SBP) in Sal-infused and vehicle (Veh) and losartan (Los) treated Ang II-infused C57BL/6 mice. Mice were analyzed at 7 (pre-therapy), 14 and 28 dps. (C) Representative images of the ventricular chamber of Sal- and Ang II-infused mice, at 28 dps. Graphs show FAC% and LVEF%, evaluated according to Simpson’s method. (D) Representative images of the 3D ECG tracing recorded at 14 and 28 dps. (E) Graphs show heart rate (beats per minute, bpm), PR interval duration (ms), and QTc interval (ms), at 28 dps. (F) The graph shows QTc interval (ms) evaluated 30 days after the end of the Ang II infusion (58 dps). Data are shown as means ± SD. **, p < 0.01, ***, p < 0.001, Sal vs Ang II + Veh; ###, p < 0.001, Ang II + Veh vs AngII + Los (test: ANOVA, post-test: Tukey’s multiple comparisons).
Fig 2.
Effect of Bz therapy after Ang II infusion (2 mg/Kg/day) on pressure overload.
(A) The graph shows the mean blood pressure (MBP) in Sal-infused, Veh-treated, and Bz-treated Ang II-infused C57BL/6 mice analyzed at 7 (pre-therapy), 14, and 28 dps. (B) Representative images of blood flow and systolic blood pressure (SBP, green line) and diastolic blood pressure (DBP, blue line), at 21 dps and 28 dps. Data are shown as means ± SD. *, p < 0.05, ***, p < 0.001, comparison with Sal-infused mice; #, p < 0.05, Ang II + Veh vs Ang II + Bz (test: ANOVA, post-test: Tukey’s multiple comparisons).
Fig 3.
Effects of Bz therapy on heart rate and cardiac electrical activity.
(A) Heart rate (bpm) in Ang II-infused mice treated with Veh or Bz compared with day 0 (pre-surgery) and saline-infused group (control), at 14 and 28 days post-osmotic minipump implantation. (B) Representative images of the 2D and 3D tracings of ECG records of saline-infused, Veh-treated, and Bz-treated Ang II-infused C57BL/6 mice analyzed at 14 and 28 dps. Data are shown as means ± SD. &&& p < 0.001, day 0 vs Ang II + Veh; * p < 0.05, Sal vs Ang II + Veh (test: ANOVA, post-test: Tukey’s multiple comparisons).
Fig 4.
Bz therapy restores the Ang II-induced prolonged QTc interval.
(A) Representative images of 2D tracings of ECG records indicating the start and end points (indicated with arrows and dashed red lines) used for QT interval measurement in C57BL/6 mice infused with saline or Ang II, treated with Veh or Bz, analyzed at 28 dps. (B) Representative profiles of RR interval duration (ms) registered in sequential heart beats, at 28 dps. (C) QRS complex duration (ms) in Veh-treated and Bz-treated Ang II-infused mice compared with day 0 (pre-surgery) and the Sal control group, at 14 and 28 dps. (D) QTc interval duration (ms) in Veh-treated and Bz-treated Ang II-infused mice compared with day 0 (pre-surgery) and the Sal control group, at 14 and 28 dps. Data are shown as means ± SD. & p < 0.05, &&& p < 0.001, day 0 vs Ang II; * p < 0.05, *** p < 0.001, Sal vs Ang II; # p < 0.05, Veh-treated vs Bz-treated Ang II-infused (test: ANOVA, post-test: Tukey’s multiple comparisons).
Table 2.
ECHO parameters analyzed at 28-days post-surgery.
Fig 5.
The cardiac function and structure were preserved in benznidazole-treated Ang II-infused mice.
(A) Representative images of hearts and graphs showing their dimensions (a, b, and c axis), at 28 dps. (B) Representative images of hearts and relative heart weights, at 28 dps. (C) Representative images of the cardiac ventricular chamber visualized by ECHO analysis, at 28 dps. (D) FAC% and LVEF%, at 28 dps. (E) Right ventricular (RV), left ventricular (LV) areas and internal dimension of the ventricles (LVID), at 28 dps. Data are shown as means ± SD. *, p < 0.05, **, p < 0.01, Sal-infused vs Veh-treated Ang II-infused group (test: t-Student; ANOVA, post-test: Tukey’s multiple comparisons).
Fig 6.
Effect of Bz therapy on ROS production in the cardiac tissue of Ang II-infused mice.
(A) A commercial assay kit in ventricle extracts of the studied groups detected concentrations of NADP/NADPH. (B) Graphs show fluorescence intensity (pixel) and area marked by the DHE probe in cardiac tissue. (C) Representative sections of ventricles stained with the ROS probe DHE. Data are expressed as means ± SD. ***, p < 0.001, Sal vs Ang II infusion; ### p < 0.001, Ang II + Veh vs Ang II + Bz (test: ANOVA, post-test: Tukey’s multiple comparisons). Bars = 100 µm.
Fig 7.
Beneficial effects of Bz on long-QTc were correlated with amelioration of inflammation and antioxidant/oxidant imbalance in cardiac tissue of Ang II-infused mice.
(A) The graph shows the correlation of QTc interval dispersion (ms) with IL-6 concentrations (pg/mL) in ventricle extracts. (B) The graph shows the correlation of QTc interval dispersion (ms) with TBARS levels (OD) in ventricle extracts. (C) The graph shows the correlation of QTc interval dispersion (ms) with SOD concentrations (U/mg of tissue) in ventricle extracts. Each dot represents a mouse sample. Ellipses identify groups of mice; color code: blue, saline; magenta, Ang II + Veh; green, Ang II + Bz (Test: Pearson correlation coefficient and two-tailed).
Fig 8.
Bz therapy improves pressure overload and QTc interval dispersion by restoring antioxidant/oxidant balance.
(A) The graph shows the antioxidant/oxidant ratio (ratio = SOD activity/ TBARS levels) expressed as fold change. (B) The graph shows the correlation of QTc interval prolongation (ms) with SBP (mmHg). (C) The graph shows the correlation of QTc interval dispersion (ms) with the antioxidant/oxidant ratio. Each dot represents a mouse sample. Ellipses identify groups of mice; color code: blue, saline; magenta, Ang II + Veh; green, Ang II + Bz (Test: Pearson correlation coefficient and two-tailed).