A modified model of cardiac reverse remodeling following abdominal aortic banding and debanding in rats

Figures

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  FIGURE 1. Aortic banding procedure. (a) The medical film, 2–0 silk thread and 22G blunted needle were used for the medical film-supported abdominal AB procedure. (b) AB procedure was performed in midline laparotomy and the abdominal aorta was clearly dissected and visible. Then the medical film-supported silk thread was placed around the prepared abdominal aorta. (c) Made a complete wrap of medical film around abdominal aorta, placed the 22G blunted needle on medical film. (d, e) Used the silk thread banding the abdominal aorta and then carefully and quickly removed the needle.

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  FIGURE 2. Aortic debanding procedure. (a) DB procedure was performed in midline laparotomy and the thread left behind by the ligature was identified. (b) Under a dissecting microscope, the threads were carefully traced to the binding site of abdominal aorta. (c, d) The reactive fibrotic tissue was carefully and thoughtfully stripped and the banded silk on the medical film was removed.

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  FIGURE 3. Experimental protocol design and abdominal aortic flow. (a) Experimental protocol design. (b) Visualization of the abdominal aorta in rats by echocardiography after AB and DB operation. The arrow showed the constriction and relieved constriction on the abdominal aorta in AB and DB rats. Color Doppler echocardiographic images showed blood flow of abdominal aorta. Continuous-wave Doppler echocardiographic images illustrated PSVst and PSVpro. (c–e) Quantitative results of the PSVst, MPG and PSVst/PSVpro ratio across the stenotic segment of the abdominal aorta. PSVst, the blood flow velocity at the stenotic segment of the abdominal aorta; PSVpro, the blood flow velocity at the segment proximal to the stenosis of the abdominal aorta; MPG, mean pressure gradient (ordinary one-way ANOVA with Tukey's comparisons test was used for statistical analysis. **P < 0.01, ***P < 0.001. sham: n = 6, AB: n = 40, DB: n = 14).

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  FIGURE 4. AB induced LVH and dysfunction and these effects were reversed by DB. (a) Pulsed-wave Doppler shows the peak early diastolic (E) and late diastolic (A) mitral flow velocity. (b) Pulsed-TDI shows the peak early (E') and late (A') velocities at the septal aspect of the mitral annulus. (c) Representative M-mode echocardiographic images of rats. (d–i) Echocardiography analysis of the E/A, E'/A', EF, FS, LVM, and RWT respectively. EF, ejection fraction; FS, fractional shortening; LVM, left ventricular mass; RWT, relative wall thickness (ordinary one-way ANOVA with Tukey's comparisons test was used for statistical analysis. *P < 0.05, ***P < 0.001, sham: n = 6, AB-4w: n = 29, AB-6w: n = 7, DB-2w: n = 14).

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  FIGURE 5. DB reduces AB-induced elevations in blood pressure, circulating neurohormones, HW/BW and HW/TL (a–c) Non-invasive blood pressure measurement. SBP, systolic blood pressure; DBP, diastolic blood pressure; MAP, mean arterial pressure (sham: n = 6, AB-4w: n = 29, AB-6w: n = 7, DB: n = 14). (d) BNP, B-type natriuretic peptide. (e) ANP, atrial natriuretic peptide. (f) GDF-15, growth differentiation factor 15. (g) Representative heart images of rats (scale bar = 1 cm). (h) HW/BW, heart weight (HW) to body weight (BW) ratio. (i) HW/TL, HW to tibia length (TL) ratio (sham: n = 6, AB-4w: n = 7, AB-6w: n = 7, DB-2w: n = 14) (ordinary one-way ANOVA with Tukey's comparisons test was used for statistical analysis. *P < 0.05, **P < 0.01, ***P < 0.001).

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  FIGURE 6. DB alleviates AB-induced cardiomyocyte hypertrophy and fibrosis. (a) Representative H&E images of CD (scale bar = 100 μm). (b, c) Representative Masson's images of the perivascular fibrosis (scale bar = 100 μm) and interstitial fibrosis (scale bar = 200 μm). (d) Quantitative analysis of the cardiomyocyte diameter. (e) Quantitative analysis of the trichrome-positive area/total area. (f) Quantitative analysis of the PVCA/LA in each group (ordinary one-way ANOVA with Tukey's comparisons test was used for statistical analysis. *P < 0.05, ***P < 0.001, sham: n = 6, AB-4w: n = 7, AB-6w: n = 7, DB-2w: n = 14).

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  FIGURE 7. DB attenuates AB-induced TGF-β1 activation and collagen remodeling. (a) Representative TGF-β1 IHC images of rat hearts (scale bar = 50 μm). (b) Representative polarized light images of Sirius Red staining (scale bar = 50 μm). (c) Quantitative analysis of TGF-β1 IHC staining. (d) Quantitative analysis of collagen I and III from polarized light images. (e) Quantitative analysis of Sirius Red-positive collagen. (f) TGF-β1 mRNA expression levels. (g) CoL1a1 mRNA expression levels. (h) CoL3a1 mRNA expression levels (ordinary one-way ANOVA with Tukey's comparisons test was used for statistical analysis. *P < 0.05, ***P < 0.001, sham: n = 3, AB-4w: n = 3, AB-6w: n = 3, DB-2w: n = 3).