Transverse Aortic Constriction (TAC)
Experimental Protocol
The TAC model is induced surgically, and cardiac remodeling is monitored at specific timepoints during the study. A non-invasive echocardiogram is performed at 24 hours, 2 weeks, and 6 weeks post- TAC. A live pressure-volume loop is obtained at 6 weeks followed by final measurements, sample collection, and histology.
Histology
Figure 1. Cardiac remodeling and left ventricle fibrosis via Masson’s trichrome staining in TAC mice. (A) SHAM heart at 10x magnification; left ventricle magnification at 400x. (B) TAC heart at 10x magnification, left ventricle magnification at 400x.
Cardiac and Pulmonary Remodeling
Figure 2: (A) Cardiac remodeling in the TAC mice,*: p < 0.001, TAC vs. SHAM. (B) Pulmonary remodeling in the TAC mice, *: p < 0.05, TAC vs. SHAM.
Mouse Echocardiography
Table 1. Echocardiogram parameters 24 hours after surgery, 2 weeks after surgery, and 6 weeks after surgery in the SHAM and TAC groups.
Abbreviations: IVSd, Interventricular Septum Thickness at end Diastole; LVEDd, Left-Ventricular End-Diastolic Dimension; LVPTd, Left-Ventricle Posterior Wall Thickness Diastole; IVSs, Interventricular Septum Thickness at end Systole; LVESd, Left-Ventricular End-Systolic Dimension; LVPTs, Left-Ventricle Posterior Wall Thickness Systole; HR, Heart Rate; FS, Fractional Shortening; EF, Ejection Fraction; LVM, Left Ventricular Mass; TAPSE, Tricuspid Annular Plane Systolic Excursion. All parameters are expressed as means ± SD. The P value was calculated by comparing the 6- week echo between the SHAM and TAC mice.
Mouse LV Pressure-Volume Catheterization
Table 2. Left ventricular pressure-volume parameters (open chest) in the SHAM and TAC groups.
Abbreviations: SW, Stroke Work; CO, Cardiac Output; SV, Stroke Volume; Vmax, Maximum Volume; Vmin, Minimum Volume; Pmax, Maximum Pressure; Pmin, Minimum Pressure; HR, Heart Rate; EF, Ejection Fraction; Ea, Arterial Elastance; dP/dt max, Maximum Derivative of Change in Systolic Pressure Over Time; dP/dt min, Minimum Derivative of Change in Diastolic Pressure Over Time.
