Cardiac Characterization Of Sgca-Null Mice Using High Resolution Echocardiography

Limb-girdle muscular dystrophy 2D (LGMD2D) is an inherited myogenic disorder belonging to the group of muscular dystrophies. Sgca-null mouse is a knock-out model of LGMD2D. Little is known about cardiac phenotype characterization in this model at different ages. We conducted a prospective study to characterize cardiac sgca-null mice phenotype using high resolution Doppler echocardiography at different ages. Conventional echocardiography was performed on anesthetised mice using a Vevo 770 (Visualsonics) with 30 MHz cardiac probe. Wild Type (WT) and sgcanull mice were scanned at 13, 15 and 17 months. From M-mode, we measured interventricular septal (IVS) wall thickness, posterior wall (PW) thickness, and end-left ventricular diameter in systolic and diastolic. From the above parameters, we calculated left ventricular (LV) shortening fraction (SF), LV ejection fraction (EF) and LV mass. At age 13 months, PW diastolic thickness was increased in sgca-null mice (0.89 +/- 0.14 mm vs 0.73 +/- 0.2 mm; P= 0.020) and LV mass was higher in sgcanull mice (LV mass 205.2 mg vs 143 mg; P= 0.001). We found also dilation of the LV (LVEDD: 4.84 mm vs 4.29 mm; P= 0.019) in sgca-null mice. At age 15 months, dilation of the LV (LVEDD: 4.86 mm vs 4 mm; P= 0.05) with an increase of the LV mass (165.7 mg vs 127.12; P= 0.03) are found in sgca-null mice. At age 17 months, we found a decrease of the PW thickening (17% vs 30%; P= 0.036). This work provides echocardiographic insights for the assessment of pharmaceutical therapies in sgca-null mice.