Article Title



Muscular dystrophy (MD) is an incurable degenerative disease in which cardiomyopathy is a primary cause of death. Mouse models are employed in the early development of many new treatments for MD. The DBA/2-congenic Dmdmdx (“D2”) mouse is a novel dystrophic model that heretofore is uncharacterized for cardiopathological representation of MD. Purpose: We examined whether MD-associated cardiopathologies were present in 4-month old D2 mice (n=10) compared to age matched controls (“D2J” mice n=10). METHODS: Anesthetized mice were examined by cardiac echocardiography using a Visual Sonics Vivo770 device with a high frequency (30 MHz) transducer. 2-dimentional B-mode and M-mode scans were performed to obtain parasternal long and short axis (obtained at mid ventricle as confirmed by papillary muscle visualization) cardiac images. Key dependent measures included cardiac output (CO), stroke volume (SV), percent ejection fraction (%EF), percent fractional shortening (%FS), and left ventricular mass (LVmass). RESULTS: Blinded analyses revealed that at 4 months of age, the D2J and D2 dystrophic mouse strains exhibited similar cardiac performance values. Specifically, CO (D2J 13.2 ± 3.4 ml/min, D2 15.6 ± 5.2 ml/min; p=0.255), SV (D2J 29.2 ± 7.1 µl, D2 34.5 ± 12.4 µl; p=0.110), %EF (D2J 0.65 ± 0.13, D2 0.63 ± 0.10; p=0.250), %FS (D2J 0.42 ± 0.07, D2 0.43 ± 0.14; p=0.269), and LVmass (D2J 141 ± 29 mg, D2 161 ± 40 mg; p=0.376) were statistically similar. CONCLUSIONS: As with many other dystrophic mouse strains, findings indicated that no physiologic differences were observed between young dystrophic D2 mice as compared to normal D2J control mice. Future investigations should examine D2 mice in a longitudinal fashion in order to understand if and when physiologic declines in heart function occur and whether potential changes are associated with histological alterations characteristic of MD.

Supported by: Parent Project Muscular Dystrophy to JS and JQ

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