Isoproterenol-induced cardiac hypertrophy is attenuated in CARP Tg mice.

<p>WT and CARP Tg mice were continuously infused with vehicle (100 µmol/L ascorbic acid) or isoproterenol at a rate of 30 mg/kg/day using a subcutaneously implanted mini-osmotic pump. After 14 days, mice were sacrificed for assessment of cardiac hypertrophy. (A) Representative examples of M-mode echocardiograms of hearts from WT and CARP Tg mice infused with isoproterenol (ISO) or vehicle (sham). (B) The ratio of heart weight to body weight (HW/BW). (C) The ratio of heart weight to tibia length (HW/TL). (D) Staining of hearts from WT and CARP Tg mice infused with ISO or vehicle. <i>Upper panel:</i> Gross heart morphology; <i>middle panel:</i> H&E-stained longitudinal sections; <i>lower panel:</i> PSR-stained sections. (E) H&E staining of sections from the left ventricular myocardia of WT and CARP Tg mice infused with ISO or vehicle. Scale bar = 20 µm. (F) Quantification of cross-sectional areas in the cardiomyocytes shown in (E). (G) Quantification of collagen areas in the myocytes shown in (D). (H) Changes in the expression levels of mRNAs transcribed from the ANF, β-MHC, and α-actin genes after infusion of isoproterenol in WT and CARP Tg mice. mRNA expression levels were quantitated using real-time PCR.