Intermittent dobutamine administration mimicked exercise‐induced cardiac phenotype and protected against left ventricular acute pressure overload

Abstract

The aim of the present study was to address if the submission to a stimuli that mimicked the intermittent cardiac overload imposed by exercise training, would result in a comparable cardioprotective phenotype. Male Wistar rats were submitted to treadmill running (Ex,n=20), dobutamine (Dob; 2mg/kg,s.c.,n=20) or placebo administration (Cont,n=20) for 5 days/week during 8 weeks. After that, half were sacrificed for histological and biochemical analysis and half were submitted to hemodynamic evaluation at baseline and during 2 hours of left ventricular acute pressure (LVP) overload (35% increase in LVPmax). Both Ex and Dob showed cardiac hypertrophy with normal MHC isoforms, fibrosis, osteopontin‐1 and calcineurin protein levels. Moreover, they presented increased SERCA2a and phospho Akt/mTOR protein levels. Both Ex and Dob protected from cardiac dysfunction induced by acute LVP overload. These data suggest that chronic submission to intermittent cardiac overload induced by dobutamine provides a cardioprotective phenotype resembling exercise training.