title: Exercise training prevents development of cardiac contractile dysfunction in hypertensive TG (mREN-2)27 rats.
abstract: BACKGROUND
  Angiotensin-II (Ang-II) contributes to cardiac remodeling and left ventricular dysfunction. In contrast, exercise may have beneficial effects on left ventricular structure and function.
  
  
  RESULTS
  We investigated the effects of low-intensity exercise training (ET) on in vivo cardiac function in hypertensive TG (mREN-2)27 rats (Ren-2) which develop left ventricular hypertrophy and dysfunction. Ren-2 rats and Sprague Dawley (SD) controls (4-5 weeks) began treadmill exercise every day for 5-6 weeks. Cardiac function was evaluated by echocardiography. Cardiac output and stroke volume were increased by ET in both 8-wk-old SD and Ren-2. Slope of mitral deceleration time, a non-invasive measure of diastolic function, was lower in the Ren-2 rats, but not changed by ET. LV collagen deposition, as assessed by hydroxyproline assay, was not affected by rat strain or ET at 10-11 weeks of age. Left ventricular B-type natriuretic peptide mRNA levels were higher in the Ren-2 rats (100%), but not affected by ET. Both alpha (~14.5 fold) and beta (~2.5 fold) myosin heavy chain mRNA were higher in the LV of Ren-2 rats (p < 0.05), but were not changed by ET.
  
  
  CONCLUSIONS
  Low-intensity exercise training in Ren-2 rats, a model of Ang-II-mediated hypertension, maintains cardiac index and stroke volume in the presence of impaired diastolic function at 8 wks of age.
authors.affiliation: Department of Medical Pharmacology and Physiology, School of Medicine.
authors.forename: R Tyler
authors.initials: RT
authors.lastname: Morris
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Fine
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Lees
authors.forename: Frank W
authors.initials: FW
authors.lastname: Booth
authors.forename: C Daniel
authors.initials: CD
authors.lastname: Link
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Ferrario
authors.forename: Craig S
authors.initials: CS
authors.lastname: Stump
authors.forename: James R
authors.initials: JR
authors.lastname: Sowers