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. 2007 Nov-Dec;1(6):393-9.
doi: 10.1016/j.jash.2007.09.001.

Exercise training prevents development of cardiac contractile dysfunction in hypertensive TG (mREN-2)27 rats

R Tyler Morris  1 , Deborah M Fine, Simon J Lees, Frank W Booth, C Daniel Link, Carlos M Ferrario, Craig S Stump, James R Sowers
Affiliations

Exercise training prevents development of cardiac contractile dysfunction in hypertensive TG (mREN-2)27 rats

R Tyler Morris et al. J Am Soc Hypertens. 2007 Nov-Dec.

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.

Methods and 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.

Conclusion: 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.

Keywords: Hypertension; exercise; heart.

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Figures

Figure 1
Figure 1
Effect of exercise training on resting cardiac output (ml/min) normalized to body weight (g) [cardiac index] in 8-wk-old Sprague-Dawley (SD) and Ren-2 rats. * indicates for main effect (p < 0.05) of exercise within SD and Ren-2 by 2-way ANOVA. Values for each group are mean ± SEM with n = 5 / group.
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References

    1. Campbell DJ, Rong P, Kladis A, Rees B, Ganten D, Skinner SL. Angiotensin and bradykinin peptides in the TGR(mRen-2)27 rat. Hypertension. 1995;25:1014–1020. - PubMed
    1. Chiariello M, Ambrosio G, Cappelli-Bigazzi M, Perrone-Filardi P, Brigante F, Sifola C. A biochemical method for the quantitation of myocardial scarring after experimental coronary artery occlusion. J Mol Cell Cardiol. 1986;18:283–290. - PubMed
    1. Chomczynski P, Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987;162:156–159. - PubMed
    1. Depre C, Shipley GL, Chen W, Han Q, Doenst T, Moore ML, Stepkowski S, Davies PJ, Taegtmeyer H. Unloaded heart in vivo replicates fetal gene expression of cardiac hypertrophy. Nat Med. 1998;4:1269–1275. - PubMed
    1. Diffee GM, Seversen EA, Titus MM. Exercise training increases the Ca(2+) sensitivity of tension in rat cardiac myocytes. J Appl Physiol. 2001;91:309–315. - PubMed

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