title: Effects of exercise training on cardiac function and myocardial remodeling in post myocardial infarction rats.
abstract: To test the hypothesis that early exercise training after myocardial infarction (MI) could preserve cardiac function, alleviate left ventricular (LV) remodeling and induce a protective effect on morphology, male Sprague-Dawley rats underwent coronary ligation or sham operation, and were assigned to 3 groups: Sham, sedentary MI (SedMI), and exercise MI (ExMI). We measured the changes in collagen volume fraction, matrix metalloproteinase (MMP) 1, tissue inhibitor matrix metalloproteinase 1 (TIMP-1), angiotensin II receptor type 1 (AT1), and angiotensin converting enzyme (ACE) at gene and protein levels after 8 weeks of exercise training. Cardiac functions were determined by echocardiographic and hemodynamic measurements. Early exercise training after MI had no effect on LV wall thinning. Cardiac function was significantly preserved in the ExMI group in comparison to the SedMI group. The collagen volume fraction in the ExMI group was significantly lower than in the SedMI group. Compared to the SedMI group, the ExMI group showed a markedly decrease at both the gene and protein levels in TIMP-1 (P<0.05). No significant differences were found in MMP-1 among the three groups. MMP-1/TIMP-1 ratio in the ExMI group was significantly higher than in the SedMI group. In addition, the expression of AT1 protein in the ExMI group was significantly lower than in the SedMI group. Furthermore, both ACE mRNA expression and ACE binding in the ExMI group are significantly decreased compared to the SedMI group. Our results suggest that early exercise training after MI reduces TIMP-1 expression, improves the balance between MMPs and TIMPs, and mitigates the expressions of ACE and AT1 receptor. These improvements, in turn, attenuate myocardial fibrosis and preserve post-MI cardiac function.
authors.affiliation: Laboratory of Cardiovascular Research, University of Texas at San Antonio, 1 UTSA Circle, San Antonio, TX 78249, USA.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Xu
authors.forename: Wenhan
authors.initials: W
authors.lastname: Wan
authors.forename: Anthony S
authors.initials: AS
authors.lastname: Powers
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.forename: Lisa L
authors.initials: LL
authors.lastname: Ji
authors.forename: Shunhua
authors.initials: S
authors.lastname: Lao
authors.forename: Bryan
authors.initials: B
authors.lastname: Wilson
authors.forename: John M
authors.initials: JM
authors.lastname: Erikson
authors.forename: John Q
authors.initials: JQ
authors.lastname: Zhang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003094:Collagen / Q000378:metabolism; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D024061:Collagen Type III / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation; D006352:Heart Ventricles / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology; D006439:Hemodynamics; D008264:Macrophages / Q000473:pathology; D020781:Matrix Metalloproteinase 1 / Q000235:genetics / Q000378:metabolism; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000201:enzymology / Q000473:pathology / Q000503:physiopathology*; D007703:Peptidyl-Dipeptidase A / Q000235:genetics / Q000378:metabolism; D010805:Physical Conditioning, Animal; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism; D014463:Ultrasonography; D016277:Ventricular Function, Left / Q000502:physiology*; D020257:Ventricular Remodeling / Q000502:physiology*
chemical_list: D024042:Collagen Type I; D024061:Collagen Type III; D044140:Receptor, Angiotensin, Type 1; D019715:Tissue Inhibitor of Metalloproteinase-1; D053773:Transforming Growth Factor beta1; D003094:Collagen; D007703:Peptidyl-Dipeptidase A; D020781:Matrix Metalloproteinase 1