Myocardial fibrosis rather than hypertrophy induces diastolic dysfunction in renovascular hypertensive rats

Myocardial fibrosis rather than hypertrophy induces diastolic dysfunction in renovascular hypertensive rats

Autor Matsubara, L. S. Google Scholar
Matsubara, B. B. Google Scholar
Okoshi, M. P. Google Scholar
Franco, M. Autor UNIFESP Google Scholar
Cicogna, A. C. Google Scholar
Instituição UNESP
Universidade Federal de São Paulo (UNIFESP)
Resumo The aim of the present study was to evaluate the-effect of interstitial fibrosis alone or associated with hypertrophy. on diastolic myocardial function in renovascular hypertensive rats. Myocardial function was evaluated in isolated papillary muscle from renovascular hypertensive Wistar rats (RHT, n = 14), renovascular hypertensive rats treated with the angiotensin converting enzyme inhibitor (ACEI) ramipril, 20 mg.kg(-1).day(-1) (RHT RAM, n = 14), and age-matched unoperated and untreated Wistar rats (CONT, n = 12). the ACEI treatment for 3 weeks allowed the regression of myocyte mass and the maintenance of interstitial fibrosis. Myocardial passive stiffness was analyzed by the resting tension - length relationship. the myocardial fibrosis was evaluated by measuring myocardial hydroxyproline (Hyp) concentration and by histological studies of the myocardium stained with hematoxylin and eosin or picrosirius red. Left ventricular weight was significantly higher in RHT (0.97 +/- 0.12 g) compared with CONT (0.66 +/- 0.06 g) and RHT RAM (0.69 +/- 0.14 g). the Hyp levels were 2.9 +/- 0.4, 3.4 +/- 0.3, and 3.8 +/- 0.4 mu g/mg of dry tissue for the CONT, RHT, and RHT RAM, respectively. Perivascular and interstitial fibrosis were observed in RHT and RHT RAM groups. There were lymphomononuclear inflammatory exudate and edema around arteries, involving adjacent myocytes in the RHT group. There was an increased passive stiffness in RHT and RHT RAM groups compared with the CONT group. in conclusion, our results indicate that the Impaired diastolic function in the renovascular hypertensive rats is related to interstitial fibrosis rather than to myocardial hypertrophy.
Palavra-chave collagen
passive stiffness
renovascular hypertension
angiotensin converting enzyme inhibitor
papillary muscle
Idioma Inglês
Data de publicação 1997-12-01
Publicado em Canadian Journal of Physiology and Pharmacology. Ottawa: Natl Research Council Canada, v. 75, n. 12, p. 1328-1334, 1997.
ISSN 0008-4212 (Sherpa/Romeo, fator de impacto)
Publicador Natl Research Council Canada
Extensão 1328-1334
Fonte http://dx.doi.org/10.1139/cjpp-75-12-1328
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000072260500009
Endereço permanente http://repositorio.unifesp.br/handle/11600/25817

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