Remodelação miocárdia e função ventricular em ratos espontaneamente hipertensos observados durante o envelhecimento
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Data
2008-02-22
Autores
Pereira, Elenize Jamas [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A hipertensão arterial sistêmica é uma das principais causas de hipertrofia ventricular. Dados clínicos e experimentais mostram que a hipertrofia ventricular é fator independente de risco cardiovascular associado à maior morbidade. Isto se deve à remodelação cardíaca em resposta a sobrecarga de pressão. Na remodelação cardíaca é observada a hipertrofia ventricular, alteração na matriz extracelular evidenciada por aumento no colágeno intersticial, alteração nos vasos arteriais caracterizada por hipertrofia da camada média da parede vascular e alteração na geometria ventricular. A remodelação ventricular é a causa de disfunção cardíaca que culmina no surgimento da insuficiência cardíaca congestiva. Considerando-se que a hipertensão arterial é importante causa de comprometimento cardiovascular, assim como o envelhecimento é fator que pode levar à insuficiência cardíaca, a nossa hipótese de trabalho é de que a hipertensão arterial é fator aditivo ao envelhecimento para a remodelação cardíaca e disfunção ventricular. O objetivo do trabalho foi avaliar a função cardíaca e a homeostase do cálcio em ratos hipertensos durante o envelhecimento. Foram estudados ratos espontaneamente hipertensos (SHR) e ratos controles não hipertensos (WKY) com idade de 30 semanas (SHR30, n=09 e WKY30, n=10), 45 semanas (n=7) e SHR 45 (n=8), 60 semanas WKY60 (n=8) e SHR 60 (n=11) e 90 semanas WKY90 (n=10) e SRH 90 (n=17). A função cardíaca foi avaliada por meio de coração isolado pela técnica de Langerdorff e a seguintes variáveis foram consideradas: V0 – volume do coração para pressão diastólica de 0mmHg, VE/V0 – relação entre peso do ventrículo esquerdo (VE) e V0 como índices de geometria ventricular.
The hypertension is a major cause of ventricular hypertrophy. Clinical and experimental data showed that ventricular hypertrophy is independent factor for cardiovascular risk associated with higher morbidity. This is due to cardiac remodeling in response to pressure overload. Ventricular hypertrophy increase interstitial collagen, vascular media layer hypertrophy of wall and change in ventricular geometry is observed in cardiac remodeling. The ventricular remodeling is the cause of cardiac dysfunction that culminates in congestive heart failure. Considering that hypertension is a major cause of cardiovascular disease and the aging is factor that can lead to heart failure, we hypothesized that hypertension and aging have an additive efect on cardiac remodeling and ventricular dysfunction. The objective was to assess the ventricular function and mesure the mRNA of protein evolued calcium homeostasis in hypertensive rats during aging. We studied spontaneously hypertensive rats (SHR) and non hypertensive controls rats (WKY) aged 30 weeks (SHR30, n = 09 in WKY30, n = 10), 45 weeks (n = 7) and SHR 45 (n = 8) , 60 weeks WKY60 (n = 8) and SHR 60 (n = 11) and 90 weeks WKY90 (n = 10) and SRH 90 (n = 17). Cardiac function was studied in isolated beating heart according to Langerdorff technique and the following variables were considered: V0 - volume of the heart to diastolic pressure of 0mmHg, VE/V0 - relationship between the left ventricle weight (LV) and V0 as an index of ventricular geometry. The systolic function was evaluated by; + dp/dt, systolic pressure-volume relationship (RPVsist) and systolic stressstrain relationship (R-SSist). The diastolic function was examined by:- dp/dt, ventricular compliance ( V20), measured as diastolic volume necessary to increases diastolic pressure from 0 to 20mmHG and passive stiffness (Stress20), mesured as stress corresponding to strain 20%.
The hypertension is a major cause of ventricular hypertrophy. Clinical and experimental data showed that ventricular hypertrophy is independent factor for cardiovascular risk associated with higher morbidity. This is due to cardiac remodeling in response to pressure overload. Ventricular hypertrophy increase interstitial collagen, vascular media layer hypertrophy of wall and change in ventricular geometry is observed in cardiac remodeling. The ventricular remodeling is the cause of cardiac dysfunction that culminates in congestive heart failure. Considering that hypertension is a major cause of cardiovascular disease and the aging is factor that can lead to heart failure, we hypothesized that hypertension and aging have an additive efect on cardiac remodeling and ventricular dysfunction. The objective was to assess the ventricular function and mesure the mRNA of protein evolued calcium homeostasis in hypertensive rats during aging. We studied spontaneously hypertensive rats (SHR) and non hypertensive controls rats (WKY) aged 30 weeks (SHR30, n = 09 in WKY30, n = 10), 45 weeks (n = 7) and SHR 45 (n = 8) , 60 weeks WKY60 (n = 8) and SHR 60 (n = 11) and 90 weeks WKY90 (n = 10) and SRH 90 (n = 17). Cardiac function was studied in isolated beating heart according to Langerdorff technique and the following variables were considered: V0 - volume of the heart to diastolic pressure of 0mmHg, VE/V0 - relationship between the left ventricle weight (LV) and V0 as an index of ventricular geometry. The systolic function was evaluated by; + dp/dt, systolic pressure-volume relationship (RPVsist) and systolic stressstrain relationship (R-SSist). The diastolic function was examined by:- dp/dt, ventricular compliance ( V20), measured as diastolic volume necessary to increases diastolic pressure from 0 to 20mmHG and passive stiffness (Stress20), mesured as stress corresponding to strain 20%.
Descrição
Palavras-chave
Hipertensão - Fisiopatologia - Estudos experimentais, Coração - Hipertrofia
Como citar
PEREIRA, Elenize Jamas. Remodelação miocárdia e função ventricular em ratos espontaneamente hipertensos observados durante o envelhecimento. 2008. 63 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2008.