Efeitos do Carvedilol na hipertrofia ventricular esquerda de ratos espontaneamente hipertensos

Abstract

Cardiac hypertrophy is a major mechanism by which the heart compensates for chronic conditions of overload, is a feature of hypertension. Carvedilol is a not seletive alpha and beta adrenergic blocker which acts on cardiac hypertrophy (HC) with hypotensive effects. The present stydy has the objective to verify the effects of carvedilol on HC of SHR rats. We used 14 each: SHR and Wistar rats. Animals were divided into two subgroups with seven animals: SHR-Drug (SHR-M), SHR-control (SHR-C) Normal-Drug (N-M) and Normal-Control (N-C). SHR-M and N-M received 5mg/kg of carvedilol by gavage while controls received only water for 4 weeks. We compared the body weight (BW), blood pressure (BP) and heart rate (HR) at the beginning and at end of the experiment. and, finally, heart and left ventricular weight (LV). We measured the cardiac hypertrophy estimating the heart and left ventricular weight, transverse diameter of ventricular cardiomyocytes and collagen. Student t test, ANOVA and Kruskal Wallis were used in statistical analyse. The BW increased in all groups, the final weight of SHR-C body weight was lower than the N-C. BP was not reduced by carvedilol; BP of SHR-C was higher than N-C. Total weight of the heart has not decreased, the LV weight was greater in SHR-C when compared to the N-C and in SHR-M when compared to N-M. The transverse diameter of cardiomyocytes was greater in SHR-F and SHR-C. The amount of collagen remained unchanged. In conclusion, in SHR, carvedilol is not able to reduce BP, HR, heart weight and left ventricular weight. The LV weight was greater in SHR. The transverse diameter of cardiomyocytes was greater in SHR and remained unchanged with carvedilol that does not alter the left venricular amount of collagen in those animals.