Alterações histológicas do miocárdio, rim e fígado de ratos (Rattus novergicus) Wistar submetidos à infusão de angiotensina II: influência na função ventricular esquerda e resposta ao tratamento com losartan e carvedilol
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Data
2001
Autores
Vailati, Maria do Carmo Fernandez [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Um aspecto pouco explorado na literatura, é o caráter sistêmico das alterações vasculares induzidas pela angiotensina II (AII). Teoricamente, todos os tecidos podem ser afetados, visto que os receptores da AII já foram identificados em vários órgãos. Os trabalhos que avaliam o efeito da AII no miocárdio são concordantes no sentido de indicar lesões envolvendo vasos e tecido muscular. Não encontramos qualquer estudo que avaliasse o impacto dessas lesões na função ventricular, numa fase que precede a fibrose miocárdica. Foram utilizados 65 ratos Wistar, machos, com aproximadamente 250g de peso corpóreo, divididos em quatro grupos: controle (n=16), ratos tratados com AII (n= 17), ratos tratados com AII + carvedilol (90 mg/kg/dia; n = 15) e AII + losartan (30 mg/kg/dia; n = 17). A infusão contínua de AII foi realizada na dose de 150 hg/min, através de mini-bombas osmóticas colocadas no subcutâneo no dorso do animal. O registro das pressões arteriais caudais (PA) dos animais de cada grupo foi obtido, aproximadamente, 24h antes da implantação da minibomba e antes da realização da eutanásia. Foram realizados cortes histológicos de miocárdio, rim e fígado para coloração pela hematoxilina-eosina e observação das áreas de necrose. A intensidade das lesões foi definida por meio de escores. Uma parte dos animais foi destinada ao estudo histológico e a outra ao estudo do coração isolado. Também foi realizada a técnica de imunohistoquímica para identificação de macrófagos e a técnica vermelho-congo azul de toluidina para mastócitos e eosinófilos. A função ventricular foi avaliada no coração isolado (preparação de Langendorff). Os resultados foram comparados com os ratos do grupo controle, sem qualquer tratamento, por meio de ANOVA com nível de significância p<0,05...
The systemic aspect of vascular damage induced by angiotensin II (AII) is poorly explored in the literature. Considering the presence of AII in various organs, all these tissues might be affect by of AII. There is an agreement among the authors in relation to the effects of AII on the myocardium as involving vessels and myocytes. There is no published data regarding the impact of these lesions on ventricular function preceeding myocardial fibrosis. Sixty five male Wistar rats, (250 ± 20g) distributed in four groups were used: control (n=16), treated with AII (n=17), with AII + carvedilol (90 mg/kg/d, n=15) and AII+ losartan (30 mg/kg/d, n=17). AII was infused continuously at 150 hg/min (for 72 hs) by subcutaneous osmotic pumps. Tail cuff blood pressure was recorded 24 hours before the mini-pump implantation and before euthanasia. Histological sections of the myocardium, kidney and liver were stained by haematoxylin and eosin and observed for presence of necrosis. The injury intensity was scored. Immunohistochemistry was used for macrophages identification and congo red toluidine blue for identification of mast cells and eosinophils. The ventricular function was evaluated in the isolated heart (Langendorff preparation). The results were compared with untreated control rats, by ANOVA and the statistical significance was set at p<0,05. Blood pressure was higher in the groups AII and AII + carvedilol compared to control (165 ± 30 mmHg e 181± 35 mmHg vs 126 ± 13 mmHg, p<0,01). Losartan prevented hypertension. Histopathological analysis showed perivascular inflammation and necrosis of arteriolar wall in the myocardium, kidney, and liver. Carvedilol and losartan partially protected the organs. The intensity of tissular lesions was less than the vascular lesions, without statistical difference among the groups. There were macrophages and mast... (Complete abstract, click electronic address below)
The systemic aspect of vascular damage induced by angiotensin II (AII) is poorly explored in the literature. Considering the presence of AII in various organs, all these tissues might be affect by of AII. There is an agreement among the authors in relation to the effects of AII on the myocardium as involving vessels and myocytes. There is no published data regarding the impact of these lesions on ventricular function preceeding myocardial fibrosis. Sixty five male Wistar rats, (250 ± 20g) distributed in four groups were used: control (n=16), treated with AII (n=17), with AII + carvedilol (90 mg/kg/d, n=15) and AII+ losartan (30 mg/kg/d, n=17). AII was infused continuously at 150 hg/min (for 72 hs) by subcutaneous osmotic pumps. Tail cuff blood pressure was recorded 24 hours before the mini-pump implantation and before euthanasia. Histological sections of the myocardium, kidney and liver were stained by haematoxylin and eosin and observed for presence of necrosis. The injury intensity was scored. Immunohistochemistry was used for macrophages identification and congo red toluidine blue for identification of mast cells and eosinophils. The ventricular function was evaluated in the isolated heart (Langendorff preparation). The results were compared with untreated control rats, by ANOVA and the statistical significance was set at p<0,05. Blood pressure was higher in the groups AII and AII + carvedilol compared to control (165 ± 30 mmHg e 181± 35 mmHg vs 126 ± 13 mmHg, p<0,01). Losartan prevented hypertension. Histopathological analysis showed perivascular inflammation and necrosis of arteriolar wall in the myocardium, kidney, and liver. Carvedilol and losartan partially protected the organs. The intensity of tissular lesions was less than the vascular lesions, without statistical difference among the groups. There were macrophages and mast... (Complete abstract, click electronic address below)
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Coração - Fisiopatologia - Estudos experimentais, Histological lesions, Arterial hypertension
Como citar
VAILATI, Maria do Carmo Fernandez. Alterações histológicas do miocárdio, rim e fígado de ratos (Rattus novergicus) Wistar submetidos à infusão de angiotensina II: influência na função ventricular esquerda e resposta ao tratamento com losartan e carvedilol. 2001. 98 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2001.