Lesões hepáticas de bovinos intoxicados experimentalmente por Senecio brasiliensis (Compositae): estudo semi-quantitativo e quantitativo da matriz extracelular e de células sinusoidais
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Data
2003
Autores
Torres, Márcia Bersane Araújo de Medeiros [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A matriz extracelular hepática (MEC) é atualmente alvo de diversos estudos em modelos de intoxicação experimental e lesões hepáticas crônicas, devido ao seu papel relevante nesses processos. Na espécie bovina, não existem estudos sobre os componentes da MEC hepática normal e nas lesões crônicas os enfoques têm sido os hepatócitos, com apresentações descritivas das alterações da matriz. Por esse motivo propusemos um modelo iniciando com estudo de fígados normais (controle) obtidos dos animais antes do início da intoxicaçãp experimental por Senecio brasiliensis. Esta planta contém alcalóides pirrolizidínicos (APs), que são substâncias causadoras de lesão hepática crônica progressiva. Este trabalho tem como principais objetivos fazer uma avaliação semi-quantitativa e quantitativa de componentes da MEC de fígado normal e de suas alterações durante a progressão da lesão hepática por intoxicação crônica por APs na espécie bovina. Foram usados 5 animais, intoxicados com folhas dessecadas de S. brasiliensis na dose de 0,38g/kg de peso corporal diariamente durante 24 dias. O experimento teve duração de 60 dias e foi dividido em 5 momentos (M1= controle; M2=15 dias; M3= 30 dias; M4=45 dias e M5=60 dias), nos quais os animais foram submetidos a biópsias hepáticas e colheita de sangue para exames bioquímicos. As biópsias hepáticas foram processadas para MO, Imuno-histoquímica e MET. Como foram observados sinais clínicos digestivos no início da 3a semana suspendeu-se a administração da planta aos 24 dias. Mesmo assim as lesões foram progressivas, com morte de um animal aos 45 dias. A partir de M2 havia alterações degenerativas, necrose, apoptose e megalocitose de hepatócitos associadas à fibrose portal, centrolobular e pericelular. Foi feita morfometria por análise de imagem para colágeno total com...
Extracellular matrix (ECM) has been studied on chronic hepatic lesions of experimental intoxication models due to its relevant role in this pathologic process. Nevertheless there are no specific studies on ECM in normal or chronically damaged bovine liver. Hepatocellular damage has been more important center of attention in chronic bovine liver damage and ECM has been simply described. Because of this fact we decided to present a bovine model starting with detailed study of normal (control) liver biopsy taken from animals before experimental intoxication by Senecio brasiliensis. This plant contains pyrrolizidine alkaloids (PA) that causes acute or chronic progressive liver damage. The main objetive of this project is to do quantitative and / or semi-quantitative measurement of specific components of normal liver ECM and its change during progressive liver damage when bovines are submitted to chronic PA intoxication. Five animals received 0,38g of dry leaf of S. brasiliensis per Kg of body weight orally per day during 24 days. All but one animal were evaluated up to 60 th day. Liver biopsy and blood samples were collected on 5 moments (M1= controle; M = 15th day; M3 = 30th day; M4=45th day and M5=60th day). Biopsy samples were processed for light microscopy, immuno-histochemistry and transmission electron microscopy (TEM) at the begining of the 3rd week some clinical signs indicated digestive complications and we stoped giving toxic plant on 24th day of experiment. Liver lesions were progressive even after that day and one animal died on 45th day. From M2 on ligth microscopy showed hepatocellular degenerative changes, necrosis, apoptosis and megalocitosis plus portal, centrilobular and pericellular fibrosis. Morphometric study by analysis of image for total collagen was done using Picrossirius staining and for elastic fiber system was done using... (Complete abstract, click electronic address below)
Extracellular matrix (ECM) has been studied on chronic hepatic lesions of experimental intoxication models due to its relevant role in this pathologic process. Nevertheless there are no specific studies on ECM in normal or chronically damaged bovine liver. Hepatocellular damage has been more important center of attention in chronic bovine liver damage and ECM has been simply described. Because of this fact we decided to present a bovine model starting with detailed study of normal (control) liver biopsy taken from animals before experimental intoxication by Senecio brasiliensis. This plant contains pyrrolizidine alkaloids (PA) that causes acute or chronic progressive liver damage. The main objetive of this project is to do quantitative and / or semi-quantitative measurement of specific components of normal liver ECM and its change during progressive liver damage when bovines are submitted to chronic PA intoxication. Five animals received 0,38g of dry leaf of S. brasiliensis per Kg of body weight orally per day during 24 days. All but one animal were evaluated up to 60 th day. Liver biopsy and blood samples were collected on 5 moments (M1= controle; M = 15th day; M3 = 30th day; M4=45th day and M5=60th day). Biopsy samples were processed for light microscopy, immuno-histochemistry and transmission electron microscopy (TEM) at the begining of the 3rd week some clinical signs indicated digestive complications and we stoped giving toxic plant on 24th day of experiment. Liver lesions were progressive even after that day and one animal died on 45th day. From M2 on ligth microscopy showed hepatocellular degenerative changes, necrosis, apoptosis and megalocitosis plus portal, centrilobular and pericellular fibrosis. Morphometric study by analysis of image for total collagen was done using Picrossirius staining and for elastic fiber system was done using... (Complete abstract, click electronic address below)
Descrição
Palavras-chave
Senecio - Toxicologia - Estudos experimentais
Como citar
TORRES, Márcia Bersane Araújo de Medeiros. Lesões hepáticas de bovinos intoxicados experimentalmente por Senecio brasiliensis (Compositae): estudo semi-quantitativo e quantitativo da matriz extracelular e de células sinusoidais. 2003. 73 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2003.