PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

Crotalaria spectabilis seed poisoning has been reported in cattle on rural properties in Diamantino and Campo Verde municipalities in Mato Grosso, Brazil. The disease appeared 75 to 120 days after the animals were fed a diet contaminated with C. spectabilis seeds. Clinically, the animals showed a lack of appetite, progressive weight loss, apathy, photosensitivity, lateral recumbency, and death. Some animals developed neurological manifestations as a consequence of hepatic encephalopathy. In total, 37 cattle died, and six cattle were necropsied. The main macroscopic changes consisted of ascites and a firm and decreased liver with an irregular surface and multifocal pale yellowish discoloration. Microscopically, hepatocyte loss with fibrosis, megalocytosis and bile duct proliferation was observed. Animals with severe hepatic damage also had status spongiosus in the central nervous system. Furthermore, a hepatic biopsy of 15 cows who consumed contaminated grains but did not develop clinical disease revealed histologic liver changes similar to necropsied animals.

• Crotalaria spectabilis hepatic fibrosis pyrrolizidine alkaloids monocrotaline cattle

Abstract in Portuguese:

Relata-se dois surtos de intoxicação por sementes de Crotalaria spectabilis em bovinos em propriedades rurais nos municípios de Diamantino e Campo Verde, Mato Grosso, Brasil. A doença apareceu 75 a 120 dias depois que os animais foram alimentados com uma dieta contaminada com sementes de C. spectabilis. Clinicamente, foi observado falta de apetite, perda de peso progressiva, apatia, fotossensibilização, decúbito lateral e morte. Alguns animais desenvolveram manifestações neurológicas secundárias à encefalopatia hepática. No total, 37 bovinos morreram e seis deles foram submetidos à necropsia. As principais alterações macroscópicas consistiram em ascite e fígado diminuído em tamanho com superfície capsular irregular, difusamente firme e com áreas multifocais amarelo-pálidas. Microscopicamente, foi observado perda de hepatócitos acompanhada de fibrose hepática com megalocitose e proliferação de ductos biliares. No sistema nervoso central de bovinos com lesões hepáticas graves havia status spongiosus. A biópsia hepática de 15 bovinos que consumiram grãos contaminados, mas estavam clinicamente sadios, revelou alterações hepáticas similares às descritas nos animais submetidos à eutanásia.

• Crotalária fibrose hepática alcaloides pirrolizidínicos monocrotalina bovinos

Abstract in English:

ABSTRACT.- Torres M.B.A.M. & Coelho K.I.R. 2008. Experimental poisoning by Senecio brasiliensis in calves: quantitative and semi-quantitative study on changes in the hepatic extracellular matrix and sinusoidal cells. Pesquisa Veterinária Brasileira 28(1):43-50. Laboratório de Patologia Veterinária, Universidade Federal do Paraná, Campus Palotina, Rua Pioneiro 2153, Jardim Dallas, Palotina, PR 85950-000, Brazil. E-mail: torres@ufpr.br Extracellular matrix plays an important role in chronic hepatic lesions and has been studied in experimental intoxication models. However in cattle, studies on chronic disease have focused on the hepatocellular damage and extracellular matrix (ECM) changes are usually overlooked. There are no specific studies on the hepatic ECM in either normal or chronically damaged bovine liver. Thus an experimental model of hepatic toxicity model using Senecio brasiliensis poisoned calves was designed. Senecio brasiliensis contains pyrrolizidine alkaloids which cause either acute or chronic progressive dose dependent liver damage. Five calves were orally fed with 0.38g of dry leaves of S. brasiliensis/kg/day for 24 days. Liver needle biopsy specimens were obtained every 15 days for 60 days. Clinical signs of digestive complications appeared at 3rd week. One calf died on 45th day and four were evaluated up to 60th day. Biopsy samples were processed for routine light microscopy, immuno-histochemistry and transmission electron microscopy. From 30th day on progressive liver damage characterized by hepatocellular ballooning, necrosis, apoptosis and megalocytosis, centrilobular, pericellular and portal fibrosis were seen by light microscopy. Quantitative and semi-quantitative measurements of hepatic ECM components were performed before and after the onset of lesions. Morphometric analysis of total collagen and elastic fiber system was conducted. Total collagen and I and III collagen types progressively increased in throughout the liver of affected calves. Changes in location, amount and disposition of the elastic fiber system were also observed. Then numbers of Kupffer cells were significantly increased at 30th day and total numbers of sinusoidal cells were significantly increased at 45th and 60th days. Liver damage was progressive and irreversible even after the exposure to the plant was discontinued. Severe fibrotic lesions occurred mainly in portal tracts, followed by veno-occlusive and pericellular fibrosis. Collagen types I and III s were present in every normal and damaged liver, with predominance of type I. In affected calves the increase of total collagen and elastic fibers system paralleled the number of total sinusoidal cells.

• Hepatic extracellular matrix sinusoidal cells hepatic fibrosis pyrrolizidine alkaloids

Abstract in Portuguese:

ABSTRACT.- Torres M.B.A.M. & Coelho K.I.R. 2008. Experimental poisoning by Senecio brasiliensis in calves: quantitative and semi-quantitative study on changes in the hepatic extracellular matrix and sinusoidal cells. Pesquisa Veterinária Brasileira 28(1):43-50. Laboratório de Patologia Veterinária, Universidade Federal do Paraná, Campus Palotina, Rua Pioneiro 2153, Jardim Dallas, Palotina, PR 85950-000, Brazil. E-mail: torres@ufpr.br Extracellular matrix plays an important role in chronic hepatic lesions and has been studied in experimental intoxication models. However in cattle, studies on chronic disease have focused on the hepatocellular damage and extracellular matrix (ECM) changes are usually overlooked. There are no specific studies on the hepatic ECM in either normal or chronically damaged bovine liver. Thus an experimental model of hepatic toxicity model using Senecio brasiliensis poisoned calves was designed. Senecio brasiliensis contains pyrrolizidine alkaloids which cause either acute or chronic progressive dose dependent liver damage. Five calves were orally fed with 0.38g of dry leaves of S. brasiliensis/kg/day for 24 days. Liver needle biopsy specimens were obtained every 15 days for 60 days. Clinical signs of digestive complications appeared at 3rd week. One calf died on 45th day and four were evaluated up to 60th day. Biopsy samples were processed for routine light microscopy, immuno-histochemistry and transmission electron microscopy. From 30th day on progressive liver damage characterized by hepatocellular ballooning, necrosis, apoptosis and megalocytosis, centrilobular, pericellular and portal fibrosis were seen by light microscopy. Quantitative and semi-quantitative measurements of hepatic ECM components were performed before and after the onset of lesions. Morphometric analysis of total collagen and elastic fiber system was conducted. Total collagen and I and III collagen types progressively increased in throughout the liver of affected calves. Changes in location, amount and disposition of the elastic fiber system were also observed. Then numbers of Kupffer cells were significantly increased at 30th day and total numbers of sinusoidal cells were significantly increased at 45th and 60th days. Liver damage was progressive and irreversible even after the exposure to the plant was discontinued. Severe fibrotic lesions occurred mainly in portal tracts, followed by veno-occlusive and pericellular fibrosis. Collagen types I and III s were present in every normal and damaged liver, with predominance of type I. In affected calves the increase of total collagen and elastic fibers system paralleled the number of total sinusoidal cells.