Resumo

Leukoencephalomyelopathy is a nonspecific lesion characterized by widespread vacuolation of central nervous system white matter. It is mainly of genetic basis, occurring in young pure breed dogs. This report describes a neurodegenerative disease associated to demyelination in an adult mixed breed female dog. After 20 days in a kennel with12 other dogs, the dog showed progressive nervous signs with ataxia and inability to maintain balance. No other dog was affected. After 15 days, the animal was euthanized in extremis and necropsied. No macroscopic lesions of diagnostic relevance were present. Microscopically, status espongiosus was observed in white matter throughout the length of theneuroaxis, from frontal brain lobe to lumbar spinal cord. Specific stains of Kluver Barrera and immunohistochemistry for the detection of phosphorylated and non-phosphorylated neurofilaments, microglia, astrocytosis, oligodendrocytosis and myelin proteins in brain and spinal cord sections showed demyelination, axonal fragmentation and degeneration, microgliosis and decrease of oligodendrocytes. The anatomopathological study and epidemiological data suggests a primary demyelination due to decrease in number and function of oligodendrocytes, which is probably of genetic basis with lateonset.

Resumo

Fifteen mature crossbred sheep were fed different daily amounts (2.5-35g kg-1 bw) of the fresh green leaves of Ateleia glazioviana for different periods of time (1-24 days). One sheep was not fed the plant and served as a control. All 16 sheep were euthanatized at different stages of the experiment, necropsied, and several organs, including heart and brain were evaluated histologically. Samples of five brain regions from three affected sheep were evaluated by electron microscopy. Clinical signs observed in three sheep included depression, anorexia, general weakness, staggering gait and prolonged recumbency. One sheep had signs of congestive heart failure. Necropsy findings included subcutaneous dependent edema and edema of the body cavities in two sheep and nutmeg liver in one. Histopathological findings included degeneration, necrosis and interstitial fibrosis in the myocardium of four sheep and vacuolation of cerebral white matter (spongy degeneration, status spongiosus) in 10 sheep, although this latter change were marked only in two of those 10. The ultrastructure of the brain lesion was morphologically consistent with that found in diseases grouped as spongiform myelinopathies in which vacuolation of the myelin occurs in the absence of significant myelin breakdown or phagocytosis. The morphology and pathogenesis of the chronic cardiomyopathy and of the cerebral spongy degeneration in affected sheep in this experiment are discussed and compared with other similar conditions in domestic ruminants.

Quinze ovinos mestiços adultos receberam quantidades variáveis (2,5-35g kg-1 pv), por via oral, das folhas verdes frescas de Ateleia glazioviana durante períodos de tempo que variaram de 1 a 24 dias. Um ovino não recebeu a planta e serviu como controle. Todos os 16 ovinos foram submetidos à eutanásia em diferentes estágios do experimento, necropsiados, e vários órgãos, incluindo coração e encéfalo, foram avaliados histologicamente. Fragmentos de cinco regiões do encéfalo de três ovinos afetados foram avaliados por microscopia eletrônica. Sinais clínicos observados em três ovinos incluíam depressão, anorexia, fraqueza geral, andar vacilante e decúbito prolongado. Um ovino apresentou sinais de insuficiência cardíaca congestiva. Achados de necropsia incluíram edema subcutâneo de declive e das cavidades orgânicas em dois ovinos e fígado de noz-moscada em umdeles. Achados histopatológicos incluíram necrose e fibrose intersticial no miocárdio de quatro ovinos e vacuolização da substância branca (degeneração esponjosa, status spongiosus) em 10 ovinos, embora essa última alteração fosse acentuada em apenas dois ovinos. A ultra-estrutura das lesões encefálicas foi morfologicamente consistente com o que é descrito em um grupo de doenças conhecidas como mielinopatias espongiformes nas quais a vacuolização da mielina ocorre na ausência de degradação significativa da mielina ou fagocitose. A morfologia e patogênese da miocardiopatia crônica e da degeneração esponjosa encefálica nos ovinos deste experimento são discutidas e comparadas com outras condições semelhantes em animais domésticos.

Resumo

Este estudo foi realizado para investigar os seguintes aspectos da intoxicação por Ateleia glazioviana em ovinos: (1) as propriedades abortivas da planta e a patogênese dos abortos e da falha reprodutiva associada à toxicose e (2) a morfologia e patogênese das lesões cardíacas e encefálicas. Para a primeira parte do experimento, 17 ovelhas prenhes receberam, por via oral, diferentes quantidades das folhas verdes ou secas de A. glazioviana fracionadas em 1-24 doses diárias. Todas as 17 ovelhas manifestaram alguma forma de falha reprodutiva. Nove ovelhas (52,9%) abortaram seus fetos aos 4- 36 dias após o início da administração da planta; houve um natimorto e uma morte intra-uterina. Seis ovelhas pariram 8 cordeiros fracos, sete dos quais morreram de alguns minutos até 48 horas após o nascimento. Alterações macro e microscópicas observadas em cordeiros, num natimorto e nos fetos abortados eram notavelmente semelhantes às observadas na intoxicação espontânea por A. glazioviana em ruminantes. Foi concluído que os abortos causados por A. glazioviana são devidos às lesões induzidas no feto por via transplacentária e consistem de miocardiopatia tóxica e degeneração esponjosa da substância branca do encéfalo. Para a segunda parte do experimento, 15 ovinos adultos receberam diferentes quantidades diárias das folhas verdes frescas de A. glazioviana por vários períodos de tempo (1-24 dias). Os sinais clínicos observados nos ovinos afetados incluíram depressão, anorexia, fraqueza, incoordenação e decúbito prolongado. Um ovino apresentou sinais de insuficiência cardíaca congestiva. Os achados de necropsia incluíram edema subcutâneo e das cavidades orgânicas em dois ovinos e fígado de noz moscada em um. Os achados histopatológicos incluíram degeneração, necrose e fibrose intersticial no miocárdio em 4 ovinos e degeneração esponjosa da substância branca do encéfalo (status spongiosus) em 10 ovinos. A ultra-estrutura da lesão encefálica foi morfologicamente classificada no grupo das mielinopatias espongiformes em que ocorre vacuolização da mielina sem degradação ou fagocitose significativas

This experiment was undertaken to study the following aspects of the A. glazioviana poisoning in sheep: (1) abortifacient properties of the plant and the pathogenesis of the abortions and reproductive failure associated with the toxicosis and (2) the morphology and pathogenesis of cardiac and brain lesions. In the first part of the experiment, 17 pregnant ewes were orally fed variable amounts of either green or dried leaves of A. glazioviana fractioned in 1-24 daily doses. All 17 ewes manifested some form of reproductive failure. Nine (52.9%) aborted their fetuses at 4-36 days after starting being fed the leaves of the plant; one had a stillbirth and in another one intrauterine fetal death was diagnosed. The other six ewes delivered 8 weak lambs seven of which died from few minutes to 48 hours after birth. Gross and histopathological changes observed in lambs, stillborn, and in aborted fetuses were rather similar to those found in the spontaneous poisoning by A. glazioviana in ruminants. It is concluded that abortions caused by A. glazioviana are due to transplacental induced fetal lesions consisting of toxic cardiomyopathy and spongy degeneration of the white matter of the brain. For the second part of the experiment 15 mature sheep were fed varying daily amounts of the fresh green leaves of A. glazioviana for different periods of time (1-24 days). Clinical signs observed in poisoned sheep included depression, anorexia, general weakness, staggering gait and prolonged recumbency. One sheep had signs of congestive heart failure. Necropsy findings included subcutaneous and cavitary edema in two sheep and nutmeg liver in one. Histopathological findings included degeneration, necrosis and interstitial fibrosis in the myocardium of 4 sheep and spongy degeneration of cerebral white matter (status spongiosus) in 10 sheep. The ultrastructure of the brain lesion was morphological consistent with those found in diseases grouped as spongiform myelinopathies in which vacuolation of myelin occur in absence of significant myelin break down or phagocytosis