Avaliação eletrofisiológica e histopatológica do músculo estriado esquelético em cães naturalmente acometidos pela leishmaniose visceral
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Data
2008-08-04
Autores
Ferraro, Gisela Cristiane [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A leishmaniose visceral canina é uma enfermidade geralmente crônica que pode causar hipertermia, perda progressiva de peso, caquexia e atrofia muscular. Existem na literatura relatos da observação de formas amastigotas do parasita na musculatura estriada esquelética de cães, entretanto a patogenia da miopatia permanece incerta. Dessa forma, o objetivo desse estudo foi avaliar as alterações eletromiográficas e histopatológicas em músculos estriados esqueléticos de cães naturalmente acometidos por leishmaniose visceral. Para tanto, 25 cães adultos, machos ou fêmeas, sem raça definida e com diagnóstico parasitológico e sorológico estabelecido para a doença foram utilizados. Os músculos selecionados foram: cabeça longa do tríceps braquial, extensor carpo radial, bíceps femoral e cabeça lateral do gastrocnêmio. Entre os achados eletromiográficos estão o aumento (24% dos cães) e diminuição (68%) da atividade elétrica insersional; presença de potenciais espontâneos (52%) durante a atividade elétrica de repouso, caracterizados por ondas positivas, fibrilações e descargas complexas repetitivas; e recrutamento alterado (72%) na atividade elétrica voluntária. O exame histopatológico revelou variados graus de degeneração e necrose (80%); presença de infiltrado inflamatório mononuclear (48%); presença de fibrose (56%); variação no diâmetro das miofibras (60%); e presença de células adiposas no endomísio (40%). Estas alterações são consistentes com um quadro de polimiosite em fase crônica para 52% dos animais, em fase aguda para 8% e em fase indefinida em 16%.
Canine visceral leishmaniasis is a cronic disease that can cause fever, progressive weight loss, cachexia and muscle atrophy. There are few reports in literature that describe the observation of amastigote forms of the parasite in muscles, however, the pathogenesis of the miopathy remains unclear. The aim of the present study was evaluate the electromyographic and histopathologic changes in skeletal muscle of dogs naturally infected by visceral leishmaniasis. For this, twenty-five dogs adult mongrels of both sexes with a parasitologically and serologically established diagnosis of leishmaniasis were used. The muscles selected were: triceps brachial, extensor carpi radialis, biceps femoris and gastrocnemius. The electromyograph abnormalities included decreased (68% of dogs) and increased (24%) insertion activity; abnormal spontaneous activity (52%) in the form of positive sharp waves, fibrilation potentials and bizarre high frequency discharges and abnormal recruitment of motor unit action potential (72%) during voluntary activity. Histological examination showed various degrees of degeneration and myonecrosis (80%), perimysial and endomysial lymphocytes infiltrations (48%), variation in myofibers sizes (60%), and replacement of muscle fibres by fibrous tissue (56%) and adipose tissue (40%). These changes were considered to be consistent with a chronic phase of polymyositis in 52% of the dogs, in acute phase for 8% and variable phase for 16% of the dogs.
Canine visceral leishmaniasis is a cronic disease that can cause fever, progressive weight loss, cachexia and muscle atrophy. There are few reports in literature that describe the observation of amastigote forms of the parasite in muscles, however, the pathogenesis of the miopathy remains unclear. The aim of the present study was evaluate the electromyographic and histopathologic changes in skeletal muscle of dogs naturally infected by visceral leishmaniasis. For this, twenty-five dogs adult mongrels of both sexes with a parasitologically and serologically established diagnosis of leishmaniasis were used. The muscles selected were: triceps brachial, extensor carpi radialis, biceps femoris and gastrocnemius. The electromyograph abnormalities included decreased (68% of dogs) and increased (24%) insertion activity; abnormal spontaneous activity (52%) in the form of positive sharp waves, fibrilation potentials and bizarre high frequency discharges and abnormal recruitment of motor unit action potential (72%) during voluntary activity. Histological examination showed various degrees of degeneration and myonecrosis (80%), perimysial and endomysial lymphocytes infiltrations (48%), variation in myofibers sizes (60%), and replacement of muscle fibres by fibrous tissue (56%) and adipose tissue (40%). These changes were considered to be consistent with a chronic phase of polymyositis in 52% of the dogs, in acute phase for 8% and variable phase for 16% of the dogs.
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Palavras-chave
Cão - Histopatologia, Leishmania, Eletromiografia, Miopatia, Polimiosite, Electromyographic, Myopathy, Polymyositis
Como citar
FERRARO, Gisela Cristiane. Avaliação eletrofisiológica e histopatológica do músculo estriado esquelético em cães naturalmente acometidos pela leishmaniose visceral. 2008. xv, 90 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinária, 2008.