Detecção imuno-histoquímica e molecular de Leishmania na medula espinhal de cães naturalmente infectados

Abstract

The mandatory intracellular protozoan Leishmania infantum can have a wide distribution in dog tissues, which can result in atypical clinical manifestations, such as neurological disorders, resulting from the involvement of the Central Nervous System (CNS). These manifestations are usually the result of an exacerbated inflammatory response to infection, which determines the deposition of immune complexes in these organs, suggesting that these signs are the result of an imbalance in the host's immune response. There are few studies in the literature that demonstrate the involvement of the CNS in dogs with visceral leishmaniasis, therefore, we sought to characterize the tissue immunopathological changes that occurred in the spinal cord of dogs with naturally infected CVL, determining and characterizing the possible histopathological changes, emphasizing the possible histopathological changes. immunohistochemical, histopathological and molecular. For this purpose, fragments of the spinal cord corresponding to the cervical, thoracic and lumbar portions of 20 dogs of both sexes, naturally infected with L. infantum, were collected and submitted to the techniques of histology, immunohistochemistry and qPCR. Macroscopically, no spinal cord injuries were observed in any of the animals evaluated in this study. Histopathological analysis showed alterations in spinal cord tissues of 13 animals, with the lesions observed being characterized as discrete and multifocal and, most of them, of a degenerative nature, characterized as central chromatolysis, satellitosis and vacuolization of the neuropile (Wallerian degeneration). In immunohistochemistry, it was possible to detect antigens from Leishmania sp. in the spinal cord of 5 dogs and, using qPCR, the parasite's DNA was detected in at least two portions (cervical, thoracic and / or lumbar) of the spinal cord of all animals analyzed. This study demonstrates that the spinal cord of dogs can be affected during Leishmania infection and that microscopic lesions are common in all portions of the spinal cord, with no significant predilection for any of the regions of this organ