Resumo A neurocisticercose (NCC) é classificada como uma doença tropical negligenciada que afeta principalmente a América Latina e a África, apesar de alguns relatos na América do Norte e na Europa. A NCC é responsável por cerca de 30% dos casos de epilepsia em países endêmicos. Estas lesões parecem ter estreita relação com o estádio de desenvolvimento, com a localização e o número de parasitas, bem como a resposta imune do hospedeiro. O presente estudo objetivou caracterizar a resposta de células inflamatórias e as lesões teciduais pela análise da desmielinização periventricular e parenquimatosa ao longo da infecção experimental de NCC intraventricular. Para tanto, camundongos BALB/c foram submetidos a NCC experimental através da inoculação de cisticercos de Taenia crassiceps. O encéfalo foi retirado aos 7, 30, 60 e 90 dias após inoculação (DAI) e analisado após coloração por Hematoxilina e Eosina (HE), Luxol Fast Blue e Nissl. Observou-se ventriculomegalia, processo de infiltração inflamatório composto por células polimorfonucleares, mononucleares e macrófagos espumosos. A presença de células inflamatórias foi associada com neurodegeneração, observada pelas áreas de desmielinização que foram inicialmente periventricular e mais tardiamente no parênquima. Em conclusão, observa-se que a presença dos cisticercos e a inflamação foram capazes de promover desmielinização periventricular inicial e parenquimatosa conforme houve progressão tardia da infecção.

Abstract Neurocysticercosis (NCC) is classified as a neglected tropical disease, which affects mainly Latin America and Africa in spite of some reports in North America and Europe. NCC represents the cause of up to 30% of the reported cases of epilepsy in endemic countries. The NCC injuries present direct relation to the development stage, location, and number of parasites as well as to the host immune response. This study aimed the characterization of the inflammatory response and tissue injuries by means of the analyses of the periventricular and parenchymatous demyelination through the experimental intraventricular NCC infection. Therefore, BALB/c mice were submitted to experimental NCC inoculation with Taenia crassiceps cysticerci. Their brains were removed at 7, 30, 60, and 90 days after the inoculation (DAI), and analyzed after staining with hematoxylin and eosin (HE), Luxol Fast Blue, and Nissl. It was possible to observe ventriculomegaly, inflammatory infiltration composed by polymorphonuclear and mononuclear cells, and foamy macrophages. The presence of inflammatory cells was associated with neurodegeneration detected by the areas with demyelination observed initially in the periventricular area and lately in the parenchyma. In conclusion, the presence of cysticerci and the consequent inflammation were able to promote initial periventricular demyelination followed by parenchymatous demyelination as the infection progressed.

SUMMARY Human cysticercosis is one of the most severe parasitic infections affecting tissues. Experimental models are needed to understand the host-parasite dynamics involved throughout the course of the infection. The subcutaneous experimental model is the closest to what is observed in human cysticercosis that does not affect the central nervous system. The aim of this study was to evaluate macroscopically and microscopically the experimental subcutaneous cysticercosis caused by Taenia crassiceps cysticerci in BALB/c and C57BL/6 mice. Animals were inoculated in the dorsal subcutaneous region and macroscopic and microscopic aspects of the inflammatory process in the host-parasite interface were evaluated until 90 days after the inoculation (DAI). All the infected animals presented vesicles containing cysticerci in the inoculation site, which was translucent at 7 DAI and then remained opaque throughout the experimental days. The microscopic analysis showed granulation tissue in BALB/c mice since the acute phase of infection evolving to chronicity without cure, presenting 80% of larval stage cysticerci at 90 DAI. While C57BL/6 mice presented 67% of final stage cysticerci at 90 DAI, the parasites were surrounded by neutrophils evolving to the infection control. It is possible to conclude that the genetic features of susceptibility (BALB/c) or resistance (C57BL/6) were confirmed in an experimental subcutaneous model of cysticercosis.