Effects of Toxocara larvae on brain cell survival by in vitro model assessment

Abstract

Neuroinvasive larvae of the common dog and cat roundworms, Toxocara canis and Toxocara cati, may cause severe neurological and neuropsychological disturbances in humans. Despite their pathogenic potential and high prevalence worldwide, little is known about their cell-specific influences and cerebral host-pathogen interactions in neurotoxocarosis. To address this discrepancy, a co-culture system of viable larvae with murine neuronal (CAD), oligodendrocytal (BO-1) and microglial (BV-2) cell lines has been established. Additionally, murine adult brain slices have been co-cultured with Toxocara larvae to consider complex organotypic cell-cell interplay. Cytotoxicity of larval presence was measured enzymatically and microscopically. Microscopic evaluation using trypan blue exclusion assay revealed to be less reliable and sensitive than the lactate dehydrogenase activity assay. Ultimately, even low numbers of both T. canis and T. cati larvae have impaired survival of differentiated CAD cells, which morphologically resemble primary neurons. In contrast, viability of oligodendrocytal and microglial cells as well as brain slices was not impaired by larval presence. Therefore, immune-mediated mechanisms or trauma by migrating larvae presumably induce the in vivo pathology rather than acute cytotoxic effects. Conclusively, the helminthic larvae co-culture system presented here is a valuable in vitro tool to study cell-specific effects of parasitic larvae and their products.

Abnormal neurobehaviour and impaired memory function as a consequence of Toxocara canis- as well as Toxocara cati-induced neurotoxocarosis

“…canis -infection, with concurrent delayed onset in T . cati -infection in terms of clinical symptoms as well as transcriptional and histopathological alterations in the brain [22,24,35,36]. In contrast to the presented study, previously conducted behavioural studies showed no differences in general health of T .…”

Zoonotic intestinal helminths interact with the canine immune system by modulating T cell responses and preventing dendritic cell maturation

“…T. canis eggs were washed and embryonated in tap water at 25 °C for about 4 weeks. Larval hatching was carried out in vitro as described elsewhere 70 . For A. caninum , obtained eggs were incubated in a coproculture for about one week until development of L3.…”

A Hydroalcoholic Extract from Paullinia pinnata L. Roots Exerts Anthelmintic Activity against Free-Living and Parasitic Nematodes

“…Worms were scored as dead if their body was completely straight and they did not react when probed with an eyelash. Toxocara catimortality assay: L3 stage larvae for the in vitro assay were prepared as described recently in detail by Heuer et al [52]. A stock solution (5 mg/mL) of the extract was prepared and aliquots were diluted in test medium in a 48-well plate to a final volume of 500 µL per well.…”