Behavioural alterations are independent of sickness behaviour in chronic experimental Chagas disease.

Glaucia Vilar-Pereira,Joseli Lannes-Vieira,Leonardo Alexandre De Souza Ruivo

doi:10.1590/0074-02760150300

Glaucia Vilar-Pereira, Joseli Lannes-Vieira + Show 1 more

Open Access

https://doi.org/10.1590/0074-02760150300

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Abstract

The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals. In most patients, the clinical manifestations of the acute phase, including neurological abnormalities, resolve spontaneously without apparent consequence in the chronic phase of infection. However, chronic Chagas disease patients have behavioural changes such as psychomotor alterations, attention and memory deficits, and depression. In the present study, we tested whether or not behavioural alterations are reproducible in experimental models. We show that C57BL/6 mice chronically infected with the Colombian strain of T. cruzi (150 days post-infection) exhibit behavioural changes as (i) depression in the tail suspension and forced swim tests, (ii) anxiety analysed by elevated plus maze and open field test sand and (iii) motor coordination in the rotarod test. These alterations are neither associated with neuromuscular disorders assessed by the grip strength test nor with sickness behaviour analysed by temperature variation sand weight loss. Therefore, chronically T. cruzi-infected mice replicate behavioural alterations (depression and anxiety) detected in Chagas disease patients opening an opportunity to study the interconnection and the physiopathology of these two biological processes in an infectious scenario.

Highlights

The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals
In the present study we challenged the hypothesis that the behavioural abnormalities depression and anxiety described in Chagas disease patients are nonpsychological features and could be reproduced in a model of experimental T. cruzi infection
We tested whether infection with a T. cruzi Type I strain that allows survival and development of the chronic phase of infection led to the behavioural alterations depression, anxiety, and locomotor/exploratory disorders

Summary

Introduction

The existence of the nervous form of Chagas disease is a matter of discussion since Carlos Chagas described neurological disorders, learning and behavioural alterations in Trypanosoma cruzi-infected individuals. We show that C57BL/6 mice chronically infected with the Colombian strain of T. cruzi (150 days post-infection) exhibit behavioural changes as (i) depression in the tail suspension and forced swim tests, (ii) anxiety analysed by elevated plus maze and open field test sand and (iii) motor coordination in the rotarod test These alterations are neither associated with neuromuscular disorders assessed by the grip strength test nor with sickness behaviour analysed by temperature variation sand weight loss. We have shown that depressive-like behaviour in the chronic phase of experimental T. cruzi infection in mice models is independent of the prior existence of acute meningoencephalitis, and, is not a sequel of this (Vilar-Pereira et al 2012) It has not been explored whether or not anxiety is present in the chronic phase of experimental Chagas disease in association with depressive behaviour. We assessed whether there is or not a relation between depression and anxiety with loss of muscle strength and/or sickness behaviour in the chronic phase of experimental Chagas disease

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