Chronic Toxoplasma gondii infection induces behavioural and cognitive changes: a model of study

FLORENCIA ANDRÉS, NADIA ARCON, MATÍAS PERRONE SIBILIA, ROSALÍA MORETTA, ALEJANDRA GOLDMAN, VALENTINA MARTIN, VANESA SÁNCHEZ

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2019

Recently, lot of evidence has been accumulated that links T. gondii chronic infection with different pathologies including neurocognitive and behavioural conditions among others. There are no treatments able to eliminate the parasite at this stage or to reduce the adverse effects associated with the infection. Herein, we aimed to set out different tests to study the effect of chronic infection on neurocognitive and behavioural abilities.According to the literature, it is necessary to use at least two tests to evaluate the different abilities, so we selected the Open Field (OF), Hole Board (HB) and Forced Swim (FS) tests. Chronically infected and naive C57BL/6 mice were used. Infection was confirmed before the tests by serology, and brain cyst count at the end. The OFT lets the study of behavioural changes. The exploratory ability in infected mice was reduced compared to the control group (33,7% less line crosses, less time spent in the centre of arena and reduction in two leg stand (85,5 %)). We confirmed this result with the HBT, where infected mice showed 62,8% less nose-poked. To evaluate learning/memory abilities, nose-poked habituation task trials were done. When the test was carried out 24 h after training, the reduction in the exploratory activity was remarkably lower in infected mice (15,6% in infected vs 69,7 % in Control group). Also, in FST infected mice showed shorter flotation times than controls (46,6 %). To study memory abilities, flotation time after training was analysed. While in controls this parameter was 36,8% increased, infected mice showed no variation. Altogether, these data showed alterations to face new or previously experienced situations in chronically infected mice. Finally, the devices we have set out and the tests used in this work allow us to study the effects of chronic toxoplasmosis at a cognitive and behavioural level. Moreover, they can be used to study therapies aimed at improving the neurological effects in chronically infected mice.