Chronic Toxoplasma gondii infection and sleep‐wake alterations in mice

Abstract

Aim Toxoplasma gondii (Tg) is an intracellular parasite infecting more than a third of the human population. Yet, the impact of Tg infection on sleep, a highly sensitive index of brain functions, remains unknown. We designed an experimental mouse model of chronic Tg infection to assess the effects on sleep‐wake states. Methods Mice were infected using cysts of the type II Prugniaud strain. We performed chronic sleep‐wake recordings and monitoring as well as EEG power spectral density analysis in order to assess the quantitative and qualitative changes of sleep‐wake states. Pharmacological approach was combined to evaluate the direct impact of the infection and inflammation caused by Tg. Results Infected mouse exhibited chronic sleep‐wake alterations over months, characterized by a marked increase (>20%) in time spent awake and in cortical EEG θ power density of all sleep‐wake states. Meanwhile, slow‐wave sleep decreased significantly. These effects were alleviated by an anti‐inflammatory treatment using corticosteroid dexamethasone. Conclusion We demonstrated for the first time the direct consequences of Tg infection on sleep‐wake states. The persistently increased wakefulness and reduced sleep fit with the parasite's strategy to enhance dissemination through host predation and are of significance in understanding the neurodegenerative and neuropsychiatric disorders reported in infected patients.

Toxoplasma gondii infection and insomnia: A case control seroprevalence study

“…In an experimental mouse model of chronic T . gondii infection, investigators found that infected mice exhibited chronic sleep–wake alterations over months, including a marked increase in time spent awake [ 25 ]. Further research to determine the association between insomnia and T .…”

Crosstalk between circadian clocks and pathogen niche

“…It is worth considering the role of circadian rhythms on other neurotrophic pathogens, many of which can establish chronic infection and alter sleep rhythms, as demonstrated for Toxoplasma gondii [ 136 ]. Interestingly, crosstalk between the brain and daily changes in gut microbiota was shown to contribute to aging-associated neurodegenerative diseases [ 137 ].…”