Thesis

Relationship between Toxoplasma gondii infection and psychiatric disorders

Creator
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Awarding institution
  • University of Strathclyde
Date of award
  • 2009
Thesis identifier
  • T12343
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • Toxoplasma gondii has been suggested to be a risk factor for the development of schizophrenia, depression and has been associated with behavioural changes in humans and rodents. As T. gondii fonns cysts that are located mainly in the brain during a chronic infection, it is well placed anatomically to mediate these effects. Recently, changes in the immune response have also been associated with mood and behavioural alterations and compounds designed to alter mood, such as fluoxetine, have been demonstrated to alter aspects of immune function. Herein, the ability of T.gondii to alter murine behaviour is assessed through a series of behavioural tests. The hypothesis that T. gondii induced IFNy, through the production of Indolamine 2,3,Dioxygenase (lDO), can result in degradation of tryptophan leading to the inhibition of serotonin is investigated. To this end, groups of animals infected with T. gondii were sacrificed and mRNA transcripts for Indolamine 2-3 Dioxygenase (lDO),Tryptophan hydroxylase (TPH2) and tryptophan oxygenase (TD02) that are involved in the tryptophan degradation pathways were assessed and quantified, together with IFN-y by Real time PCR (qRT-PCR). Assessment of mouse behaviour in the open field test demonstrates that T. gondii infection increases time spent in the centre of the field compared with unifected controls, potentially indicating decreased anxiety. In mice infected with T. gondii. for 1 month had decreased prepulse inhibition reactions compared with control animals. This indicates a deficit in sensorigating as observed in humans with schizophrenia. Transcripts for IFN-y were detected in the brains of infected, but not control mice. In spite of this no difference in the levels of IDO, TDO or TPH2 transcripts were detected in the brains of control and infected mice.
Resource Type
DOI
Date Created
  • 2009
Former identifier
  • 997971743402996

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