β-glucan alleviates goal-directed behavior in mice infected with Toxoplasma gondii

Abstract

Abstract Background Toxoplasma gondii (T. gondii) is a neuroinvasive parasite causing neuroinflammation, which is associated with a higher risk for several psycho-behavioral disorders. There is an urgent need to identify drugs capable of improving cognitive deficits induced by T. gondii infection. (1, 3)/(1, 6)-β-glucan, an active ingredient in mushrooms, could significantly enhance immunity. However, the effects of β-glucan against neuroinflammation and cognitive decline induced by T. gondiiinfection remain unknown. The present study aimed to investigate the neuroprotective effect of β-glucan on goal-directed behavior of mice chronically infected by T. gondii Wh6 strain. Methods A mice model of chronic T. gondii Wh6 infection was established by gavage of 10 cysts. Intraperitoneal injection of β-glucan was manipulated two weeks before T. gondiiinfection. Y-maze test and temporal order memory (TOM) test were performed to assess the goal-directed behavior. Golgi-Cox staining, transmission electron microscopy, immunofluorescence, Real-Time PCR and western blot assays were used to detect prefrontal cortex-associated pathological change and neuroinflammation. Results We reported that administration of β-glucan significantly prevented T. gondii Wh6-induced goal-directed behavioral impairment assessed behaviorally by Y-maze test and TOM test. In the prefrontal cortex, β-glucan could counter T. gondii Wh6 -induced degeneration of neurites, impairment of synaptic ultrastructure, and decrease of pre- and postsynaptic protein levels. Also, β-glucan significantly prevented the hyperactivation of pro-inflammatory microglia and astrocytes, as well as the upregulation of proinflammatory cytokines caused by chronic T. gondii Wh6 infection. Conclusion This study revealed that β-glucan prevents goal-directed behavioral impairment induced by chronic T. gondii infection in mice. These findings suggested that β-glucan may be an effective drug candidate to prevent T. gondii-associated psycho-behavioral disorders including goal-directed behavioral injury.