BACKGROUND Behavioral and neurochemical alterations associated with toxoplasmosis may be influenced by the persistence of tissue cysts and activation of an immune response in the brain of Toxoplasma gondii-infected hosts. The cerebral extracellular matrix is organised as perineuronal nets (PNNs) that are both released and ensheath by some neurons and glial cells. There is evidences to suggest that PNNs impairment is a pathophysiological mechanism associated with neuropsychiatric conditions. However, there is a lack of information regarding the impact of parasitic infections on the PNNs integrity and how this could affect the host’s behavior. OBJECTIVES In this context, we aimed to analyse the impact of T. gondii infection on cyst burden, PNNs integrity, and possible effects in the locomotor activity of chronically infected mice. METHODS We infected mice with T. gondii ME-49 strain. After thirty days, we assessed locomotor performance of animals using the open field test, followed by evaluation of cysts burden and PNNs integrity in four brain regions (primary and secondary motor cortices, prefrontal and somesthetic cortex) to assess the PNNs integrity using Wisteria floribunda agglutinin (WFA) labeling by immunohistochemical analyses. FINDINGS AND MAIN CONCLUSIONS Our findings revealed a random distribution of cysts in the brain, the disruption of PNNs surrounding neurons in four areas of the cerebral cortex and hyperlocomotor behavior in T. gondii-infected mice. These results can contribute to elucidate the link toxoplasmosis with the establishment of neuroinflammatory response in neuropsychiatric disorders and to raise a discussion about the mechanisms related to changes in brain connectivity, with possible behavioral repercussions during chronic T. gondii infection.

中文翻译：

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弓形虫感染会破坏小鼠模型中的神经周围网。

背景技术与弓形虫病相关的行为和神经化学改变可能受到组织囊肿的持续存在和弓形虫感染宿主大脑中免疫反应激活的影响。脑细胞外基质被组织成神经元周围网 (PNN)，它们由一些神经元和神经胶质细胞释放和包裹。有证据表明，PNNs 损伤是一种与神经精神疾病相关的病理生理机制。然而，缺乏关于寄生虫感染对 PNN 完整性的影响以及这如何影响宿主行为的信息。目标 在此背景下，我们旨在分析弓形虫感染对囊肿负荷、PNN 完整性的影响，以及对慢性感染小鼠运动活动的可能影响。方法 我们用弓形虫 ME-49 菌株感染小鼠。三十天后，我们使用旷场测试评估动物的运动性能，然后评估四个大脑区域（初级和次级运动皮层、前额叶和感觉皮层）的囊肿负荷和 PNN 完整性，以使用紫藤凝集素评估 PNN 的完整性(WFA) 通过免疫组织化学分析进行标记。研究结果和主要结论 我们的研究结果揭示了大脑中囊肿的随机分布、大脑皮层四个区域神经元周围 PNN 的破坏以及弓形虫感染小鼠的过度运动行为。