Several studies demonstrate the protective effect of Trichinella spiralis (T. spiralis) on autoimmune diseases, however the optimal exposure time remains unexplored. This study aimed to determine whether pre-exposure of mice to T. spiralis conferred greater protection than introduction of the parasite in the acute phase of experimental colitis. We compared the effect of T. spiralis on dextran sodium sulfate (DSS)-induced colitis using two exposure paradigms: introduction three weeks prior to, or immediately after the induction period. Inflammation scores, morphological changes and cytokine profiles in serum and colonic tissue were assessed. At a parasite dose of 300 cysts, post exposure had a more pronounced effect on cytokine profiles, improved gross appearance of colon tissue, and reduced inflammatory symptoms. In addition, we demonstrate that regardless of cyst number, pre-exposure to T. spiralis did not confer protective benefits when compared to parasite introduction in the acute phase of DSS-induced colitis. Moreover, our data indicates that the underlying mechanisms of action involve an IL-17/TNF-alpha synergistic reaction, suppression of Th1 and Th2 responses, and an upregulation of the regulatory cytokines IL-10 and TGF-beta 1. Our results demonstrate that moderate exposure to T. spiralis in the acute phase of DSS-induced colitis improves disease associated inflammation and tissue disruption.

中文翻译：

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暴露时间决定了旋毛虫对实验性结肠炎的保护作用。

几项研究证明了旋毛虫（T. spinis）对自身免疫性疾病的保护作用，但最佳暴露时间仍未探索。本研究旨在确定在实验性结肠炎的急性期，小鼠预先暴露于螺旋线虫是否比引入寄生虫具有更大的保护作用。我们使用两种暴露范式比较了旋毛虫对葡聚糖硫酸钠 (DSS) 诱导的结肠炎的影响：在诱导期前三周或在诱导期后立即引入。评估了血清和结肠组织中的炎症评分、形态学变化和细胞因子谱。在 300 个包囊的寄生虫剂量下，暴露后对细胞因子谱有更显着的影响，改善了结肠组织的总体外观，并减少了炎症症状。此外，我们证明，无论囊肿数量如何，与 DSS 诱导的结肠炎急性期的寄生虫引入相比，预暴露于 T.spiralis 并没有带来保护益处。此外，我们的数据表明，潜在的作用机制涉及 IL-17/TNF-α 协同反应、Th1 和 Th2 反应的抑制以及调节性细胞因子 IL-10 和 TGF-β1 的上调。我们的结果表明在 DSS 诱导的结肠炎的急性期，适度接触螺旋线虫可改善疾病相关的炎症和组织破坏。