Non-encapsulated Trichinella spp., T. papuae, diminishes severity of DSS-induced colitis in mice.

Background: Helminths use various mechanisms to avoid host immunity and protect themselves from being eliminated. Despite evading host immune responses, immunosuppression and regulation mechanisms elicit functions that diminish the adverse effects of unrelated inflammatory diseases.

Objective: We investigated whether helminthic infections can ameliorate inflammatory diseases.

Methods: Mice were infected with Trichinella papuae and then subjected to induced colitis through the oral administration of dextran sulfate sodium (DSS). Macroscopic and microscopic examinations measured weight loss, stool consistency, gross bleeding, colon length, and tissue inflammation. In addition, cytokine expression was observed in colon tissue by SYBR real-time RT-PCR to investigate the Th1, Th2, and regulatory cytokines.

Result: The results showed that T. papuae infection decreased the severity of DSS-inducedcolitis, including weight loss, bloody diarrhea, shortening of colon, and colon tissue damage in mice (p <0.05). The expression level of IL-4 was high in the colons of DSS-treated mice without helminthic infection, while infected mice with DSS treatment had lower IL-4 levels (p <0.05). Uninfected DSS-treated mice failed to produce IL-10 mRNA in colon tissue, which may cause more severe colitis. In contrast, prior T. papuae infection DSS-treated mice had IL-10 levels in the colon significant lower than the normal and infected control groups.

Conclusion: Our data provide the evidence that prior T. papuae infection can ameliorate DSS-induced colitis in mice and may be considered for a novel therapeutic strategy against immunological diseases in the future.