Auteurs : Alexis Audibert1,2, Xavier Mas-Orea2, Léa Rey2, Marcy Belloy1, Emilie Bassot1,Louise Battut2, Gilles Marodon3, Frederick Masson1, Matteo Serino2, Nicolas Cenac2,
Gilles Dietrich2, Chrystelle Bonnart2*☯, Nicolas Blanchard1*☯
Toxoplasma gondii is a common parasite that infects many people worldwide, often without causing noticeable symptoms. Gut infections can lead to long-term digestive issues, like post-infectious irritable bowel syndrome (PI-IBS). Although T. gondii is a gut infection agent, it has not been linked to PI-IBS so far. In this study performed in an experimental model, we examined how T. gondii latent infection affects the gut. We unexpectedly discovered that chronically infected mice experience less gut pain compared to uninfected animals. This effect is linked to the body’s natural pain-relief system, involving opioid molecules. This infection also led to long-lasting changes in immune cells of the gut, including T lymphocytes. Since T cells can produce opioids, we suspected them to play a role in the reduced pain phenotype. However, mice lacking a key opioid in their T lymphocytes still showed the same pain decrease, excluding this possible mechanism. In summary, these findings suggest that, unlike other gut infections, latent T. gondii infection may have a pain-relieving rather than a pain-inducing effect. They help better understand how infections influence gut health in unexpected ways, and in the future, they might contribute to decipher new pain control mechanisms.