Preventive rather than therapeutic treatment with high fiber diet attenuates clinical and inflammatory markers of acute and chronic DSS-induced colitis in mice.

PURPOSE: Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with important impact on global health. Prebiotic and probiotic strategies are thought to be useful in the context of experimental IBD. Here, we compared the effects of preventive versus therapeutic treatment with a high fiber diet (prebiotic) in combination or not with Bifidobacterium longum (probiotic) in a murine model of chronic colitis. METHODS: Colitis was induced by adding dextran sulfate sodium (DSS) to drinking water for 6 days (acute colitis) or for 5 cycles of DSS (chronic colitis). RESULTS: Administration of the high fiber diet protected from acute colitis. Protection was optimal when diet was started 20 days prior to DSS. A 5-day pretreatment with acetate, a short-chain fatty acid, provided partial protection against acute colitis. In chronic colitis, pretreatment with the high fiber diet attenuated clinical and inflammatory parameters of disease. However, when the treatment with the high fiber diet started after disease had been established, overall protection was minimal. Similarly, delayed treatment with acetate or B. longum did not provide any protection even when the probiotic was associated with the high fiber diet. CONCLUSION: Preventive use of a high fiber diet or acetate clearly protects mice against acute and chronic damage induced by DSS in mice. However, protection is lost when therapies are initiated after disease has been established. These results suggest that any therapy aimed at modifying the gut environment (e.g., prebiotic or probiotic strategies) should be given early in the course of disease.

Suppressor of cytokine signaling 2 (SOCS2) contributes to encephalitis in a model of Herpes infection in mice.

The most severe manifestation of Herpes Simplex Type 1 virus (HSV-1) infection is encephalitis characterized by arousal impairment and seizures that can evolve to coma and death. Previous studies reported the involvement of suppressor of cytokine signaling (SOCS) proteins, specifically SOCS1 and SOCS3, in HSV-1 infection, suggesting that other members of this family could be involved in the immune response against HSV-1. No previous study has reported the role of SOCS2 in HSV-1 infection. In the current study, C57BL/6 wild-type mice (WT) and mice deficient in SOCS2 gene (SOCS2-/-) were subjected to intracranial inoculation with 102 plaque forming units (PFU) of HSV-1. Survival curve, neuroinflammatory parameters and neuropathology were evaluated. Infected SOCS2-/- mice had increased survival in comparison with infected WT animals. This better outcome was associated with reduced leukocyte infiltration, concentration of cytokines, and structural changes in the brain. SOCS2 seems to play a detrimental role in HSV-1 encephalitis. Moreover, the control of neuroinflammatory response in HSV-1 infection was of paramount importance to clinical outcome.