Sigma-1 Receptor Engages an Anti-Inflammatory and Antioxidant Feedback Loop Mediated by Peroxiredoxin in Experimental Colitis

Inflammatory bowel disease (IBD), comprising Crohn’s disease (CD) and ulcerative colitis (UC), is a chronic inflammatory condition of the gastrointestinal tract. Since the treatment of IBD is still an unresolved issue, we designed our study to investigate the effect of a novel therapeutic target, sigma-1 receptor (σ1R), considering its ability to activate antioxidant molecules. As a model, 2,4,6-trinitrobenzenesulfonic acid (TNBS) was used to induce colitis in Wistar–Harlan male rats. To test the beneficial effects of σ1R, animals were treated intracolonically (i.c.): (1) separately with an agonist (fluvoxamine (FLV)), (2) with an antagonist of the receptor (BD1063), or (3) as a co-treatment. Our results showed that FLV significantly decreased the severity of inflammation and increased the body weight of the animals. On the contrary, simultaneous treatment of FLV with BD1063 diminished the beneficial effects of FLV. Furthermore, FLV significantly enhanced the levels of glutathione (GSH) and peroxiredoxin 1 (PRDX1) and caused a significant reduction in 3-nitrotyrosine (3-NT) levels, the effects of which were abolished by co-treatment with BD1063. Taken together, our results suggest that the activation of σ1R in TNBS-induced colitis through FLV may be a promising therapeutic strategy, and its protective effect seems to involve the antioxidant pathway system.