Another study 576 investigated the effects of SM and L-arginine (L-Arg) on IBD progression in a TNBS-induced colitis rat model, finding that both treatments ameliorated colitis symptoms, decreased serum TNF-α levels, inhibited colonic iNOS, NF-κB, and cytochrome c expression, and increased HSP70 expression. This evidence concerns the gene NOS2 and irritable bowel syndrome.