A moderately elevated soy protein diet mitigates inflammatory changes in gut and in bone turnover during chronic TNBS-induced inflammatory bowel disease

Inflammatory bowel disease is a condition that leads to gut pathologies such as abnormal lymphatic architecture, as well as to systemic comorbidities such as bone loss. Furthermore, current therapies are limited to low efficacy and incur side effects. Dietary interventions have been explored minimally, but may provide a treatment for improving gut outcomes and comorbidities. Indeed, plant-based soy protein has been shown to exert anti-inflammatory effects. Here, we tested the impact of a moderately elevated soy protein diet in a chronic, 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model on gut and bone inflammatory-mediated pathophysiological adaptations. Colitis was induced by intrarectal administration of TNBS. Gut histopathology was scored, and lymphatic structural changes and the local inflammatory state were assessed via immunofluorescence. In addition, the effects of gut inflammation on bone turnover and osteocyte proteins were determined via histomorphometry and immunohistochemistry, respectively. The moderately elevated soy protein diet produced improvements in both colonic and bone tissues. In TNBS animals given the soy protein intervention, colon histological scores were reduced and the abnormal lymphatic architecture resolved. There were also improvements in bone formation and reduced bone resorption. In addition, TNBS increased inflammatory cytokines such as tumor necrosis factor-α and receptor activator of nuclear factor κ-B ligand in the gut and bone, but this was resolved in both tissues with the dietary soy protein intervention. The moderately elevated soy protein diet mitigated gut and bone inflammation in a chronic, TNBS-induced colitis model, demonstrating the potential for soy protein as a potential anti-inflammatory dietary intervention for inflammatory bowel disease.