Diacetylrhein, an anthraquinone antiarthritic agent, suppresses dextran sodium sulfate-induced inflammation in rats: A possible mechanism for a protective effect against ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory life-threatening and premalignant disorder with no cure that even might end up with surgical removal of a large section or even all of the colon. It is characterized by relapsing-remitting courses of intestinal inflammation and mucosal damage in which oxidative stress and exaggerated inflammatory response play a significant role. Most of the current medications to maintain remission are symptomatic and have many adverse reactions. Therefore, the potential for improved management of patients with UC continues to increase. Yet, the benefits of using the antiarthritic agent diacetylrhein to counteract inflammation in UC are still obscure. Hence, our study was designed to explore its potential role in UC using a model of dextran sodium sulfate-induced acute colitis in rats. Our results revealed that diacetylrhein targeted the NLRP3 and inhibited the inflammasome assembly. Consequently, caspase-1 activity and the inflammatory cytokines IL-1β and IL-18 were inhibited leading to a curbed pyroptosis process. Additionally, diacetylrhein revealed a significant antiapoptotic potential as revealed by the levels of pro-apoptotic and anti-apoptotic proteins. Concomitant to these effects, diacetylrhein also interrupted NFκB signals leading to improved microscopic features of inflamed colon and decreased colon weight to length ratio, indices of disease activity, and macroscopic damage. Additionally, a reduction in the myeloperoxidase activity, IL-6, and TGF-β alongside an increase in the gene expression of Ocln and ZO-1 were detected. To conclude diacetylrhein showed a significant antioxidant and anti-inflammatory potential and therefore might represent a promising agent in the management of acute UC.