Sericic Acid Ameliorates DSS-induced Ulcerative Colitis in Mice by Modulating the NF-κB and Nrf2 Pathways

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease. In previous studies, we found extracts from the roots of Rosa odorata Sweet var. gigantea (Coll.et Hemsl.) Rehd. et Wils have a therapeutic effect on UC. Furthermore, sericic acid (SA) is a pentacyclic triterpenoid isolated from this plant that is being used for the first time. The purpose of this study was to investigate whether SA has anti-inflammatory and therapeutic effects on UC and its underlying mechanisms.

In this study, we used a dextran sulfate-induced UC mouse model and lipopolysaccharide (LPS)-induced inflammatory cell model along with an enzyme-linked immunosorbent assay (ELISA) to quantify the abundance of inflammatory factors and oxidative stress factors in tissues and cells. HE staining was used to analyze the therapeutic effect of the drugs on the UC mouse model. The expression levels of oxidative stress-related proteins were detected using immunoblotting and immunohistochemistry. The anti-inflammatory targets of SA were screened using protein chip arrays and verified by immunoblotting.

We found that SA had anti-inflammatory and antioxidant effects in animal and cellular inflammation models. SA inhibited the levels of NO, TNF-α, IL-6, IL-1β, and MDA in tissues and cells and upregulated the expression level of SOD. Animal experiments showed that SA alleviated the shortening of colon length and colon pathological damage caused by DSS. The antiinflammatory targets of SA were screened using protein chip arrays, and SA was found to inhibit proteins related to the NF-κB signaling pathway. Finally, immunoblotting and immunohistochemistry showed that SA downregulated the expression of p-IKKα/β and its downstream protein p-NF-κB, while promoting the expression of Nrf2 and its downstream protein HO-1.

The above results indicated that SA alleviated DSS-induced colitis by inhibiting NF-κB signaling pathway and activating Nrf2 pathway.