Therapeutic effects of triptolide via the inhibition of IL-1β expression in a mouse model of ulcerative colitis

The present study aimed to investigate the effect of triptolide (TL) on ulcerative colitis (UC) and explore the potential association between the therapeutic effects of TL and IL-1β expression using a 4,4-dimethyl-4-silapentane-1-sulfonic acid (DSS)-induced mouse model to simulate human UC. A total of 70 BALB/c female mice were randomly allocated into seven equal groups: Group A, blank control; group B, normal saline injection; group C, propylene glycol injection; group D (TL1), 0.2 mg/kg TL; group E (TL2), 0.4 mg/kg TL; group F (TL3), 0.6 mg/kg TL; and group G, dexamethasone injection. Mice activity, diet and stool characteristics were recorded daily. Mice were sacrificed by cervical dislocation on day 8, and disease activity indices, colon tissue histological scores and colonic histopathological scores were subsequently calculated. Serum levels of IL-1β were evaluated by enzyme-linked immunosorbent assay, and IL-1β expression levels were examined by reverse transcription-quantitative polymerase chain reaction with colonic mucosa specimen at the gene level and western blot analysis at the protein level. The IL-1β mRNA and protein expression levels were significantly elevated in the normal saline injection and propylene glycol injection groups compared with the blank control group and (P<0.01). In TL (TL2 and TL3)- and dexamethasone-treated mice, IL-1β expression levels were significantly decreased, as compared with the normal saline and propylene glycol injection groups (P<0.05). No significant difference was detected between TL (TL2 and TL3) and dexamethasone treatments. The results of the present study indicated that IL-1β expression was upregulated in the UC mouse model, which may be associated with the development and progression of UC. Furthermore, TL inhibited IL-1β expression, suggesting that TL may be a novel therapeutic target for the treatment of UC.