TNBS-induced colitis model

Trinitrobenzene sulfonic acid (TNBS)-induced colitis are well-established models to study mucosal inflammation. The colitis model was established in the IBD center, First Affiliated Hospital, Sun Yat-sen University, following the procedure as previously reported [59]. Briefly, pathogen-free male BALB/c mice (6–8 weeks) were obtained from Slack Jingda Experimental Animal LTD of Hunan province (Hunan, China) and maintained under specific pathogenic-free conditions in the animal facilities of Sun Yat-Sen University. Animals were pre-sensitized with 1 % trinitrobenzene sulfonic acid (TNBS, Sigma, St Louis, MO, USA) at day 1, and received 2.5 % TNBS (mixing 1 volume of 5 % (w/v) TNBS with 1 volume of absolute ethanol) (2.5 mg/20 g, about 100 μL) intrarectally at day 8 [59].

In our pilot studies, we tested different doses of anti-IL23P19 and found that intraperitoneal injection of anti-IL23P19 at the dose of 0.5 mg/kg yielded the best therapeutic effect. This dose was thus used for the following study. Experimental animals were divided into three groups (10 mice per group). In Group 1, animals received TNBS dissolved in ethanol. Twenty-four hours after administration of TNBS, animals were treated with a neutralizing anti-mouse IL23 antibody (anti-IL23P19, Clone: G23-8; eBioscience) via intraperitoneal injection (0.5 mg/kg) for three consecutive days (TNBS + P19). In Group 2, after receiving TNBS, animals were treated with the isotype control (TNBS + ISO). In Group 3, animals received 100 μL of 50 % ethanol alone as the negative control (Control).