RESUMO
OBJECTIVE@#To investigate the protective effect of procyanidin B2 (PCB2) on the intestinal barrier and against enteritis in mice with trinitrobenzene sulphonic acid (TNBS)-induced colitis and explore the possible mechanism.@*METHODS@#A mouse model of TNBS-induced colitis was established in male Balb/c mice aged 6-8 weeks. The successfully established mouse models were randomly divided into PCB2 treatment group (=10) and model group (=10) and were treated with daily intragastric administration of PCB2 (100 mg/kg, 0.2 mL) and 0.2 mL normal saline, respectively. After 4 weeks, the disease symptoms, intestinal inflammation, intestinal mucosal cell barrier function and the changes in PI3K/AKT signaling were evaluated using HE staining, immunofluorescence assay and Western blotting.@*RESULTS@#The disease activity index of the mice was significantly lower and the mean body weight was significantly greater in PCB2 group than in the model group in the 3rd and 4th weeks of intervention ( < 0.05). The levels of colonic inflammation and intestinal mucosal inflammatory mediators IL-1β and TNF-α were significantly lower while IL-10 was significantly higher in PCB2 group than in the model group ( < 0.05). Compared with those in the model group, the mice in PCB2 treatment group showed a significantly lower positive rate of bacterial translocation in the mesenteric lymph nodes and a lower thiocyanate-dextran permeability of the intestinal mucosa ( < 0.05). Western blotting showed that PCB2 treatment significantly increased the expressions of claudin-1 and ZO-1 ( < 0.05) and significantly lowered the expression levels of p-PI3K and p-AKT in the intestinal mucosa as compared with those in the model group ( < 0.05).@*CONCLUSIONS@#PCB2 suppresses intestinal inflammation and protects intestinal mucosal functions and structural integrity by inhibiting intestinal PI3K/AKT signaling pathway, suggesting the potential of PCB2 as a new drug for Crohn's disease.