Objective: To observe the changes of inflammatory cytokines and calprotectin (CP) in the rat model of ulcerative colitis (UC) and investigate the mechanism of the inflammatory response.
Methods: Twenty rats were randomly divided into normal control (NC) group and model (MC) group, with 10 rats in each group. The rats of MC group were given through the intestinal tract the mixed solution of 2, 4, 6 trinitrobenzene sulfonic acid (TNBS)/ethanol to induce UC. The rats of NC group were given normal saline instead. Three weeks after modeling, the changes of colon tissue morphology were observed with HE staining. The levels of interferon gamma (INF-γ), interleukin (IL)-4, IL-10, IL-12 and CP in serum were detected by ELISA. The expressions of INF-γ, IL-4, CP of colon tissue were detected by Western blotting.
Results: Indicators of inflammatory activity were significantly elevated, and colon tissue injury was seen in MC group. Compared with the NC group, the expressions of INF-γ, IL-12 and CP of serum increased in the MC group (P<0.05 or P<0.01). The expressions of IL-4 and IL-10 in the MC group were lower than those in the NC group (P<0.01). Compared with the NC group, the expressions of INF-γ and CP of colon tissue significantly increased (P<0.01 or P<0.05), and the expression of IL-4 decreased in the MC group (P<0.05). Correlation analysis showed that there was a positive correlation between CP and IFN-γ, and a negative correlation between CP and IL-4 (P<0.05).
Conclusion: Increased CP in UC rats can promote the expression of inflammatory factors, lead to the imbalance of Th1/Th2 cells, and enhance inflammatory responses. These factors promote the occurrence and development of UC.