The expression levels of IL-6, IL-1b, IL-8, IL-10, TNF-α, and NO in rat small intestinal mucosa were measured by ELISA. *P<0.05, **P<0.01 versus sham group; #P<0.05 versus MDP group. NO, nitric oxide; ELISA, enzyme-linked immunosorbent assay; MDP, muramyl dipeptide.