Effects of pro-inflammatory cytokines and antioxidants expression in the jejunum of mice induced by hydrogen peroxide

Inflammation-induced jejunal cell death and oxidative stress have been observed in inflammatory bowel disease (IBD), but now, there is still no systematic animal model of jejunal oxidative stress for the evaluation of potential therapies. Thus, the purpose of this study was to evaluate the dynamic changes of pro-inflammatory cytokines and antioxidant expression on the jejunal inflammation. In this study, Hydrogen peroxide(H2O2, 10 ml/kg)was administrated intragastrically to mice in a single dose of 1%, 3%, or 5%. The incidence of death, histomorphometry, inflammatory cytokines (including TNF-α,IL-1β,and IL-5), and antioxidant genes were measured via RT-PCR. During the whole period, a massive infiltration of neutrophils was observed in the jejunum. Intragastric administration of H2O2 significantly up-regulated the expression of TNF-α,IL-1β, and IL-5 (P < 0.05). Meanwhile, 5% H2O2 induced an acute stress in mice which lasted up to 3 days, while 3% H2O2 induced a chronic injury in the jejunum that lasted 7 days. In the early stage, H2O2 markedly enhanced expression of antioxidant genes and all of the doses used progressively decreased the expression of antioxidant genes in a time-dependent manner. These findings suggested that intragastric administration of 3% H2O2 induces relatively stable oxidative stress in the jejunum.