Objective: To determine the changes of IL-8 and IL-8 mRNA in gastric and duodenal mucosa of children with Hp infection, to study the effect of Helicobacter pylori (Hp) infection on the expression of IL-8 and IL-8 mRNA, and to evaluate its possible roles in the pathogenesis of gastric and duodenal mucosal inflammation in Hp related gastroduodenal diseases.
Methods: Biopsy specimens were taken from the antral and duodenal mucosa on endoscopy in patients with or without Hp infection, which was diagnosed by urease test and Warshing-Starry staining. The expression of IL-8 in gastric and duodenal mucosa was determined by ELISA, the expression of IL-8 mRNA was determined by using RT-PCR.
Results: Inflammation of gastric antral mucosa was more severe in Hp-positive group than in Hp-negative group. Active inflammation often existed on the basis of chronic inflammation in Hp-positive mucosa, and duodenal mucosa had mild chronic inflammation in Hp-positive group. Of 17 children who were not infected with Hp, 4 had pathologically normal gastric mucosa and had mild chronic gastritis, one child had an active chronic gastritis. Nineteen children were infected with Hp and all had chronic gastritis with signs of active inflammation. Gastric and duodenal mucosal IL-8 and IL-8 mRNA were higher in HP infected than in non infected children (IL-8: in gastric mucosa 24.66 - 177.77 pg/mg, 2.94 - 12.98 pg/mg, t = 12.34, P < 0.01; in duodenal mucosa: 4.28 - 47.76 pg/mg, 2.04 - 9.52 pg/mg, t = 7.18, P < 0.01. IL-8 mRNA: in gastric mucosa 2.37 - 4.99, 0.05 - 0.44, t = 29.29, P < 0.01; in duodenal mucosa 1.22 - 1.87, 0.01 - 0.23, t = 37.20, P < 0.01). Children with active chronic gastritis had higher interleukin-8 levels and IL-8 mRNA expression than those with inactive gastritis (IL-8 in gastric mucosa: 12.98 - 177.77 pg/mg, 2.04 - 10.43 pg/mg, t = 10.66, P < 0.01; in duodenal mucosa: 5.28 - 47.76 pg/mg, 3.19 - 8.14 pg/mg, t = 6.52, P < 0.01. IL-8 mRNA in gastric mucosa: 0.51 - 4.99, 0.01 - 0.44, t = 18.62, P < 0.01; in duodenal mucosa: 0.23 - 1.87, 0.01 - 0.20, t = 19.10, P < 0.01).
Conclusion: Higher expression of IL-8 and IL-8 mRNA was seen in Hp-positive gastric and duodenal mucosa and in active gastritis. IL-8 may play an important role in the local gastric and duodenal mucosal inflammatory infiltration with a large number of neutrophils when there is Hp infection.