Acid regulates inflammatory response in a rat model of induction of gastric ulcer recurrence by interleukin 1beta.
BACKGROUND
In a previous study we showed that interleukin 1beta (IL-1beta) caused recurrence of gastric ulcers in rats, and that adhesion molecules (intercellular adhesion molecule 1 and leucocytic beta2 integrins) play a role in this recurrence. Although gastric acid plays an important role in many types of gastric injuries, including peptic ulcer recurrence, the mechanism(s) remains unclear.


OBJECTIVE
To examine the involvement of gastric acid in induction of ulcer recurrence by IL-1beta, and to investigate the role of gastric acid in inflammatory responses during ulcer recurrence.


METHODS
Rats with healed ulcers were used. Rats were given 1 microg/kg IL-1beta intraperitoneally. Another group of rats was given 20 mg/kg omeprazole for three days to inhibit acid secretion, and received IL-1beta 20 hours after the first administration of omeprazole. They were then given 0.15 N HCl or vehicle at 0, 12, 24, and 36 hours after IL-1beta treatment. Some rats were given acid alone at the same time points. Expression of adhesion molecules was examined immunohistochemically and concentrations of IL-1beta and tumour necrosis factor alpha (TNF-alpha) were measured by ELISA in scar tissue 24 hours after IL-1beta treatment.


RESULTS
IL-1beta increased expression of adhesion molecules and concentrations of IL-1beta and TNF-alpha in scar tissue by 24 hours after IL-1beta treatment, and nine of 11 healed ulcers had recurred by 48 hours. Omeprazole inhibited the effects of IL-1beta. HCl acid abolished the inhibitory effects of omeprazole. Acid alone affected neither expression of adhesion molecules nor cytokine concentrations, and did not cause recurrence.


CONCLUSIONS
Gastric acid is required for recurrence of gastric ulcers caused by IL-1beta, and gastric acid stimulates the inflammatory process in scarred mucosa during ulcer recurrence.
Watanabe
T
T
Department of Biosignal Analysis, Osaka City University Medical School, Osaka 545-8585, Japan. watanabe@med.osaka-cu.ac.jp
Higuchi
K
K
Tominaga
K
K
Fujiwara
Y
Y
Arakawa
T
T
D000704:Analysis of Variance; D000818:Animals; D000897:Anti-Ulcer Agents / Q000627:therapeutic use; D004797:Enzyme-Linked Immunosorbent Assay; D005744:Gastric Acid / Q000378:metabolism*; D006851:Hydrochloric Acid / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D007375:Interleukin-1 / Q000032:analysis / Q000502:physiology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D016177:Macrophage-1 Antigen / Q000378:metabolism; D008297:Male; D009853:Omeprazole / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D012008:Recurrence; D013047:Specific Pathogen-Free Organisms; D013276:Stomach Ulcer / Q000188:drug therapy / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis
D000897:Anti-Ulcer Agents; D007375:Interleukin-1; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D009853:Omeprazole; D006851:Hydrochloric Acid