Involvement of cyclooxygenase-2 in hyperplastic gastritis induced by Helicobacter pylori infection in C57BL/6 mice.
OBJECTIVE
The hyperplastic changes observed in Helicobacter pylori-associated gastritis have been considered to increase the risk of gastric cancer. The aim of this study was to determine whether cyclooxygenase-2 is involved in the hyperplastic changes in mice infected with H. pylori.


METHODS
Seven-week-old, male C57BL/6 mice (n=40) were inoculated with the Sydney strain of H. pylori. Control mice (n=40) were treated with vehicle only. Half of the infected and control mice were fed an experimental diet containing etodolac (10 mg/kg/day) from 1 week after inoculation until the end of the experiment. The thickness of gastric pits, COX-2 mRNA and protein levels, and prostaglandin E2 (PGE2) levels in the gastric mucosa were determined before and 12, and 24 weeks after inoculation.


RESULTS
The thickness of gastric pits, COX-2 mRNA and protein levels, and PGE2 levels were significantly increased at 24 weeks after inoculation of H. pylori compared with the control groups. Treatment with etodolac resulted in significant decreases in PGE2 production and in the thickness of gastric pits in the infected groups at 24 weeks after inoculation.


CONCLUSIONS
Our findings suggest that COX-2 is involved in the development of hyperplastic gastritis caused by H. pylori infection via the production of PGE2.
Xiao
F
F
First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Furuta
T
T
Takashima
M
M
Shirai
N
N
Hanai
H
H
D000818:Animals; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000096:biosynthesis; D005753:Gastric Mucosa / Q000473:pathology*; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori / Q000472:pathogenicity*; D006965:Hyperplasia; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000209:etiology
D007527:Isoenzymes; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone