Helicobacter pylori induces gastritis and intestinal metaplasia but no gastric adenocarcinoma in Mongolian gerbils.
OBJECTIVE
The Mongolian gerbil is considered as the model of choice when studying adenocarcinoma related to Helicobacter pylori infection. The purpose of this study was to compare two different H. pylori strains and elucidate whether adenocarcinomas developed in gerbils.


METHODS
Male gerbils were separated into three groups: one control and two groups infected with two different strains of H. pylori, TN2GF4 and SS1. At 3, 6, 12 or 18 months after inoculation 5 animals from each group were sacrificed. The stomach was used for culture, and for histology.


RESULTS
Inflammation was seen after 3 months in all the infected animals. In the controls no pathology was found at any time. Intestinal metaplasia was found in both the infected groups. Glands buried in the submucusal layer, changes that might be misinterpreted as adenocarcinoma, were found in 10% of the SS1 and in 65% of the TN2GF4 animals. Adenocarcinoma was not found in any of the gerbils.


CONCLUSIONS
All studies claiming to have found H. pylori-induced adenocarcinomas in gerbils describe atypical glands penetrating into the muscularis propria and interpret these as invasive growths due to cancer. An alternative interpretation is that the deranged glandular structures grow in and below the submucosa. It is suggested that atypical glands in the muscularis layer are not enough as a diagnostic criterion for gastric adenocarcinoma. It is concluded that adenocarcinoma has not yet been shown convincingly to develop in Mongolian gerbils infected with H. pylori. Nevertheless, it is a model well suited for studying gastritis, gastric ulcer and premalignant changes such as metaplasia.
Elfvin
Anders
A
Department of Gastrosurgical Research, Sahlgrenska Academy, Göteborg University, Sahlgrensky University Hospital. Box 75038, SE-400 36 Gothenburg, Sweden. anders.elfvin@vgregion.se
Bölin
Ingrid
I
Von Bothmer
Charlotte
C
Stolte
Manfred
M
Watanabe
Hidenobu
H
Fändriks
Lars
L
Vieth
Michael
M
D000230:Adenocarcinoma / Q000382:microbiology / Q000473:pathology; D000818:Animals; D001707:Biopsy, Needle; D004195:Disease Models, Animal; D005753:Gastric Mucosa / Q000382:microbiology / Q000473:pathology; D005756:Gastritis / Q000209:etiology* / Q000473:pathology; D005849:Gerbillinae; D016481:Helicobacter Infections / Q000150:complications*; D016480:Helicobacter pylori; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000382:microbiology / Q000473:pathology; D007414:Intestinal Neoplasms / Q000382:microbiology* / Q000473:pathology*; D008297:Male; D011897:Random Allocation; D012016:Reference Values; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013274:Stomach Neoplasms / Q000382:microbiology / Q000473:pathology