[The carcinogenetic and tumor-promoting effects of concentrated Helicobacter pylori culture supernatant in rats].
OBJECTIVE
To investigate the carcinogenetic and tumor-promoting effect of concentrated Helicobacter pylori culture supernatant (CHCS).


METHODS
0.25% and 0.5% CHCS in drinking water administered orally for 52 weeks in rats, the changes of mucosal thickness, adherent mucosal mucus amount, DNA synthesis rate and precancerous lesions incidence in different times were examined, and the promoting effect of CHCS used in different periods on experimental carcinogenesis induced by MNNG was also clarified.


RESULTS
Decreased mucosal thickness and amount of mucosal adherent mucus, increased DNA synthesis were found after CHCS feeding for 5 weeks in a dose- and time-dependent manner. By the end of the experiment at the 52nd week, the incidence of intestinal metaplasia(IM), sulfomucin positive IM and dysplasia in 0.5% CHCS group(57%, 39%, 18% respectively) were significantly higher than those in 0.25% CHCS group(28%, 10%, 3% respectively) and control group(7%, 0%, 0% respectively). Whenever CHCS was used prior to, together with, or following MNNG administration, the incidences of gastric cancer and precancerous lesions were significantly increased in comparison with those in the rats treated with MNNG alone.


CONCLUSIONS
Hp cytotoxin(s) may have direct carcinogenetic and tumor-promoting effects.
Liang
H
H
Department of Gastroenterology, Southwest Hospital, Third Military Medical University, Chongqing.
Liu
W
W
Fang
D
D
D000818:Animals; D002273:Carcinogens; D003470:Culture Media; D005753:Gastric Mucosa / Q000473:pathology; D016480:Helicobacter pylori / Q000472:pathogenicity*; D008297:Male; D011230:Precancerous Conditions / Q000382:microbiology* / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013274:Stomach Neoplasms / Q000382:microbiology* / Q000473:pathology
D002273:Carcinogens; D003470:Culture Media