幽门螺杆菌培养滤液诱癌和促癌作用的实验研究

目的观察大鼠胃粘膜在幽门螺杆菌（Ｈｐ）培养滤液长期作用下的组织学变化及其对大鼠实验性胃癌的促癌作用。方法分别以０．２５％和０．５％的Ｈｐ培养滤液让大鼠自由饮用,观察不同时间大鼠胃粘膜厚度、表面粘液含量、ＤＮＡ合成速率及组织学变化;并观察不同时相应用Ｈｐ培养滤液对甲基硝基亚硝基胍（ＭＮＮＧ）诱癌的促癌作用。结果实验第５周时,实验组大鼠胃粘膜厚度明显变薄,表面粘液含量减少和ＤＮＡ合成速率加快,随实验时间的延长,上述改变进一步加重。至５２周实验结束时,０．５％Ｈｐ培养滤液组大鼠腺胃粘膜肠化生、硫酸粘液阳性肠化生和异型增生的发生率（５７％、３９％、１８％）明显高于０．２５％Ｈｐ培养滤液组（２８％、１０％、３％）和正常对照组（７％、０％、０％）。无论在给予ＭＮＮＧ以前、同时或以后饮用Ｈｐ培养滤液,大鼠胃癌和癌前病变的发生率均明显增加。结论Ｈｐ的毒性产物可能具有直接的诱癌和促癌作用

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 mannner. 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.Conclusion Hp cytotoxin(s) may have direct carcinogenetic and tumor promoting effects.