Relationship between Helicobacter pylori and gastric carcinoma. -experimental study in H.pylori infected Mongolian gerbil model-

尽管“实验证据不足”，幽门螺杆菌仍被国际癌症研究机构和世界卫生组织归类为明确的人类致癌物质。为了获得关于这种关系的直接证据，我们利用幽门螺杆菌感染蒙古沙土鼠的模型研究了胃粘膜的组织病理学结果。分别于接种后1、2、3、6、12、18个月处死动物，进行组织学检查。所有感染动物的粘液和胃小窝内均可见螺旋菌，接种Hp后1个月可见多形核细胞和单核细胞在胃粘膜固有层内大量渗出。接种后2个月和3个月粘膜下层以单核细胞为主，并形成淋巴滤泡。接种后6个月，胃液旁幽门区出现胃溃疡、萎缩性胃炎和胃窦小弯处局限性肠化生，6个月后肠上皮化生加重，伴不典型增生。在接种幽门螺杆菌18个月后，5只感染动物中有2只出现了3例分化良好的胃腺癌。在整个观察期内，未感染的对照动物没有表现出异常的发现。本研究显示了幽门螺杆菌感染的蒙古沙土鼠的胃癌发生，并证实了IARC/WHO的报告，即幽门螺杆菌是一种明确的人类胃癌致癌物。

Helicobacter pylon is classified by IARC/WHO as a definite human gastric carcinogen, despite "inadequate experimental evidence". To obtain direct evidence concerning this relationship, we investigated the histopathological findings of gastric mucosa using a model of H.pylori infection in Mongolian gerbils. The animals were challenged p. o. with H.pylori ATCC-43504 and sacrificed at 1, 2, 3, 6, 12, and 18 months after inoculation for histological examination. The spiral bacteria were observed in the mucus and gastric pits of all infected animals.A severe infiltration of the lamina propria by polymorphonuclear and mononuclear cells was seen 1 month after H.pylori inoculation. The submucosa was infiltrated by mainly mononullear cells with formation of lymphoid follicles 2 and 3 months after inoculation. Gastric ulcer at the pyloric area in proximity to the fluidus, atrophic gastritis and focal intestinal metaplasia in the lesser curvature of the antrum appeared at 6 months after inoculation.Intestinal metaplasia became severe, with dysplasia, after that. At 18 mnoths after H.pylori inoculation, two of five infected animals showed three well-differentiated gastric adenocarcinomas. The uninfected control animals showed no abnormal findings throughout the entire observation period.This study shows gastric carcinogenesis in a H.pylori-infected Mongolian gerbil model and confirms the IARC/WHO report that H.pylori is a definite human gastric carcinogen.