幽门螺杆菌感染对胃上皮细胞增殖影响的实验研究

目的在幽门螺杆菌(H.pylori)长期感染蒙古沙土鼠腺胃模型基础上,探讨H.pylori感染诱致胃癌发生的可能机制.方法采用H.pylori国际标准菌株NCTC11637灌喂蒙古沙土鼠,建立H.pylori长期感染动物模型;用免疫组化及原位杂交方法检测H.pylori感染致胃上皮细胞增殖的改变.结果成功建立了H.pylori长期感染蒙古沙土鼠腺胃模型,其胃粘膜的组织学变化显示,H.pylori感染可致正常胃粘膜→慢性胃炎→萎缩→肠化生→异型增生的发展过程.H.pylori感染对胃上皮细胞增殖的影响:H.pylori感染能引起胃窦上皮细胞增殖增加(P<0.05);随着H.pylori感染时间的增加,EGF mRNA及EGFR mRNA的阳性信号表达呈逐渐增加的趋势(P<0.05) H.pylori定植致胃窦上皮细胞增殖的异常,对正常胃窦粘膜向不典型增生进展的过程起重要作用:EGF及EGFR在mRNA水平的异常表达可能是H.pylori定植致胃窦上皮细胞增殖异常的重要原因。     

幽门螺杆菌长期感染蒙古沙土鼠腺胃模型的建立及评价

目的 建立幽门螺杆菌（Helicobacter pylori,Hp）长期感染蒙古沙土鼠腺胃模型,验证该模型出现的病理改变及腺胃肿瘤的发生情况。方法 采用国际标准菌株NCTC 11637灌喂蒙古沙土鼠,建立HP长期感染蒙古沙土鼠腺胃模型。结果 成功建立了HP长期感染蒙古沙土鼠腺胃模型,其胃黏膜的组织学变化显示,HP感染可致正常胃黏膜→慢性胃炎→萎缩→肠化生→异型增生的发展过程,Hp NCTC 11637定植于蒙古沙土鼠腺胃65财哩,可引起胃黏膜出现严重的萎缩、肠化生及不典型增生等胃癌前状态,暂未发现早期癌。结论 Hp NCTC 11637易长期定植于蒙古沙土鼠腺胃,模型的稳定性及重复性极佳,且与Hp感染人胃黏膜后出现的各种病理变化极为相似。     

沙土鼠感染幽门螺杆菌后胃粘膜病理学改变的研究

目的和方法:应用HP标准菌株ATCC43504,增菌培养后接种于6周龄沙土鼠胃内。分别于2周、12周后杀死实验鼠。鼠胃经过福尔马林固定,石蜡切片,进行HP组化染色、AB/PAS染色及Brdu.PCNA免疫组化染色。结果:接种HP2周后,胃粘膜上皮细胞间有中性粒细胞、淋巴细胞浸润,上皮细胞及腺窝内可见大量HP存在,AB/PAS染色处见肥大细胞增多。Brdu.PCNA呈阳性表达,明显高于对照组。接种HP12周后,胃窦部出现溃疡(2/3),胃粘膜上皮细胞可见核分裂相及淋巴滤泡。结论:①接种HP2周后的沙土鼠胃粘膜呈急性炎症改变,HP定植于胃窦粘膜呈慢性炎症改变。提示沙土鼠是研究HP感染性胃病有价值的动物模型;②HP感染性胃粘膜Brdu.PCNA呈阳性高表达,表明HP感染过程中,伴有细胞部增值性变化。     

幽门螺杆菌相关性胃炎和胃癌前期病变的发病机制

幽门螺杆菌（H．pylori）感染诱发胃黏膜的炎症反应是引起一切病变的基础，并且它在慢性胃炎→萎缩性胃炎→胃黏膜肠上皮化生→不典型增生→胃癌的演变过程中至始至终起作用，因此H．priori相关性胃炎是H．priori致病的启动因子。H．priori感染可引起胃黏膜局部固有和获得性免疫异常，炎症介质的释放、ROS和NO含量的异常，胃上皮细胞增殖与凋亡失衡，端粒酶及相关基因表达异常。这些因素综合作用引起胃黏膜炎症，并且由其发展为胃癌前病变，最终导致胃癌发生。     

乳酸杆菌对蒙古沙鼠幽门螺杆菌感染性胃炎的疗效及其机制

目的: 观察乳酸杆菌对蒙古沙土鼠H Pylori 感染性胃炎的治疗作用,探讨乳酸杆菌防治H pylori感染的作用机制.方法: 通过接种H pylori,建立蒙古沙土鼠H pylori感染性胃炎动物模型,将造模成功的32只蒙古沙土鼠随机分为4组,每组8只.第1组(抗生素加质子泵抑制剂干预治疗组)、第2组(乳酸杆茵治疗组)、第3组(乳酸杆菌加质子泵抑制剂治疗组)、第4组(生理盐水对照组),用相应干扰剂分别连续灌胃治疗10 d.另8只正常蒙古沙土鼠为第5组(空白对照组).最后1次灌胃4 wk后处死沙鼠,HE染色判断鼠胃黏膜组织学损伤,并用快速尿素酶试验、Giemsa染色和细菌培养进行Hpylori的检测,免疫组化检测胃黏膜中IL-6、COX-2、和TNF-α蛋白的表达.结果: 第1组、第2组和第3组之间蒙古沙土鼠的H pylori根除率无显著差异,但均比第4组的根除率低,之间差异有显著性(87.5%,75%,75%vs100%,均P<0.05).第1组、第2组和第3组蒙古沙土鼠的胃体、胃窦和十二指肠各部位组织胃黏膜慢性炎症评分与第4组相比显著下降(胃体:1.8±0.54,2.0±0.48,1.9±0.50vs4.2±1.06,均P<0.05;胃窦:1.5±0.27,1.4±0.33,1.7±0.46vs4.6±0.74,均P<0.05:十二指肠:1.4±0.41,1.7±0.29,1.6±0.52vs4.1±0.83,均P<0.05).第1组、第2组和第3组蒙古沙土鼠三种炎症因子表达与第4组相比显著下降(COX-2:3.57±0.32,3.89±0.51,2.95±0.76vs6.79±1.68,均P<0.05:IL-6:2.42±0.60,2.28±0.7l,1.93±0.52vs5.61±0.28,均P<0.05;TNF-α:3.30±0.52,3.65±0.35,2.84±0.20vs6.76±1.63,均P<0.05).结论: 乳酸杆菌治疗蒙古沙鼠Hpylori感染性胃炎模型的疗效与PPI加抗生素三联疗法相当;并可显著降低沙鼠胃黏膜的COX-2、IL-6、TNF-α的表达.     

幽门螺杆菌感染与胃不同部位组织学病变的关系

目的 明确幽门螺杆菌(Helicobacter pylori,H,pylori)感染与胃不同部位粘膜组织学病变的关系。方法 在215例胃镜受检者胃窦、角、体三点取材进行组织学检查，Giemsa染色明确H.pylori感染情况，HE染色计量观察组织学病变情况，分析两者的相关关系。结果 从胃窦到胃角、胃体，炎症程度(单个核细胞浸润)、活动度(中性粒细胞浸润)、糜烂及淋巴滤泡形成均递减，H.pylori阳性者积分高于阴性者。在胃窦和胃角部，H.pylori感染更常引起近腔面上皮分泌下降，而在胃体部无此发现，H.pylori感染在三个部位均可引起腺体萎缩。结论 H.pylori感染是胃多部位组织学病变如淋巴细胞、中性粒细胞浸润、糜烂和淋巴滤泡形成与粘膜萎缩的病因，在胃窦和胃角引起的病变重于胃体。     

幽门螺杆菌慢性感染诱导胃上皮细胞产生凋亡耐受

目的：建立幽门螺杆菌（H.pylori)慢性感染胃上皮细胞模型,并分析H.pylori慢性感染与胃上皮细胞凋亡的关系。方法：首先用H.pylori SS1与人非肿瘤性胃上皮细胞株GES－1共培养16周,建立GES－1模型细胞,然后采用流式细胞术分析这种模型细胞对H.pylori和其它肠道细菌以及抗肿瘤药物凋亡诱导剂的应答。结果：成功获得了H.pylori慢性感染胃上皮细胞模型（GES－1模型细胞）。这种模型细胞不仅对H.pylori诱导的凋亡耐受,而且对其他肠道细菌和一些凋亡诱导剂也是耐受的。结论：幽门螺杆菌慢性感染诱导胃上皮细胞产生凋亡耐受,由此可能增加了胃上皮细胞癌变的危险性。     

胃粘膜肠上皮化生CST—π的表达及其与H.pylori相关性研究

目的：探讨GST－π在胃癌发生过程中表达，及在肠化阶段在GST－π为代表的人体对致癌物解毒系统与H.pylori致毒作用间的相互作用。方法：利用S－P法对219例胃粘膜活检标本进行GST－π单克隆抗体的检测；利用HID－AbpH2.5-PAS粘蛋白组化学技术对171例肠化粘膜进行分型；利用HE及H.pylori-DNA PCR及ELISA方法对正常胃粘膜和肠化粘膜进行H.pylori的检测。对80例H.pylori阳性患进行H.pyrori根除治疗三个月后进行H.pylori、GST－π的检测。结果：正常胃粘膜未见GST－π的表达，肠化粘膜GST－π阳性率为69．5％，胃癌GST－π阳性率为44．4％，高于正常胃粘膜（P＜0．01），低于肠化粘膜（P＜0．05）。H.pylori阴性组SGT－π阳性率高于H.pylori阳性组（P＜0．05）。H.pylori根除治疗后，根除组GST－π表达高于未根除组（P＜0．05）。结论：正常胃粘膜→肠化粘膜→胃癌组织GST－π表达由无→高→低，GST－π弱阳性或阴性的Ⅲ型肠化与胃癌关系密切；肠化粘膜中GST－π弱阳性或阴性表达如合并H.pylori感染，胃癌发生的危险性增加，提示在肠化阶段H.pylori的致毒作用与机体对致癌物的解毒作用彼此相互拮抗。     

胃粘膜肠上皮化生CST-Л的表达及其与H.pylori相关性研究

目的探讨GST-Л在胃癌发生过程中表达,及在肠化阶段以GST-Л为代表的人体对致癌物解毒系统与H.pylori致毒作用间的相互作用.方法利用S-P法对219例胃粘膜活检标本进行GST-Л单克隆抗体的检测:利用HID-AbpH2.5-PAS粘蛋白组化学技术对171例肠化粘膜进行分型;利用HE及H.pylori-DNA PCR及ELISA方法对正常胃粘膜和肠化粘膜进行H.pylori的检测.对80例H.pylori阳性患者进行H.pylori根除治疗三个月后进行H.pylori、GST-Л的检测.结果正常胃粘膜未见GST-Л的表达,肠化粘膜GST-Л阳性率为69.6%,胃癌GST-Л阳性率为44.4%,高于正常胃粘膜(P＜0.01),低于肠化粘膜(P＜0.05).H.pylori阴性组SGT-Л阳性率高于H.pylori阳性组(P＜0.05).H.pylori根除治疗后,根除组GST-Л表达高于未根除组(P＜0.05).结论正常胃粘膜→肠化粘膜→胃癌组织GST-Л表达由无→高→低,GST-Л弱阳性或阴性的Ⅲ型肠化与胃癌关系密切;肠化粘膜中GST-Л弱阳性或阴性表达如合并H.pylori感染者,胃癌发生的危险性增加,提示在肠化阶段H.pylori的致毒作用与机体对致癌物的解毒作用彼此相互拮抗.     

幽门螺杆菌感染对胃粘膜上皮细胞增殖的影响

目的观察幽门螺杆菌(H.Pylori)感染者,特别是vacAs1a型菌株感染者胃粘膜上皮细胞的增殖情况.方法取84例慢性浅表性胃炎(CSG)和16例十二指肠溃疡(DU)患者的胃窦粘膜标本检测H.Pylori,用溴脱氧尿苷掺入免疫组化法标记S期细胞并计算增殖标记指数(LI),用聚合酶链反应(PCR)检测vacAs1a基因.结果H.Pylori阳性患者的胃粘膜上皮细胞增殖LI为6.14%±1.21%,显著高于H.pylori阴性者(2.43%±0.61%,P＜0.001).vacAs1a阳性者的LI为8.00%±1.46%,显著高于vacAs1a阴性者(4.51%±0.86%,P＜0.05)和H.pylori阴性者(P＜0.001).H.Pylori感染、胃粘膜上皮细胞增殖LI与胃粘膜炎症程度三者高度相关,而炎症程度与vacA类型无关.结论H.pylori感染者的胃粘膜上皮细胞增殖LI明显高于H.pylori阴性者;vacAsla型H.Pylori菌株和炎症程度是胃粘膜上皮细胞增殖的独立影响因素.     

Development of gastric adenocarcinoma in Mongolian gerbils after long-term infection with Helicobacter pylori

BACKGROUND AND AIM: The experimental evidence that long-term colonization of Helicobacter pylori results in the development of gastric cancer in Mongolian gerbils has been reported only by two Japanese groups to date. This study aimed to investigate the carcinogenicity of H. pylori infection in a Mongolian gerbil model. METHODS: Thirty-six Mongolian gerbils (inner Mongolian origin) were divided into two groups (male to female ratio, 1:1) and orally inoculated with a standard H. pylori strain (ATCC43504) or H. pylori161 (isolated from a Chinese patient with gastric adenocarcinoma), respectively, once a week for 5 weeks. Another 10 control gerbils were given phosphate-buffered saline. The animals were killed 8, 20, 28 and 84 weeks after inoculation for bacterial and histological examination. RESULTS: Seven inoculated gerbils died at the week 42. Overall, H. pylori colonization was detected in 24 (83%) of the 29 available inoculated gerbils. The gastric lesions were aggravated gradually over time. At week 84, moderate to severe gastritis, characterized by diffuse infiltration of mononuclear cells and formation of multiple lymphoid follicles in mucosa and submucosa, and even the lymphoepithelial lesions, were observed. Epithelial hyperplasia were dominant in almost all gerbils. Four (24%) of the 17 animals had hyperplastic polyps. Intestinal metaplasia were rarely seen (in three gerbils). Well-differentiated gastric adenocarcinomas developed in three (18%) of the 17 gerbils after 84 weeks. Of the three gerbils, one female gerbil was infected with H. pylori161 and the others (one male and one female) were infected with ATCC43504. CONCLUSIONS: The present study reconfirms that H. pylori infection alone can induce gastric adenocarcinoma in Mongolian gerbils and suggests that different species of gerbil and both standard and clinically isolated H. pylori strains can be used for investigating the carcinogenesis of H. pylori. This is the first report of the development of gastric cancer in female gerbils, which highlights the importance of using both sexes to investigate the pathogenesis of H. pylori and whether host susceptibility is influenced by sex.     

Comparative Analysis of Colonization of Helicobacter pylori and Glycolipids Receptor Density in Mongolian Gerbils and Mice

The Mongolian gerbil has been used as an excellent experimental animal model for studying Helicobacter pylori infection because it can stably colonize and induce severe chronic gastritis, ulceration, and cancer-simulating human diseases in this animal. In contrast, H. pylori can only induce mild inflammation in many mouse models. The aim in this study is to clarify the difference of induction of pathological lesions in the two animal models. SPF ICR mice and Mongolian gerbils were inoculated with a clinically isolated strain of H. pylori. Six weeks after inoculation, bacteria colonizing the stomach were counted. Immunohistochemical staining and biochemical analyses of three putative receptor glycolipids were performed with monoclonal antibodies to the respective glycolipids. Significantly higher numbers of H. pylori were recovered from the stomachs of Mongolian gerbils than mice (5.77 ± 0.46 log CFU vs 4.17 ± 0.55 log CFU, P < 0.01). Immunohistochemical studies showed that sulfatide expression in the gastric mucosa of Mongolian gerbils was much stronger than that in mice, whereas the expression of Lewis^b glycolipid and GM3 were almost equal. Quantitative analysis of each glycolipid by thin-layer chromatography confirmed the results of immunohistochemical study, showing 4.1 times higher sulfatide content in the Mongolian gerbil stomach. The content of both Lewis^b and GM3 was almost equivalent in these two animals. In conclusions, higher levels of sulfatide expression, a putative adhesion receptor, in the gastric mucosa of Mongolian gerbils may allow abundant colonization by H. pylori, resulting in the development of gastric lesions in this animal model.     

Helicobacter pylori-infected animal models are extremely suitable for the investigation of gastric carcinogenesis

Although various animal models have been developed to clarify gastric carcinogenesis, apparent mechanism of gastric cancer was not clarified in recent years. Since the recognition of the pathogenicity of Helicobacter pylori (H pylori), several animal models with H pylori infection have been developed to confirm the association between H pylori and gastric cancer. Nonhuman primate and rodent models were suitable for this study. Japanese monkey model revealed atrophic gastritis and p53 mutation after long-term infection of H pylori. Mongolian gerbil model showed the development of gastric carcinoma with H pylori infection alone, as well as with combination of chemical carcinogens, such as N-methyl-N-nitrosourea and N-methyl-N-nitro-N-nitrosoguanidine. The histopathological changes of these animal models after H pylori inoculation are closely similar to those in human beings with H pylori infection. Eradication therapy attenuated the development of gastric cancer in Hpylori-infected Mongolian gerbil. Although several features of animal models differ from those seen in human beings, these experimental models provide a starting point for further studies to clarify the mechanism of gastric carcinogenesis as a result of H pylori infection and assist the planning of eradication therapy to prevent gastric carcinoma.     

Overexpression of cyclin E in Mongolian gerbil With Helicobacter pylori—induced gastric precancerosis

AIM: To explore dysregulation of cyclin E in malignancies,and to further investigate the role of cyclin E in Helicobacterpylori ( H. pylori)-induced gastric precancerosis.METHODS: Four-week-old specific pathogen-free maleMongolian gerbils were employed in the study. 0.5 mL 1 ×108 cfu@ L- 1 suspension of H. pylori NTCC11637 in Brucellabroth was inoculated orally into each of 20 Mongolian gerbils, and a further 20 gerbils were inoculated with Brucella brothas controls. 10 of the infected gerbils and 10 of the non-infected control gerbils were sacrificed at 25, 45 wk afterinfection. The expression of cyclin E was analyzed by RT-PCR and immunohistochemical studies with monoclonalantibody to cyclin E in Mongolian gerbil of H. pylori-induced gastric precancerosis.RESULTS: H. pylori was constantly detected in all infectedanimals throughout the study. At 25 wk after infection of H.pylori, ulcers were observed in the antral and body ofstomach ( n = 6). Histological examination showed that allanimals developed severe inflammation and multifocallymphoid follicles appeared in the lamina propria andsubmucosa of gastric antrum. At 45 wk after infection of H.pylori, severe atrophic gastritis (n = 10), intestinalmetaplasia (n = 8) and dysplasia (n = 6) could beobserved. Cyclin E mRNA levels were significantly more at25 wk after infection of H. pylori (1.27±0.26), and at45 wkafter infection of H. pylori (1.82 ± 0.39 ) than control-animals (0.59 ± 0.20, P＜ 0.01) ; cyclin E mRNA levels wereevaluated by 2.2-fold at 25 wk ( P ＜ 0.01 ) and 3. 1-fold at 45wk ( P ＜ 0.01 ) precancarosis induced by H. pylori, whencompared with control gastric epithelium of Mongoliangerbil. Immunohistochemical staining revealed exclusivenuclear staining of cyclin E. Furthermore, there wes asequential increase in cyclin E positive cells from normalepithelium to precancerosis.CONCLUSION: Overexpression of cyclin E occurs relativelyearly in gastric tumorigenesis in this model.     

Helicobacter pylori alters gastric epithelial cell cycle events and gastrin secretion in Mongolian gerbils

BACKGROUND & AIMS: Human colonization with Helicobacter pylori increases the risk for distal gastric adenocarcinoma, possibly by altering gastric epithelial cell cycle events and/or gastrin secretion. This study aimed to determine whether H. pylori virulence-related characteristics affect apoptosis, proliferation, and gastrin levels in a rodent model of gastric adenocarcinoma. METHODS: Mongolian gerbils were challenged with H. pylori wild-type or isogenic cagA(-) and vacA(-) mutants, and apoptotic and proliferating cells were identified by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and proliferating cell nuclear antigen immunohistochemistry, respectively. Serum gastrin levels were determined by radioimmunoassay. RESULTS: Gastric epithelial cell turnover was no different after infection with the wild-type, cagA(-), or vacA(-) strains. H. pylori infection significantly increased antral apoptosis 2-4 weeks after challenge, before apoptotic indices decreased to baseline. In contrast, antral proliferation rates were significantly higher 16-20 weeks after inoculation, but then decreased by 40 weeks. Antral proliferation was significantly related to serum gastrin levels, whereas antral apoptosis was inversely related to acute inflammation and lymphoid follicles. CONCLUSIONS: In H. pylori-infected gerbils, enhanced antral apoptosis is an early and transient cell cycle event. Epithelial cell proliferation peaks later and is significantly related to increased gastrin levels, suggesting that epithelial cell growth in H. pylori-colonized mucosa may be mediated by gastrin-dependent mechanisms.     

脾虚蒙古沙土鼠感染幽门螺杆菌动物模型的建立

目的 :建立脾虚蒙古沙土鼠感染幽门螺杆菌 (Hp)动物模型 ,验证该模型出现的病理改变及 Hp定植情况。方法 :采用国际标准菌株 SS1灌喂利血平致脾虚蒙古沙土鼠 ,建立脾虚蒙古沙土鼠感染 Hp动物模型 (8只 ) ,检测胃粘膜 Hp定植量、炎症程度 ,并与脾虚组、Hp感染组及正常组 (各 8只 )对照。结果 :脾虚 Hp感染组大鼠胃粘膜 Hp定植量显著增加 ,炎症程度随之加重 (P <0 .0 1) ;脾虚组胃粘膜炎症程度差异无显著性意义 (P >0 .0 5 )。结论 :脾胃虚弱可能是 Hp感染的病理基础 ,脾虚感染 Hp蒙古沙土鼠动物模型的建立对研究 Hp感染的中医致病机制 ,评价中药治疗 Hp的疗效 ,具有重要的应用价值。     

Overexpression of c-fos in Helicobacter pylori-induced gastric precancerosis of Mongolian gerbil

AIM: To explore dysregulation of c-fos in several human malignancies, and to further investigate the role of c-fos in Helicobacter pylori ( H. pylori)-induced gastric precancerosis.METHODS: Four-week-old male Mongolian gerbils were H. pyloriNCTC 11 637 in Brucella broth were inoculated orally into 20 Mongolian gerbils. Another 20 gerbils were inoculated with Brucella broth as controls. 10 of the infected gerbils and 10 of the non- infected control gerbils were sacrificed at 25 and 45 weeks after infection. The stomach of each gerbil was removed and opened for macroscopic observation. The expression of c-fos was analyzed by RTPCR and immunohistochemical studies in H. pylori-induced gastric precancerosis of Mongolian gerbil. Half of each gastric antrum mucosa was dissected for RNA isolation and RTPCR. β-actin was used as the housekeeping gene and amplified with c-fos as contrast. PCR products of c-fos were analyzed by gel image system and the level of c-fos was reflected with the ratio of c-fos/β-actin. The immunostaining for c-foswas conducted using monoclonal antibody of c-fosand the StreptAvidin-Biotin-enzyme Complex kit.RESULTS: H. pyloriwas constantly found in all infected animals in this study. After infection of H. Pylorifor 25 weeks,ulcers were observed in the antral and the body of stomach of 60 % infected animals (6/10). Histological examination showed that all animals developed severe inflammation, especially in the area close to ulcers, and multifocal lymphoid follicles appeared in the lamina propria and submucosa. After infection of H. Pylorifor 45 weeks, severe atrophic gastritis in all infected animals, intestinal metaplasia in 80 % infected animals (8/10) and dysplasia in 60 % infected animals (6/10) could be observed. C-fos mRNA levels were significantlyhigher after infection of H. pylorifor 25 weeks (1.84±0.79),and for 45 weeks (1.59±0.37) than those in control-animals (0.74±0.22, P＜0.01). C-fos mRNA levels were increased 2.5-fold by 25th week (P＜0.01) and 2.1-fold by 45th week (P＜0.01) in precancerosis induced by H. pylori, when compared with normal gastric epithelium of Mongolian gerbil. Immunohistochemical staining revealed exclusive nuclear staining of c-fos. Furthermore, there was a sequential increase in c-fos positive cells from normal epithelium to precancerosis.CONCLUSION: The study suggested that overexpression of c-fos occurs relatively early in gastric tumorigenesis in this precancerosis model induced by H, pylori.