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。     

Long-term effects of Helicobacter pylori eradication in Mongolian gerbils

Background: In this study, to clarify whether Helicobacter pylori eradication alters the course of the development of gastric mucosal changes in the stomach, we examined the long-term effects of H. pylori eradication on H. pylori-inoculated gerbils. Methods: A total of 40 H. pylori-inoculated gerbils were randomized and subjected, at 22 months after inoculation, to eradication treatment with dual therapy of omeprazole plus clarithromycin, or with therapy with a novel quinolone compound, Y-34867, alone. The animals were killed at the start of administration (control group) or at 8 months after the completion of therapy (vehicle or eradication-treatment groups). Results: Severe histopathological changes in the gastric mucosa were observed in all H. pylori-inoculated gerbils at the start of administration. At 8 months after completion of therapy, the frequency of gastritis, erosion, intestinal metaplasia, and gastric carcinoid in the eradication therapy groups was markedly reduced compared with that in the control and vehicle groups. Values for anti-H. pylori IgG titer, bacterial counts, and gastrin also decreased significantly. Conclusions: These results suggest that H. pylori eradication may have had a therapeutic effect not only on gastritis, erosion, and gastric ulcer but also on glandular atrophy, intestinal metaplasia, and gastric carcinoid. Received: November 8, 2001 / Accepted: May 31, 2002 Reprint requests to: F. Hirayama     

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.     

Helicobacter pylori strain-specific modulation of gastric inflammation in Mongolian gerbils

AIM: The cag pathogenicity island (PAI) is one of potential virulence determinants of Helicobacter pylori. The Mongolian gerbil is a suitable experimental animal for the screening of virulence factors of H pylori. METHODS: Five-week-old Mongolian gerbils were inoculated with a standard H pylori strain (ATCC 43504) possessing the cag PAI or a clinical isolate lacking the genes' cluster (OHPC-0002). The animals were killed at 2, 4, 8, 24 and 48 wk after inoculation (n=5 each), and macroscopic and histopathological findings in the stomachs were compared. RESULTS: In gerbils infected with ATCC 43504, a more severe degree of infiltration of polynuclear and mononuclear cells and lymphoid follicles was observed from 4 wk after inoculation compared to gerbils infected with OHPC-0002 especially in the antrum and transitional zone from the fundic to pyloric gland area. In addition, glandular atrophy, intestinal metaplasia, gastric ulcer and hyperplastic polyps were noted in gerbils infected with ATCC 43504, whereas only mild gastric erosions occurred in those infected with OHPC-0002. CONCLUSION: Our results indicate that the cag PAI could be directly involved in gastric immune and inflammatory responses in the Mongolian gerbils, leading to a more advanced gastric disease.     

蒙古沙土鼠不同幽门螺杆菌菌株感染相关性胃病的研究进展

幽门螺杆菌(Helicobacter pylori,H.pylori)感染在世界范围内高发,他定植于人胃黏膜,导致慢性胃炎及胃癌的发生.蒙古沙鼠(mongolian gerbil,MG)很少患自发性胃炎,且不是H.pylori 的自然宿主.人工接种H.pylori后,蒙古沙鼠患H.pylori相关性胃病与胃病患者最相似...     

幽门螺杆菌长期感染蒙古沙土鼠建立胃癌模型的研究

目的：幽门螺杆菌（Hp）长期感染蒙古沙土鼠（MGs)发生胃癌鲜见报道。本实验旨在研究Hp长期定植于MGs导致胃黏膜病变及其致癌性。方法：36只交封闭MGs（雌雄各半）分别接种Hp标准株ATCC43504，或从胃癌患者胃内分离的Hp161株，10只MGs作为对照，接种后第8、20、28和84周分别处死，检查细菌定植及胃黏膜病变情况。结果：绝大多数MGs胃内Hp持续定植，胃黏膜炎症随时间逐渐加重，第84周组织学特征是胃黏膜中－重度胃炎，以淋巴细胞为主的单核细胞弥漫性浸润，黏膜，黏膜下，甚至浆膜下有大量淋巴滤泡浸润，偶见淋巴上皮病变，萎缩，肠化较少见，上皮增生明显，24％（4／17）发生增生性息肉，第84周时18％（3／17）发生高分化腺癌（Hp161组1例，ATCC43504组2例；1雄2雌），结论：单独感染Hp能诱导MGs发生胃癌，并提示可利用不同种属的MGs和不同Hp菌株进行相关研究，首次报道了雌性MGs感染也可发生胃癌。     

蒙古沙鼠感染幽门螺杆菌后的胃部病理学变化研究

目的　建立幽门螺杆菌 (Helicobacterpylori,Hp)的蒙古沙鼠长期感染模型并观察其胃内的病理学改变。 方法　蒙古沙鼠 (8周龄 ) 80只 ,随机分为实验组 (40只 )和对照组 (40只 ) ,所有沙鼠禁食水 1d ,第 2天灌喂 5 0 %的乙醇 0 3ml,试验组第 3天及第 4天分 3次灌喂cagA Hp菌液 (10 9cfu/ml) ,0 5ml/只·次 ,对照组灌喂相同量无菌肉汤。最后一次灌喂后 2h进食水。距最后一次灌菌后 4、8、12、2 0、2 4周分别剖杀动物 ,每次实验组、对照组各 8只 ,进行微生物学检查 (粘膜涂片染色镜检、分离培养、快速尿素酶试验 )、血清学检查 (ELISA测抗Hp抗体 )和病理学检查。结果　实验组沙鼠在不同时间Hp感染率均达到 10 0 %。从第 4周开始 ,可见所有实验组沙鼠胃组织中有大量炎性细胞浸润 ,随着时间推移形成淋巴滤泡。部分沙鼠在第 12周后至 2 4周可见明显出血、慢性活动性胃炎及溃疡 ,有的溃疡可深达肌层。对照组沙鼠均无Hp定植及组织学病变。结论　蒙古沙鼠感染Hp后 ,可出现与人极相似的病理组织学改变 ,对于研究Hp的致病机制及疫苗具有重要价值     

Effects of Helicobacter pylori infection on gastric acid secretion and serum gastrin levels in Mongolian gerbils

BACKGROUND AND AIMS: Body gastritis caused by Helicobacter pylori infection appears to inhibit gastric acid secretion. The aim of this study was to determine the effects of H pylori infection on gastric acid secretion and clarify its mechanisms with reference to interleukin 1beta (IL-1beta). METHODS: (1) Mongolian gerbils were inoculated orally with H pylori. Before, six, and 12 weeks after inoculation, serum gastrin levels, gastric acid output, and IL-1beta mRNA levels in the gastric mucosa were determined. Pathological changes were also determined according to the updated Sydney system. (2) Effects of recombinant human IL-1 receptor antagonist (rhIL-1ra) on gastric acid output and serum gastrin levels were also determined. RESULTS: (1) Scores for activity and inflammation of gastritis and serum gastrin levels were significantly increased, and gastric acid output was significantly decreased six and 12 weeks after inoculation with H pylori. IL-1beta mRNA levels in the gastric mucosa were also elevated six and 12 weeks after inoculation with H pylori. (2) Acid output and serum gastrin levels in the infected groups returned to control levels after rhIL-1ra injection. CONCLUSIONS: Gastric acid secretion is decreased and serum gastrin levels are increased in Mongolian gerbils infected with H pylori. This change in gastric acid secretion appears to be mediated by IL-1beta induced by H pylori infection.     

13C-尿素呼气试验在蒙古沙鼠幽门螺杆菌感染检测中的应用

目的　应用13 C -尿素呼气试验检测蒙古沙鼠幽门螺杆菌感染 ,从而建立一长期监控小型试验动物幽门螺杆菌感染无创检测技术。方法　分别在蒙古沙鼠感染幽门螺杆菌后第 2 0 ,5 0 ,10 0及 2 0 0d用13 C -尿素呼气试验进行检测 ,并对检测后沙鼠以细菌分离培养、ELISA、PCR、快速尿素酶试验、病理切片等五种常规方法检测幽门螺杆菌。结果　在上述不同检测时期 ,用13 C -尿素呼气试验所得蒙古沙鼠幽门螺杆菌感染阳性率分别为 77 78% ,83 33% ,84 2 1%和 80 0 0 % ,而应用常规方法检测结果阳性率为 83 33% ,88 88% ,94 2 1%和 85 0 0 %。比较两组试验结果发现 ,13 C -尿素呼气试验比常规检测方法检出阳性率相对偏低 ,但统计学分析发现其具有一致性。结论　13 C -尿素呼气试验用于幽门螺杆菌感染蒙古沙鼠模型检测是一种可行的无创检测方法 ,可作为评价Hp感染的重要参考指标之一     

H pylori infection causes chronic pancreatitis in Mongolian gerbils

AIM： To investigate whether chronic H pylori infection has the potential to induce pancreatitis in the Mongolian gerbil model, and whether it is dependent on an intact type Ⅳ secretion system. METHODS： Mongolian gerbils were infected with wild type （WT） H pylori type Ⅰ strain B128 or its isogenic mutant B128 △cag γ （defective type Ⅳ secretion）. After seven months of infection, H pylori was reisolated from antrum and corpus and Hpylori DNA was analyzed by seminested polymerase chain reaction （PCR）. Inflammation and histological changes were documented in the gastric antrum, corpus, and pancreas by immunohistochemistry. Cytokine mRNA, gastric pH, plasma gastrin, amylase, lipase, and glucose levels were determined.
RESULTS： The H pylori infection rate was 95%. Eight infected animals, but none of the uninfected group, developed transmural inflammation and chronic pancreatitis. Extensive interstitial fibrosis and inflammation of the pancreatic lobe adjacent to the antrum was confirmed by trichrome stain, and immuno-histochemically. Pro-inflammatory cytokine mRNA was significantly increased in the antral mucosa of all infected gerbils. In the corpus, only cytokine levels of WT-infected animals andthose developing transmural inflammation and pancreatitis were significantly increased. Levels of lipase, but not glucose or amylase levels, were significantly reduced in the pancreatitis group. H pylori DNA was detected in infected antral and corpus tissue,but not in the pancreas
CONCLUSION： H pylori infection is able to induce chronic pancreatitis in Mongolian gerbils independently of the type Ⅳ secretion system, probably by an indirect mechanism associated with a penetrating ulcer.     

Anti-Helicobacter pylori therapy significantly reduces Helicobacter pylori -induced gastric mucosal damage in Mongolian gerbils

AIM: To investigate the effectiveness of 4 d‘anti-Helicobacter pyloritherapy on the H pylori-infected Mongolian gerbils based on physiological and pathological changes. METHODS: We used 6-wk-old male gerbils orally inoculated with H pylori (ATCC43504, 2×10^8 CFU/mL). Seven weeks alter Hpyloriinoculation, the animals of study group received 4 d‘arti-H pyloritriple therapy (Hpylorieradicated group). Seven days later, all animals of the H pylori-eradicated and control groups (H pylori-infected & H pylori-uninfected groups) were sacrificed. We examined gastric mucosal lesions macroscopically, studied gastritis microscopically and determined the stomach weight ratio, myeloperoxidase (MPO) activity and prostaglandin (PG) E2 level. RESULTS: The results showed that both macroscopic and histological gastric damages were significantly less in H pylori-eradicated group than H pylori-infected group. Stomach weight ratio, MPO activity and PGE2 levels were significantly higher in H pylori-infected group than those in the other two groups. CONCLUSION: Four days‘anti-H pylori therapy was effective in the improvement of H pylori-induced gastric lesions in Mongolian gerbils.     

Association of Helicobacter pylori infection with atrophic gastritis and intestinal metaplasia

AIMS: To evaluate the effect of Helicobacter pylori infection and aging on atrophy and intestinal metaplasia of the gastric mucosa. METHODS: One hundred and sixty-three patients were divided into three age groups and underwent an upper gastrointestinal endoscopy where no esophagitis, peptic ulcers, or malignancies were detected. Two biopsy specimens were obtained from the anterior and posterior walls of the antrum and of the fundus. These were used to evaluate the grade of gastritis, bacterial culture and histologic evidence of H. pylori infection. RESULTS: Helicobacter pylori infection was found to be directly associated with an increased risk of gastritis grade (odds ratio (OR) = 90 (95% CI; 30-270)). An age of 60 years and older along with H. pylori infection was also strongly associated with an increased risk of atrophy (OR = 6.6, (95% CI; 2.9-15.2)); OR = 9.8, (95% CI; 2.7-35.4)), as was intestinal metaplasia of the gastric mucosa (OR = 5.5, (95% CI; 1.7-17.6)); OR = 7.9, (95% CI; 2.8-46.1)). The prevalence of atrophic gastritis increased with advancing age in H. pylori-infected patients, but no such phenomenon was observed in H. pylori-uninfected patients. The prevalence of intestinal metaplasia significantly increased with advancing age, irrespective of the presence of H. pylori infection. In addition, H. pylori uninfected female patients had a decreased risk of intestinal metaplasia. CONCLUSIONS: These results suggest that atrophic gastritis is not a normal aging process, but instead is likely to be the result of H. pylori infection, while intestinal metaplasia is caused by both the aging process and H. pylori infection. A decreased risk of intestinal metaplasia found in uninfected female subjects may partly explain the lower prevalence of gastric cancer in females than in males.     

Biopsy site for detecting Helicobacter pylori infection in patients with gastric cancer

Background:  Helicobacter pylori eradication is recommended in post-gastric cancer resection, but premalignant changes may prevent the detection of H. pylori . The aim of this study was to determine appropriate biopsy site for detecting H. pylori in gastric cancer patients.
Materials and Methods:  Consecutive patients (194) with gastric adenocarcinoma were prospectively enrolled. Helicobacter pylori was evaluated by serology, histology and rapid urease test. Biopsy sites included antrum lesser curvature, upper body lesser curvature (UBLC) and upper body greater curvature (UBGC). Two biopsy specimens were obtained from each site for histological examination. One additional specimen was obtained from UBGC for the rapid urease test.
Results:  The overall infection rate of H. pylori was 84.0% (95% CI 78.9–89.2). The sensitivity of histology for detecting H. pylori at various sites was: antrum (54.9%; 95% CI 45.7–63.9), UBLC (80.3%; 95% CI 72.2–87.0) and UBGC (95.1%; 95% CI 89.6–98.2). Specificities of all three biopsy sites were more than 95%. Sensitivity and specificity of the rapid urease test performed at UBGC were 96% and 100%, respectively. Sensitivities of histology decreased in correlation with increasing severity of atrophy and intestinal metaplasia (both P  < 0.001 using the chi-square test for trend). The proportions of moderate to marked atrophy/intestinal metaplasia at UBGC (12.8%/14.7%) were significantly lower than those at antrum (50.0%/57.8%, P  < 0.001 respectively) or UBLC (40.0%/48.9%, P  < 0.001 respectively).
Conclusions:  The UBGC side is the most sensitive and specific biopsy site to detect H. pylori in gastric cancer patients due to less frequent atrophy and intestinal metaplasia than at the antrum or UBLC side.     

Evaluation of combined antibiotic-omeprazole therapies in Helicobacter pylori-infected Mongolian gerbils

Mongolian gerbils are a laboratory host for gastric colonization with Helicobacter pylori, showing gastritis followed by typical gastric ulcer after infection with H. pylori. In such gerbils, we evaluated combined therapies of amoxicillin (AMPC) and clarithromycin (CAM) as antibiotics, and omeprazole (OPZ) as a H⁺/K⁺ adenosine triphosphatase (ATPase) inhibitor. The gerbils were orally inoculated with 2 × 10⁸ bacilli of ^{H. pylori} ATCC 43504. Four weeks after inoculation, the infected gerbils were orally treated singly with OPZ, AMPC, and CAM, and their insufficient efficacy on bacterial clearance was confirmed by a polymerase chain reaction technique, and by a culture method. In contrast, combined therapy of OPZ plus either AMPC or CAM showed significant bacterial clearance, demonstrating the efficacy of this combined therapy in the gerbil model. Mongolian gerbils are suggested to be useful for the pharmacological evaluation of anti-H. pylori compounds. Received Mar. 11, 1997; accepted June 27, 1997     

Anti-Helicobacter pylori therapy significantly reduces Helicobacter py/ori-Induced gastric mucosal damage in Mongolian gerbils

AIM: To investigate the effectiveness of 4 d' anti-Helicobacter pylori therapy on the H pylori-infected Mongolian gerbils based on physiological and pathological changes. METHODS: We used 6-wk-old male gerbils orally inoculated with H pylori (ATCC43504, 2×108 CFU/mL). Seven weeks after H pylori inoculation, the animals of study group received 4 d' anti-H pylori triple therapy (H pylori-eradicated group). Seven days later, all animals of the H pylori-eradicated and control groups (H pylori-infected & H pylori-uninfected groups) were sacrificed. We examined gastric mucosal lesions macroscopically, studied gastritis microscopically and determined the stomach weight ratio, myeloperoxidase (MPO) activity and prostaglandin (PG) E2 level. RESULTS: The results showed that both macroscopic and histological gastric damages were significantly less in H pylori-eradicated group than H pylori-infected group. Stomach weight ratio, MPO activity and PGE2 levels were significantly higher in H pylori-infected group than those in the other two groups. CONCLUSION: Four days' anti-H pylori therapy was effective in the improvement of H pylori-induced gastric lesions in Mongolian gerbils.