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。     

幽门螺杆菌感染Balb/c 小鼠模型的建立及对N-甲基-N-亚硝基脲诱发胃癌的影响

目的建立一种稳定的造模周期短的幽门螺杆菌(Hp)感染模型,观察Hp对小鼠胃黏膜的损害程度,同时研究Hp感染是否促进亚硝基类化合物的致癌作用.方法 94只Balb/c小鼠分为4组.第1组单用N-甲基-N-亚硝基脲(MNU);第2、3组小鼠用灌胃法定植Hp,第3组小鼠加用MNU灌胃;第4组为正常对照.36周后处死全部小鼠,分别用尿素酶、Giemsa染色和微需氧细菌培养检测Hp定植;H-E染色进行鼠胃黏膜病理诊断.结果 Balb/c小鼠Hp定植率达93.9%.Hp单一处理组中度以上炎症占100.0%,其中萎缩性胃炎占20.0%;而Hp和MNU联合处理组中度以上炎症占100.0%,其中萎缩性胃炎占23.1%,不典型增生占42.3%和57.7%(胃体和胃窦),并发现2只小鼠有低分化腺癌,占7.1%.Hp处理组和Hp MNU联合处理组在炎症程度上与正常对照组相比,差异有统计学意义(P＜0.01).结论本实验成功建立了Hp感染小鼠模型,验证了Hp和胃癌的发生有高度相关性,证实Hp在协同MNU致癌性中的作用,提示胃癌的发生并非Hp感染单一因素的结果,而和多因素共同作用有关.     

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     

Gastric expression of inducible nitric oxide synthase and myeloperoxidase in relation to nitrotyrosine in Helicobacter pylori-infected Mongolian gerbils

Objective. For obscure reasons Helicobacter pylori infection of the gastric mucosa is maintained despite a pronounced host defence response. The present study elucidates possible H. pylori-related interference in the oxy- and nitro-radical formation pathways. Material and methods. Male Mongolian gerbils were infected with two different H. pylori strains, TN2GF4 and SS1. At 3, 6, 12 or 18 months after inoculation, gastric expressions of myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS) and nitrotyrosine were assessed by Western blotting. Results. Expression of both iNOS and MPO was markedly up-regulated in the H. pylori-infected animals compared with non-infected controls. The TN2GF4-infected animals initially (at 3 and 6 months) demonstrated pronounced expression of both iNOS and MPO. The SSI-infected animals exhibited a slower onset with significantly increased iNOS after 12 and 18 months. Nitrotyrosine expression was slightly elevated in the infected groups at 3 and 6 months compared with that in the controls. Nitrotyrosine levels then decreased and were no longer significantly different from those of controls (TN2GF4-infected animals) or were lower (SS1-infected animals) than in the controls. Conclusions. The results indicate that peroxynitrite formation as reflected by nitrotyrosine expression is low or even inhibited in chronic H. pylori infection despite pronounced expression of enzymes representing both the oxy- and nitro-radical formation pathways. The results support the theory that H. pylori survival is related to functional inhibition of mucosal enzymatic NO and/or oxy-radical formation.     

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。     

Quantitative measurement of nitric oxide and hydrogen peroxide in Helicobacter pylori-infected Mongolian gerbils in vivo

Objective. Peroxynitrite formation, as reflected by nitrotyrosine expression, is low in Helicobacter pylori-infected Mongolian gerbils despite pronounced expression of radical-forming enzymes. The aim of the present study was to investigate in vivo whether H. pylori inhibits either one or both of the nitro- and oxyradical formation pathways. Material and methods. Male Mongolian gerbils were infected with two different H. pylori strains, TN2GF4 and SS1. Six months after inoculation, direct measurement of NO and H₂O₂ was performed in vivo using electrochemical microsensors positioned in close proximity to the gastric mucosa. Results. In the TN2GF4-infected animals the level of NO was significantly lower than that in controls. No significant difference in NO levels was detected between the SS1-infected group and the controls. H₂O₂ was significantly increased in the SS1 animals compared with that in controls after 6 months. The H₂O₂ level in the TN2GF4 group did not differ from that in controls. Conclusions. The results indicate that H. pylori infection is associated with strain-dependent functional inhibition of both the NO and oxyradical formation pathways in the gastric mucosa.     

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.     

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.     

DEC205在幽门螺杆菌感染的胃黏膜中的表达

目的:探讨幽门螺杆菌(Helicobacter pylori,H.pylori)感染的胃黏膜与DEC205的关系.方法:对13名H.pylori感染阳性患者的胃黏膜进行内窥镜活检,以及对这13例中7例被根除H.pylori的患者的胃黏膜进行二次内窥镜活检,活检标本行冰冻组织切片后,分别进行DEC205抗体的免疫组织化学染色,以及进行DEC205抗体和CD14抗体的免疫荧光染色.结果:对比除菌成功H.pylori阴性的患者,H.pylori阳性患者胃小凹处的胃黏膜上皮细胞间DEC205的表达明显增多.胃黏膜中,DEC205与CD14表达在同一个位置,而且DEC205与CD14的表达在H.pylori感染胃黏膜中明显高于除菌成功的H.pylori阴性的患者.结论:胞吞受体DEC205在H.pylori感染的胃黏膜巨噬细胞中呈高表达.     

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     

Short-term Celecoxib intervention is a safe and effective chemopreventive for gastric carcinogenesis based on a Mongolian gerbil model

AIM: To evaluate the optimal intervention point of a selective cyclooxygenase-2 (COX-2) inhibitor, Celecoxib, for inhibiting Helicobacter pylori ( H pylori)-associated gastric carcinogenesis in Mongolian gerbils (MGs).METHODS: One hundred and twelve MGs were divided into six groups (A-F). One hundred gerbils were inoculated with H pylori (groups A-E). Twelve gerbils were inoculated with vehicle broth only (group F). After 4 wk, they were given N'-methyl-N'-nitro-N-nitroso-guanidine (MNNG) (50 mg/mL) in the drinking water for 20 wk. In groups B-E, the animals were given the stock Celecoxib (10 mg/kg per day) diet from the 21st, 31st, 21st and 41st week respectively. The periods of administering Celecoxib were 30, 20, 20, and 15 wk respectively. On the 51st week, the animals were sacrificed for histological examination. Local PCNA expression was examined by the immunohistochemistry method. The expression of COX-2 protein was assessed by Western Blot. Analysisused the χ~2 test. The difference was regarded as significant when P value was less than 0.05. RESULTS: Seventeen percent (17/100) of H pyloriinfected MGs developed gastric cancer. All of these lesions were well-differentiated adenocarcinoma. The incidence rates of adenocarcinoma in groups A-F were 40%, 0%, 0%, 20%, 25%, and 0% respectively. The inflammatory scores were higher in group B than in other groups. There was no inflammatory response noted in group F. Celecoxib treatment resulted in a significant reduction in the proliferation of H pyloriinfected mucosal cells (groups B, C and D) ( P < 0.01). The expression of COX-2 protein was significantly attenuated in the groups which were Celecoxib-treated for more than 20 wk (groups B, C, D). The groups treated with Celecoxib had a significantly lower rate of advanced gastric cancer (34% vs 75%, P < 0.001) There were no sudden deaths in any of the groups.CONCLUSION: Short-term treatment with Celecoxib has an anti-carcinogenic effect, and resulted in less severe inflammation and inhibited the invasive degree of gastric cancer.     

胃癌实验模型建立的研究现况

胃癌死亡率居全球恶性肿瘤第二位,占癌症总死亡率的9.7%.胃癌的发生是多步骤、多因素的,诸如致病细菌、宿主遗传因素和免疫应答等.动物模型在研究胃癌生物学行为和临床诊治过程中占有重要地位.本文将分别从微生物原位诱发、化学致癌剂原位诱发、癌细胞定植、转基因模型和计算机模拟五方面重点阐述胃腺癌模型建立的现况.     

Th17、IL-17在幽门螺杆菌相关性胃癌中的研究进展

辅助性T细胞17(T helper cell17,Th17)是一种新发现的CD4+T细胞亚型,他以分泌白介素17(interleukin 17,IL-17)和表达转录因子RORγ为特征,在机体各种肿瘤和感染性疾病中起着重要作用.胃癌是一种与慢性幽门螺杆菌(Helicobacter pylori,H.pylori)感染密切相关的恶性肿瘤,死亡率极高.研究发现,Th17及其分泌的IL-17在H.pylori感染所致的慢性萎缩性胃炎、胃溃疡、不典型增生、肠上皮化生及胃癌的发生、发展中起着不可忽视的作用,相关研究为胃癌的早期诊断、个性化防治、瘤苗开发和预后评价提供了新思路.     

幽门螺杆菌感染动物模型菌株及其研究进展

幽门螺杆菌（Helicobacter pylori,Hp）菌株间基因水平的差异明显,因此在动物实验中,菌株的选择也是决定实验结果的重要方面。目前,动物模型中使用的菌株主要有Hp外的螺杆菌属其他菌株、临床分离株及幽门螺杆菌小动物适应株。这些菌株用于模拟Hp感染人后的病程,以便进行致病机制的研究和治疗效果的评价。本文就建立动物模型过程中使用的主要螺杆菌株及其适应范围作一综述。     

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...     

Increased expression of tyrosine phosphatase SHP-2 in Helicobacter pylori-infected gastric cancer

AIM:To explore the alteration of tyrosine phosphatase SHP-2 protein expression in gastric cancer and to assess its prognostic values.METHODS:Three hundred and five consecutive cases of gastric cancer were enrolled into this study.SHP-2 expression was carried out in 305 gastric cancer specimens,of which 83 were paired adjacent normal gastric mucus samples,using a tissue microarray immunohistochemical method.Correlations were analyzed between expression levels of SHP-2 protein and tumor parameters or clinical outcomes.Serum anti-Helicobacter pylori(H.pylori) immunoglobulin G was detected with enzyme-linked immunosorbent assay.Cox proportional hazards model was used to evaluate prognostic values by compassion of the expression levels of SHP-2 and disease-specific survivals in patients.RESULTS:SHP-2 staining was found diffuse mainly in the cytoplasm and the weak staining was also observed in the nucleus in gastric mucosa cells.Thirty-two point five percent of normal epithelial specimen and 62.6% of gastric cancer specimen were identified to stain with SHP-2 antibody positively(P < 0.001).Though SHP-2 staining intensities were stronger in the H.pylori(+) group than in the H.pylori(-) group,no statistically significant difference was found in the expression levels of SHP-2 between H.pylori(+) and H.pylori(-) gastric cancer(P = 0.40).The SHP-2 expression in gastric cancer was not significantly associated with cancer stages,lymph node metastases,and distant metastasis of the tumors(P = 0.34,P = 0.17,P = 0.52).Multivariate analysis demonstrated no correlation between SHP-2 expression and disease-free survival(P = 0.86).CONCLUSION:Increased expression of SHP-2 protein in gastric cancer specimen suggesting the aberrant upregulation of SHP-2 protein might play an important role in the gastric carcinogenesis.     

Latest insights into the effects of Helicobacter pylori infection on gastric carcinogenesis

There appears to be the strong association between Helicobacter pylori (H pylori) and gastric cancer. We reviewed the latest evidences about the effects of H pylori infection on gastric carcinogenesis, classified into epidemiology, dynamics of gastric mucosal changes, DNA damages, virulence factors, host factors, and source of gastric malignancy. Through the considerable progress made in research into virulence factors resulting from differences between H pylori strains, such as cagA positivity, as well as into host factors, such as gene polymorphisms, a diverse spectrum of H pylori-associated diseases, including gastric cancer, is beginning to lend itself to elucidation. The impact of the novel hypothesis advanced by Houghton et al proposing bone-marrow derived stem cells (BMDC) as a potential source of gastric malignancy on evolving research remains to be seen with interest. Further progress in research into H pylori eradication as a viable prophylaxis of gastric cancer, as well as into the mechanisms of gastric carcinogenesis, is to be eagerly awaited for the current year and beyond.     

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。