硫氧还蛋白-1高表达的幽门螺杆菌慢性感染蒙古沙土鼠模型的建立与评价

Evaluation and establishment of Mongolian gerbil model of long-term infection of Helicobacter pylori with highly-expressed thioredoxin-1 gene

目的:建立硫氧还蛋白-1(thioredoxin-1,Trx1)基因高表达的幽门螺杆菌(Helicobacter pylori,Hp)慢性感染蒙古沙土鼠模型,评价Trx1在Hp长期定植导致胃黏膜的病变及其致癌性中的作用。方法:健康雄性蒙古沙土鼠75只,随机分为3组:Trx1高表达Hp组(30只),Trx1低表达Hp组(30只)和对照组(15只)。分别采用Trx1高表达和低表达Hp菌株灌胃,建立Hp长期感染蒙古沙土鼠腺胃模型。在接种Hp后第4、20、34、48、70和90周分批处死动物,行快速尿素酶实验和Warthin-Starry银染判定Hp定植情况,HE染色观察胃黏膜病理改变。结果:(1)成功建立了Trx1高表达和低表达Hp长期感染蒙古沙土鼠腺胃的动物模型。(2)Trx1高表达和低表达Hp组胃黏膜病变随时间延长而逐渐加重,Trx1高表达Hp组出现黏膜不平及结节性病变的时间分别为第20周和第34周,早于Trx1低表达Hp组(分别为第48周和第70周);Trx1高表达Hp组从第48周起观察到黏膜糜烂(3只),而Trx1低表达Hp组和对照组在整个实验过程中均未见明显的黏膜糜烂改变。Trx1高表达Hp组出现病变的时间和病变范围明显早于/重于Trx1低表达Hp组。(3)Trx1高表达Hp组在接种后第34周可观察到上皮细胞的轻度异型增生,明显早于Trx1低表达Hp组(第48周)。第90周,Trx1高表达Hp组有71.4%(5/7)、Trx1低表达Hp组有42.8%(3/7)检出管状腺癌(P=0.592),均为早期癌,且Trx1高表达Hp组有1例为黏膜下癌,此外,Trx1高表达Hp组还观察到2例上皮细胞重度异型增生(28.6%,2/7),而在Trx1低表达Hp组仅观察到3例上皮细胞中度异型增生(42.8%,3/7)。结论:Trx1高表达和低表达的Hp可稳定定植于蒙古沙土鼠腺胃,出现类似于人感染Hp后出现的各种病理变化,并诱发腺癌的发生;Trx1高表达Hp组胃黏膜病变明显重于Trx1低表达Hp组,Trx1可能是我国人群Hp致病及致癌的毒力因子。

Objective： To establish a Mongolian gerbils model by long-term infection of Helicobacter pylori（ Hp） with highly-expressed thioredoxin-1（ Trx1） gene and to investigate the histopathological findings of gastric mucosa in Mongolian gerbils. Methods： In this study,75 healthy male Mongolian gerbils were randomly divided into 3 groups： Hp with highly-expressed Trx1 gene group（ n = 30）,Hp with lowly-expressed Trx1 gene group（ n = 30）,and control group（ n = 15）. The animals underwent gastric perfusion of Hp suspension once a week for 5 weeks. The animals were sacrificed at the end of 4,20,34,48,70,and 90 weeks after inoculation for detecting Hp colonization by rapid urease test and Warthin-Starry silver staining and histological examination,respectively. Results：（ 1） The Mongolian gerbil model of long-term infection of Hp with highly-expressed Trx1 gene and lowly-expressed Trx1 gene were successfully established.（ 2） The macroscopic mucosal lesions,including erythema,uneven,erosion,nodules,etc. could be observed in experimental groups. The severity of lesions and the time when lesions occurred in Hp with highly-expressed Trx1 gene group were heavier / earlier than that in Hp with lowly-expressed Trx1 gene group.（ 3） Histopathologically,the gastric mucosa of Hp with highly-expressed Trx1 gene group showed the mild dysplastic hyperplasia of epithelial cells 34 weeks after the Hp inoculation,and the time was in the 48 th week in Hp with lowly-expressed Trx1 gene group. At the end of the 90 th week after Hp inoculation,the gastric adenocarcinoma could be detected in the two experimental groups（ 71. 4% vs. 42. 8%）. The difference between the two experimental groups did not reach statistical significance（ P = 0. 592）,which might be due to the small sample capacity and / or short observation time.In addition,there were 2 cases with severe epithelial dysplastic hyperplasia in Hp with highly-expressed Trx1 gene group,and only 3 cases with moderate epithelial dysplastic hyperplasia in Hp with lowly-expressed Trx1 gene group. The uninfected control animals showed no abnormal findings throughout the entire observation period. Conclusion： Hp with highly-expressed / lowly-expressed Trx1 gene colonizes stably in the glandular gastric mucosa of Mongolian gerbils. The histological changes after infection are similar to those of the Hp infected human being,and Hp with highly-expressed Trx1 gene cause the injury of gastric mucosa and the occurrence of gastric adenocarcinoma. Trx1 maybe the virulence factor that participates in the pathogenesis of gastric cancer and Hp expressing high levels of Trx1 should be highly toxic for gastric diseases in China.