幽门螺杆菌感染小鼠慢性胃炎模型的建立及评价

Establishment and evaluation of a mouse model of chronic gastritis induced by Helicobacter pylori

目的建立幽门螺杆菌(H.pylori)感染动物模型,评价H.pylori相关慢性胃炎胃黏膜病理变化。方法灌胃H.pylori SS1菌株建立在体感染,感染后第2周后采用快速尿素酶法和PCR法检测感染成功率;确认感染成功后再分别继续饲养至6周和12周,建立H.pylori相关慢性胃炎动物模型。实验结束后,取胃腺体组织别进行HE和硼酸美兰染色,分析胃炎程度及H.pylori感染程度;生化法检测胃组织中髓过氧化物酶(myeloperoxidase,MPO),超氧化物歧化酶(superoxide dismutase,SOD),丙二醛(malondialdehyde,MDA)和过氧化氢酶(catalase,CAT)的含量变化;RT-q PCR法检测胃组织中COX-2、iNOS、TNF-α和IL-1β基因表达的变化。结果与正常组相比,模型6周和12周组胃组织内可见H.pylori定植,并且黏膜层有不同程度的慢性炎性细胞浸润,腺体萎缩和肠化生情况;同时组织中CAT和SOD的含量明显下降,MPO和MDA的水平和COX-2、iNOS、TNF-α和IL-1β基因表达均有显著上升(P<0.05或P<0.01)。结论通过灌胃给菌的方法可以成功将H.pylori定植于小鼠体内,并在定植的6周和12周后均可引起慢性炎性细胞的浸润,并使增强胃腺体组织内氧化应激水平和促炎基因的表达,但12周模型感染程度更深,出现腺体萎缩和肠化生的情况。

Objective To establish a mouse model of H. pylori infection, and to evaluate the chronic pathological changes in the gastric mucosa associated with H. pylori infection. Methods 34 male 5 -6-week old SPF C57BL/6 mice were used in this study. The mice were intragastrically administrated with a suspension of H. pylori SSI strain. Two weeks after infection, rapid urease test and PCR were performed to confirm the H. pylori infection. Successfully infected mice were randomly divided into 3 groups including the control group, 6-week and 12-week infected groups. Samples of gastric mucosa were taken for pathological analysis using HE and borax methylene blue staining. The contents of myeloperoxidase （MPO） , superoxide dismutase （SOD） , malondialdehyde （MDA） and catalase （CAT） in the gastric tissues were detected by biochemistry, and the expression levels of COX-2, iNOS, TNF-α and 1L-1β were examined by RT-qPCR. Results Compared with the control group, H. pylori colonization was observed in the gastric mucosa of the 6-week and 12-week infected mice, with chronic inflammatory cell infiltration, glandular atrophy and intestinal metaplasia to varying extents. The contents of CAT and SOD were significantly decreased, while the levels of MPO and malonaldehyde MDA, and the expression levels of COX-2, iNOS, TNF-α and IL-1β were significantly increased （ P 〈 0.05 or P 〈 0. 01 ）. Conclusions Intragastric administration with H. pylori in C57BL/6 mice can be successfully used to generate the bacterial colonization, leading to chronic inflammatory cell infiltration, enhanced oxidative stress, and up-regulated expression of proinflammatory genes in the gastric glandular tissues at 6 and 12 weeks after inoculation. However, the inflammatory changes are more extensive in the mice at 12 weeks after infection, with glandular atrophy and intestinal metaplasia.