幽门螺杆菌致肝脏病变的动物实验观察

Experimental study on the pathological effect of Helicobacter pylori on liver tissues

目的观察经口接种的幽门螺杆菌(Hp)能否到达肝脏,并作为独立的致病因素能否导致小鼠肝脏病变。方法Hp悉尼株经口接种C57BL/6小鼠,8个月时处死,观察小鼠肝组织细菌定植与病理变化,提取肝组织DNA,巢式聚合酶链反应(PCR)扩增Hp基因,16S rRNA PCR产物测序与胃黏膜培养Hp、接种Hp SS1 PCR产物同源比较。结果实验组15只小鼠肝组织6只基因阳性。肝组织扩增Hp 16SrRNA PCR产物测序分析结果显示与胃黏膜分离培养细菌、接种细菌同源性100%。4只肝脏观察到Hp,主要分布在中央静脉与肝血窦内;3只小鼠肝脏观察到以淋巴细胞为主的炎症浸润,部分肝细胞出现气球样变。结论经口接种的Hp可到达小鼠肝脏,能作为独立的致病因素引起肝脏炎症反应,其到达肝脏可能有血行和(或)胆道逆行两种途径。

Objective To observe whether H. pylori inoculated by oral route could arrive in livers and cause liver inflammation as an independent etiological factor. Methods C57BL/6 mice were orally inoculated with H. pylori SS1 strains and fed for 8 months. H. pylori colonization and pathologic consequences were studied in the liver and gallbladder tissues of the mice; the blood, liver tissue and gastric mucosa were obtained and cultured for H. pylori growth; The bacterial DNA extracted from the liver, bile and blood was examined by nested PCR for H. pylori genes. 16S rRNA PCR amplicons were sequenced and compared with the sequencing results of 16S rRNA PCR amphcons of the bacteria cultured from gastric mucosa and the inoculated H. pylori SS 1. Results The bacterial DNA extracted from the liver, bile and blood of the infected mice was detected for H. pylori genes by nested PCR. Six of the 15 samples were positive （40%） in the liver, 6 of 10 samples in the bile （60%）, and 2 of 10 samples in the blood （20%）. Sequencing results of 16S rRNA PCR products of the livers showed 100% homogeneity when compared with the cultured H. pylori from gastric mucosa and inoculated H. pylori SS1. H. pylori was found in 4 liver tissues of the 15 infected mice （26.7%） and 6 in the gallbladders （40%）. Infiltrations of lymphocyte cells along hepatic sinusoids and a lower degree infiltration around interlobular arteries and veins were observed; ballooning degeneration was also observed in some hepatocytes. Conclusion H. pylori inoculated by oral route could arrive in the liver and cause inflammation as an independent etiological factor. The routes which the microorganisms took to reach the livers may involve hematogenous and/or biliary system dissemination.