南方医科大学学报

南方医科大学学报 ›› 2020, Vol. 40 ›› Issue (02): 211-218.doi: 10.12122/j.issn.1673-4254.2020.02.20

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鼠李糖乳杆菌效应蛋白HM0539增强小鼠对大肠杆菌O157:H7肠道感染的抵抗力

张汉运，高 杰，何肖龙，龚泽龙，万 宇，胡彤彤，李煜彬，曹 虹   

  • 出版日期:2020-03-14 发布日期:2020-02-20
  • 基金资助:

The postbiotic HM0539 from Lactobacillus rhamnosus GG prevents intestinal infection by enterohemorrhagic E. coli O157: H7 in mice

  

  • Online:2020-03-14 Published:2020-02-20

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摘要： 目的 探究鼠李糖乳杆菌LGG的效应蛋白HM0539对大肠杆菌O157∶H7肠道感染的预防效果。方法 采用黏附、侵袭实验评价HM0539处理后，大肠杆菌O157∶H7对HT-29细胞的黏附侵袭能力。通过免疫荧光、免疫印迹等方法进一步检测在使用HM0539治疗过程中对HT-29细胞中黏蛋白（MUC2）、紧密连接蛋白（ZO-1）表达的影响；通过动物实验，观察小鼠的生存率及体质量变化，检测攻毒小鼠的肠道病理及肠道屏障功能的改变。结果 HM0539呈浓度依赖性地抑制大肠杆菌O157∶H7黏附和侵袭HT-29，且HM0539的预处理效果优于共同处理（P<0.05）；免疫荧光和免疫印迹等结果显示，HM0539不仅可以明显降低大肠杆菌O157∶H7感染后MUC2的表达水平（P<0.05），还可显著抑制其对细胞间紧密连接蛋白的破坏（P<0.05）。动物实验结果证 明HM0539可抑制攻毒小鼠的体质量下降（P<0.05）和空肠的损伤；HM0539可抑制大肠杆菌O157∶H7诱导的空肠杯状细胞的破坏（P<0.05）；此外，HM0539可上调攻毒小鼠空肠中的MUC2、ZO-1蛋白的表达（P<0.05）。结论 HM0539可抑制大肠杆菌O157∶H7黏附和侵袭HT-29细胞，而且增强了小鼠对大肠杆菌O157∶H7感染的抵抗力，其机制可能是通过抑制大肠杆菌O157∶ H7破坏黏蛋白和细胞间紧密连接蛋白。

Abstract: Objective To assess the protective effect of the novel postbiotic HM0539 from Lactobacillus rhamnosus GG against intestinal infection by enterohemorrhagic E. coli O157: H7. Methods We performed adhesion and invasion experiments to evaluate whether HM0539 could block E. coli O157: H7 adhesion to HT-29 cells. The expressions of mucin2 and the tight junction proteins ZO-1 and Occludin in HM0539-treated HT-29 cells were analyzed using immunofluorescence assay and Western blotting. Animal experiments were conducted in mice to observe the survival rate and changes in body weight, intestinal morphology and the intestinal barrier function after the challenge and HM0539 treatment. Results HM0539 significantly inhibited the adhesion and invasion of E. coli O157: H7 to HT-29 cells in a dose-dependent manner. HM0539 treatment 4 h prior to E. coli O157: H7 challenge significantly lowered the adhesion and invasion rates of bacteria as compared with the treatment administered at the same time of challenge (P<0.05). E. coli O157: H7-induced down-regulation of mucin2 and tight junction proteins in HT-29 cells was obviously alleviated by HM0539 treatment of (P<0.05). In the animal experiment, HM0539 treatment significantly inhibited body weight loss (P<0.05), alleviated jejunal injury, and inhibited E. coli O157: H7-induced destruction of jejunal goblet cells in the challenged mice (P<0.05). HM0539 also significantly up-regulated the expression of mucin2 and ZO-1 proteins in the jejunum of E. coli O157:H7-infected mice (P<0.05). Conclusion HM0539 not only inhibits the adhesion and invasion of E. coli O157: H7 to HT-29 cells, but also enhances the resistance against E. coli O157: H7 infection in mice by attenuating the destruction of mucin and tight junction proteins.