小鼠感染猪致病性大肠杆菌模型的构建与病理研究OA北大核心

Porcine pathogenic Escherichia coli,is an important pathogen that causes intestinal disease,septicaemia and urinary tract infections.In order to explore the injury mechanism induced by pathogenic Escherichia coli,this experiment randomly divides 50 8-to 9-week-old Babl/c female mice into 10 groups,with 5 mice in each group.Four model groups are intraperitoneally injected with 300 μL E.coli at concentrations of 1×106 cfu/mL,1×107 cfu/mL,1×108 cfu/mL,1×109 cfu/mL respectively,while the control group mice are intraperitoneally injected with an equal volume of sterilized PBS.After 72 hours of observation,the histopathological changes are observed and the cellular inflammatory factors interleukin-2(IL-2)and interleukin-6(IL-6)are detected.The prokaryotic expression vector expressing green fluorescent protein(GFP)is transformed into pathogenic E.coli EC2316 by electroporation transformation method,and the strain EC2316-GFP expressing green fluorescence is obtained.The results show that the median lethal dose of strain EC2316 is 2×107 cfu/mL.The bacterial colonization in organs increases with rising bacterial concentration,and IL2 and IL-6 increased significantly.The introduction of GFP did not alters the growth characteristics of strain EC2316.In summary,the pathological changes and inflammatory responses observed in mice infected with porcine pathogenic E.coli closely resemble those documented in naturally occurring cases.A mouse model of porcine pathogenic E.coli infection is successfully established,which provides theoretical and practical foundation for further research into the damage mechanisms caused by E.coli.