The role of NLRP3 inflammasome in immune response mechanism of Escherichia coli bloodstream infection / 安徽医科大学学报

ABSTRACT

Objective To investigate the immune reaction mechanism of NLRP3 inflammsome in the Escherichia coli bloodstream infection. Methods C57BL/6 mouses were injected by caudal vein with Escherichia coli and phosphate buffer ( PBS) respectively as injected group and control group. The infected group mice were executed after 24 hours and 48 hours,and the control group mice were executed at the beginning of experiment,taking the tis-sue samples of the two groups and detecting the changes of each index. The changes of the indexes were detected by enzyme-linked immunosorbent assay( ELISA) , real-time quantitative PCR ( RT-qPCR) , Western blot and HE stai-ning. Results Significant inflammatory cell infiltration and tissue necrosis were observed by HE staining in 24 h and 48 h after infection with Escherichia coli. The IL-1β and IL-18 cytokines in tissue homogenate and serum of bloodstream infection group were all increased significantly. The mRNA expression of NLRP3, ASC and caspase-1 in liver and lung homogenate increased significantly at 24 h after infection, while NLRP3, ASC and caspase-1 mR-NA in kidney homogenate increased significantly at 48 h after infection. The expression of NLRP3 protein and ASC protein in the liver, lung and kidney tissues of the 48 h group was significantly higher than that in the 24 h group, but there was no significant difference in pro-caspase-1 expression of liver and kidney tissues between three groups. The expression of NLRP3 protein and ASC protein in liver, lung and kidney tissues in 48 h group was significantly higher than that in 24 h group,the expression of pro-caspase-1 protein in liver and kidney tissue in three groups dis-played no significant difference,the expression of caspase-1 protein in lung and kidney tissues was increased with time. Conclusion Escherichia coli bloodstream infection is associated with the activation of NLRP3 inflammatory, and the expression level of NLRP3 inflammasome was related to the severity of infection, with the increase of infec-tion, NLRP3 inflammatory expression increased. The findings may provide a new idea for the treatment of sepsis caused by Escherichia coli bloodstream infection.