Abstract：Objective: To investigate the activation of Raw 264.7 cell inflammasome by Acinetobacter baumannii(A. baumannii) with different capsule thickness. Methods: A. baumannii capsule was stained by Congo red, and selected two strains with significant differences in capsule thickness. The Raw 264.7 cells were infected with two strains of bacteria, and the cells culture was collected in 6 h. The gene expression of NODlike receptors(NLRP3), caspase1 and IL1β were determined by realtime PCR. The level of reactive oxygen species(ROS) in Raw 264.7 cells was determined by flow cytometry in 1 h, 3 h and 6 h. Results: The capsule around A. baumannii could not be stained by Congo red, and it was easy to be observed. The expression of NLRP3, caspase1 and IL1β mRNA in Raw 264.7 cells infected by two strains of A. baumannii were increased significantly compared with normal cell control. The expression of NLRP3 and IL1β in thick capsular strain was significantly higher than that of the thin capsular strain（P<0.05）, and there was no significant difference in caspase1 expression between the two strains. Both the two strains could upregulate the ROS production of Raw 264.7 cells. The ROS production in two strains infection group was significantly higher than that of normal cells control in 3 h and 6 h（P<0.05）, and the ROS production in the thick capsular strain group was significantly higher than that of the thin capsular strain group（P<0.05）. Conclusion: A. baumannii with different capsule thickness showed different activation abilities of inflammasome in Raw 264.7 cell, and the activation ability of inflammasome induced by the thick capsule strain was stronger.
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2019, Vol. 29 
