鲍曼不动杆菌对RAW264.7巨噬细胞的损伤效应及Siglec-G的调控作用OACHSSCD

Objective To investigate the damaging effects of Acinetobacter baumannii(A.baumannii)on mouse macrophages and the regulatory role of Siglec-G,and to analyze the characteristics of its pneumonia model.Methods RAW264.7 cells were co-cultured with A.baumannii to assess cell viability and inflammatory cytokine levels;changes in inflammatory cytokines were observed following siRNA-mediated inhibition of Siglec-G expression.A mouse pneumonia model was established via tracheal instillation to evaluate lung pathology,inflammatory cytokines,proteins,and cell counts in bronchoalveolar lavage fluid(BALF),as well as the wet-to-dry lung weight ratio.Results A.baumannii induced RAW264.7 cell death in a time-and dose-dependent manner and markedly elevated the levels of TNF-α and IL-6 in the cell supernatant.Knockdown of Siglec-G markedly decreased the secretion of IL-6 induced by bacteria,while it had no obvious effect on TNF-α production.In the absence of infection,knocking down Siglec-G reduced the basal expression level of TNF-α.In vivo,significant inflammation was observed in the lungs of mice 24 h after infection,with elevated levels of inflammatory cytokines,proteins,and total cell counts in BALF;however,the wet-to-dry lung weight ratio did not change significantly.Conclusion A.baumannii can directly damage macrophages and induce an inflammatory response,while Siglec-G selectively regulates IL-6 production.The mouse pneumonia model exhibits rapidly progressing inflammation rather than severe pulmonary edema.