TLR2/TLR9激动剂对鲍曼不动杆菌肺部感染的保护作用  

Protective effect of TLR2/TLR9 agonists on pulmonary Acinetobacter baumannii infection in mice

作　　者：程浩 杨赟 孙红武[1] 邓炎 李郭成 曹静文 魏静 迟宇 李海波[1] CHENG Hao;YANG Yun;SUN Hongwu;DENG Yan;LI Guocheng;CAO Jingwen;WEI Jing;CHI Yu;LI Haibo(Department of Microbiology and Biochemical Pharmacy,National Engineering Technology Research Center for Immune Biological Products,Faculty of Pharmacy and Laboratory Medicine,Army Medical University(Third Military Medical University),Chongqing,400038;Clinical Medical School,Jiamusi University,Jiamusi,Heilongjiang Province,154007,China)

机构地区：[1]陆军军医大学(第三军医大学)药学与检验医学系微生物与生化药学教研室,国家免疫生物制品工程技术研究中心,重庆400038 [2]佳木斯大学临床医学院,黑龙江佳木斯154007

出　　处：《陆军军医大学学报》2024年第8期829-836,共8页Journal of Army Medical University

基　　金：国家自然科学基金面上项目(32270988)。

摘　　要：目的评价toll-like receptor(TLR)2/TLR9激动剂对肺部感染鲍曼不动杆菌(Acinetobacter baumannii,Ab)小鼠的保护作用。方法将6~8周龄雌性C57小鼠分为PBS组、Pam_(2)CSK_(4)(Pam)组、CpG ODN(CpG)组和Pam+CpG组,以不同剂量滴鼻免疫后24 h进行Ab肺部致死性感染,观察小鼠生存率。构建亚致死剂量Ab肺部感染模型,测定感染后小鼠血液、肺脏、肝脏、肾脏和脾脏的细菌定植量,并取小鼠肺脏和肾脏进行HE染色,分析病理损伤程度。探索免疫1、3、7 d后对小鼠Ab感染的保护作用,明确保护时间窗。Pam+CpG体外刺激A549上皮细胞和RAW264.7细胞,考察两种细胞对Ab的杀伤或吞噬作用。结果与PBS组比较,Pam+CpG组能显著提高Ab致死感染小鼠的生存率(P<0.05,P<0.01),降低亚致死感染后小鼠血液(P<0.01)、肺脏(P<0.01)、肝脏(P<0.05)、肾脏(P<0.01)和脾脏(P<0.01)的细菌定植量,减轻感染导致的病理损伤;在感染之前1 d或3 d免疫均可显著提高小鼠的生存率(P<0.05),其中免疫后3 d保护效果最好。与PBS、Pam、CpG组比较,Pam+CpG组可以显著促进A549上皮细胞和R AW264.7细胞对Ab的杀伤或吞噬作用(P<0.01)。结论TLR2/TLR9激动剂合用对Ab致死和亚致死感染均具有显著的保护作用,可能的机制是其促进了肺上皮细胞和巨噬细胞对Ab的杀伤或吞噬作用。Objective To investigate the protective effect of Toll-like receptor(TLR)2/TLR9 agonists,Pam_(2)CSK_(4)(Pam)and CpG ODN(CpG)on mice infected with Acinetobacter baumannii(Ab)in the lungs.Methods Female C57 mice(6~8 weeks old)were randomly divided into PBS,Pam,CpG and Pam+CpG groups.In 24 h after intranasal immunization with different doses of the corresponding agonists,the mice were given a lethal dose of Ab infection in the lungs,and the survival rates of the mice were observed.A sublethal dose lung infection model of Ab was then established,and the bacterial colonization in the blood,lungs,liver,kidneys and spleen was measured respectively in the mice after infection.HE staining was used to observe the pathological damages in the lungs and kidneys.The protective effect of the agonists in the immunized mice against Ab was examined at 1,3 and 7 d after immunization to explore the protective time window.Pam+CpG was used to stimulate A549 cells and RAW264.7 cells to investigate the killing or phagocytic effects on Ab.Results Compared to PBS,Pam+CpG treatment significantly improved the survival rate of the mice after a lethal dose of Ab lung infection(P<0.05,P<0.01),reduced bacterial colonization in the blood(P<0.01),lungs(P<0.01),liver(P<0.01),kidneys(P<0.01)and spleen(P<0.01)in the mice after sublethal challenge,and alleviated pathological damage caused by infection.Immunization at 1 or 3 d before infection significantly improved the survival rate(P<0.05),and the protective effect was the best in 3 d after immunization.Furthermore,compared to single PBS,Pam and CpG immunization,Pam+CpG significantly promoted the killing and phagocytic effects of A549 epithelial cells and RAW264.7 cells,respectively,against Ab(P<0.01).Conclusion Combined application of TLR2/TLR9 agonists exerts a significant protective effect on both lethal and sublethal infections of Ab,which might be by its promoting the killing or phagocytic effect of lung epithelial cells and macrophages against Ab.

关 键 词：鲍曼不动杆菌 TLR2 TLR9 滴鼻免疫 肺部感染 

分 类 号：R517.9[医药卫生—内科学] R563.1[医药卫生—临床医学] R977.6