盐酸美金刚促进中性粒细胞对耐甲氧西林金黄色葡萄球菌的抗菌作用及其机制

Memantine hydrochloride promotes the antibacterial effect of neutrophils against methicillin-resistant Staphylococcus aureus and the related mechanism

目的探索盐酸美金刚(memantine hydrochloride,MEM)促进中性粒细胞对耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)的杀菌作用并探索其分子机制。方法采用不同浓度的MEM与感染MRSA的中性粒细胞共孵育4 h后,取适量菌液涂LB平板培养、计数;收集共孵育后的中性粒细胞检测活性氧生成和中性粒细胞胞外诱捕网的释放情况。建立小鼠MRSA感染模型,给予或不给予MEM处理,收集血液、脾脏、肾脏进行菌落计数及血液中的降钙素原检测。MRSA感染小鼠后,腹腔注射MEM或PBS,记录48 h小鼠存活率,绘制生存曲线。结果与未加MEM组相比,MEM处理后的混合培养液中MRSA数量显著减少,且在一定浓度范围内,MRSA的存活数随着MEM浓度的升高而减少。此外,MEM能显著促进中性粒细胞产生活性氧以及胞外诱捕网的形成。动物实验显示,MEM组小鼠血清降钙素原浓度显著降低,血液及脏器中的载菌量显著降低,48 h小鼠存活率较PBS组显著升高。结论MEM能显著增强中性粒细胞对MRSA的杀菌作用,其机制可能是MEM促进了中性粒细胞活性氧和胞外诱捕网的产生。

Objective To investigate whether memantine hydrochloride(MEM)could promote the bactericidal effect of neutrophils against methicillin-resistant Staphylococcus aureus(MRSA)and the possible mechanism.Methods Neutrophils were co-incubated with different concentrations of MEM and MRSA for 4 h.Then the cell lysates were collected and cultured on plate for survival bacteria counting.After co-incubation,the neutrophils were collected to detect the production of reactive oxygen species(ROS)and the release of neutrophil extracellular traps(NETs).A mouse model of MRSA infection was established,and then the mice were treated with or without MEM.Blood,spleen and kidney samples were collected from the mice for bacterial colony counting and blood procalcitonin(PCT)detection.In the 48 h survival experiment,the mice were first infected with MRSA,and then treated with MEM or PBS.The survival rates of the mice were calculated and the survival curves were drawn.Results The number of MRSA co-cultured with neutrophils decreased significantly in the presence of MEM,and within a certain concentration range,the survival number of MRSA decreased with the increase of MEM concentration.Moreover,MEM could significantly promote the production of ROS by neutrophils and the formation of NETs.In vivo experiment showed that the concentration of PCT in mouse blood samples was lower in the MRSA+MEM group than in the MRSA+PBS group.The animal experiment also revealed that MEM significantly decreased the bacteria loads in mouse blood and organs and increased the 48 h survival rate after MRSA infection.Conclusions MEM could significantly promote the bactericidal effect of neutrophils against MRSA,which might be related to the enhanced generation of ROS by neutrophils and the formation of NETs.