苦参碱对慢性铜绿假单胞菌生物膜肺部感染大鼠的免疫保护作用

Effects of Matrine on Immune Protection in A Rat Model of Chronic Pseudomonas aeruginosa Biofilm Pneumonia

目的:探讨苦参碱对慢性铜绿假单胞菌(PA)生物膜肺部感染大鼠的免疫保护作用及其机制。方法:由支气管内直接注入PA(菌种为PAO579)藻酸盐微粒(1×109 CFU/mL),建立慢性PA生物膜感染模型,并于术后第2d开始给予苦参碱注射液(Mat,100mg·kg-1)或灭菌生理盐水(NS)ip,每天1次,连续治疗14d。2周后评估各组的肺部细菌学、病理学、肺部细胞因子白介素(IL-4),干扰素γ(IFN-γ)反应的变化。结果:PA感染2周后,苦参碱可显著减轻肺部大体观病理改变(P<0.001),肺脓肿发生率明显低于模型组(P<0.001)。镜检发现有80%的动物已由急性炎症(以多形核白细胞浸润为主)逆转为慢性炎症(以单个核细胞浸润为主),显著高于模型组的比例(P<0.05);苦参碱治疗组肺组织匀浆PA菌落计数仅为模型组1/20(P<0.001),PA检出率仅为50%(P<0.05),肺部细菌清除速度显著加快;另外,与模型组比较,苦参碱治疗2周后感染动物肺部IL-4水平明显下调(P<0.001),而肺部IFN-γ水平显著升高(P<0.001)。结论:以上结果提示苦参碱能够诱导肺部Th1型免疫反应,加快PA生物膜肺炎大鼠肺部的细菌清除及减轻肺部病理损伤,因而对PA生物膜肺感染大鼠具有免疫保护作用。

Objective：To observe the immune protection of matrine （ Mat） on a rat model of chronic Pseudomonas aeruginosa （ PA） biofilm pneumonia.Method：Rats were challenged intratracheally with alginate embedded PA strain PAO579 in the concentration of 1×109 colony-forming units per milliliter（CFU·mL^-1）.Mat or sterile normal saline （NS） was injected intraperitoneally once a day for two weeks starting on the second day after challenge.Two weeks post intratracheal challenge with PA,parameters were evaluated.Result：Two weeks after challenge,the Mat-treated group showed a significantly milder pathological changes in lung（P〈0.001）,and lower lung abscess incidence compared to the model group（ P〈0.001）.Furthermore,a remarkable improved bacterial clearance（P〈0.001） and a shift from an acute type to a chronic type of lung inflammation were found in the Mat-treated group compared to the model group.80% animals have returned to a chronic type of lung inflammation after Mat treatment which were much higher than that in the model group（P〈0.05）.The lung cells from the Mat-treated group produced more interferon-gamma（IFN-γ）（P〈0.001）,but less interlerkin-4（IL-4）（P〈0.001）as compared to the model group.These results indicate that Mat has an effect of inducing Th1 type of immune response.Conclusion：Mat treatment significantly reduced pathological changes in lung and enhanced lung bacterial clearance,which might be associated with a shift of local immune responding type from a Th2 like to Th1 like.This might provide a better immune protection to the rats with chronic P.aeruginosa bilfilm lung infection.