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

摘要:

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2 d开始给予苦参碱注射液(Mat,100 mg ·kg^-1) 或灭菌生理盐水(NS)ip,每天1次,连续治疗14 d。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。

Abstract:

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.