克拉霉素对铜绿假单胞菌慢性肺部感染小鼠辅助性T淋巴细胞1型/辅助性T淋巴细胞2型免疫平衡的调节作用

Clarithromycin modulates T-helper cell type1/T-helper cell type 2 immune balance in mice with chronic Pseudomonas aeruginosa pulmonary infection

目的探讨克拉霉素对铜绿假单胞菌(PA)慢性肺部感染小鼠肺组织辅助型T淋巴细胞(Th)1/Th2免疫平衡的调节作用。方法将54只小鼠随机分入克拉霉素组、0.9%氯化钠溶液组和对照组。克拉霉素组和0.9%氯化钠溶液组通过小鼠气道接种由包裹PA的琼脂糖珠方法建立的PA慢性肺部感染模型,自建模后第7天起分别给予克拉霉素和0.9%氯化钠溶液治疗,对照组小鼠经气道接种无菌琼脂糖珠给予0.9%氯化钠溶液。分别于建模后第7、10、14天处死小鼠。标本进行肺组织细菌培养、病理学检查、支气管肺泡灌洗液(BALF)中γ-干扰素(IFN-γ)/白细胞介素(IL)-4水平测定和肺组织转录因子T-betmRNA/GATA-3mRNA表达水平分析。结果克拉霉素组小鼠在治疗后慢性肺部感染的症状明显改善。经气道接种后第7天,0.9%氯化钠溶液组和克拉霉素组BALF中IFN-γ、IL-4水平均显著高于对照组(P值均<0.05)。气道接种后第14天,克拉霉素组的IFN-γ水平显著低于0.9%氯化钠溶液组(P<0.05)。气道接种后第10、14天,克拉霉素组BALF中IL-4水平均显著高于0.9%氯化钠溶液组和对照组同时间点(P值均<0.05),而IFN-γ/IL-4比值均显著低于0.9%氯化钠溶液组同时间点(P值均<0.05)。气道接种后第7、10天,克拉霉素组与0.9%氯化钠溶液组的Th1、Th2细胞转录因子T-betmRNA、GATA-3mRNA表达水平相近,均显著高于对照组(P值均<0.05)。气道接种后第14天,克拉霉素组T-betmRNA表达水平、T-betmRNA/GATA-3mRNA比值均显著低于0.9%氯化钠溶液组(P值均<0.05)。结论在PA慢性肺部感染初期采用克拉霉素治疗可使小鼠肺组织的Th1/Th2平衡向Th2偏移,有利于缓解气道炎症。

Objective To investigate the effect of clarithromycin on T-helper cell type1 （Th1）/T-helper cell type 2 （Th2） immune balance in a mouse model of chronic Pseudomonas aeruginosa （PA） pulmonary infection. Methods Fifty-four BALB/c mice were randomly divided into clarithromycin group, saline group and control group （n = 18）. The mice in clarithromycin group and saline group were inoculated with PA-laden agarose beads to establish animal models of chronic PA pulmonary infection, and were treated with clarithromycin or normal saline from day 7 after inoculation. The mice in control group were inoculated with sterile beads and treated with normal saline. The mice were sacrificed on day 7, 10, and 14 after modeling. Bacterial culture and histopathological examination were conducted with the specimen. The mRNA level of interferon γ（IFN-γ）/ interleukin 4 （IL-4） and transcription factors （T-bet and GATA-3） were compared among three groups. Results Airway inflammation was significantly relieved in the mice of clarithromycin group. On day 7 after inoculation, the levels of IFN-γ, and IL-4 in both saline group and clarithromycin group were significantly higher than that in control group （all P〈0.05）. The IFN-γ level in clarithromycin group was significantly lower than that in saline group on day 14 after inoculation （P〈0.05）. The IL-4 level in clarithromycin group was significantly higher than that in saline group and control group onday 10 and 14 after inoculation （P〈0.05）. The ratios of IFN-γ to IL-4 were significantly down-regulated in clarithromycin group as compared with saline group on day 10 and day 14 after inoculation （all P〈0.05）. On day 7 and 10 after inoculation, the expression levels of T-bet mRNA and GATA-3 mRNA in saline group and clarithromycin group were significantly higher than that in control group （all P-〈0.05）, but there were no significant differences between saline group and clarithromycin group （all P〈0.05）. On day 14 after inoculation, the mRNA level of T-bet and the ratios of T-bet to GATA-3 in clarithromycin group were siginificantly lower than those in saline group （all P〈0.05）. Conclusion Therapeutic benefit of clarithromycin may be partially due to a shift in the immune systems from Th1 to Th2.