重组白细胞介素17F对肺炎支原体感染小鼠体内防御素β-2及巨噬细胞炎性蛋白表达的影响

Effects of Recombinant Interleukin 17F on Expressions of β-Defensin-2 and Macrophage Inflammatory Protein in Murine Mycoplasma Pneumoniae Infection Mice

目的观察重组白细胞介素17F(rIL-17F)对肺炎支原体(MP)感染小鼠体内防御素β-2(Defb-2)及巨噬细胞炎性蛋白(MIP)表达的影响,探讨rIL-17F防御MP感染的相关机制。方法 SPF级BALB/c小鼠随机分为感染组、干预组和对照组,以鼻腔接种的方式建立MP感染模型,以鼻腔黏膜免疫方式进行rIL-17F干预。采用荧光定量PCR法检测其肺组织Defb-2、MIP-1α、MIP-2βmRNA的表达水平,ELISA法检测其肺泡灌洗液(BALF)、脾脏及纵隔淋巴结细胞培养上清中MIP-1α、MIP-2β、IL-4、IFN-γ水平。结果 1.干预组MP菌落计数明显低于感染组,BALF中白细胞总数及中性粒细胞、巨噬细胞计数明显高于感染组,差异均有统计学意义。对照组无菌落生长。感染组BALF中白细胞总数及中性粒细胞、巨噬细胞计数明显高于对照组,差异均有统计学意义。2.干预组肺组织Defb-2、MIP-1α和MIP-2βmRNA表达水平均明显高于感染组,差异有统计学意义。3.干预组与感染组比较,MIP-1α水平在纵隔淋巴结细胞培养上清中明显升高,MIP-2β水平在BALF和纵隔淋巴结细胞培养上清中明显升高,差异均有统计学意义;IL-4水平在BALF中明显降低,在脾细胞培养上清中则明显升高,差异均有统计学意义;IFN-γ水平在脾细胞培养上清中明显升高,差异有统计学意义。感染组与对照组比较,MIP-1α水平在脾细胞及纵隔淋巴结细胞培养上清中均明显升高,差异有统计学意义;MIP-2β水平两组之间无显著差异;IL-4水平在BALF及脾细胞培养上清中均明显升高,差异有统计学意义;IFN-γ水平在BALF中明显升高,差异有统计学意义。结论 rIL-17F能促进Defb-2及MIP等炎性因子的表达,调节Th1/Th2平衡,增加感染部位中性粒细胞和巨噬细胞等炎性细胞的聚集,提高MP清除率,增强机体抗感染能力。

Objective To evaluate the effects of recombinant interleukin- 17F（ rIL- 17F） on expressions of β -defensin-2 （Defb- 2） and macrophage inflammatory protein （MIP） in murine mycoplasma pneumoniae（MP） infection mice. Methods BALB/c mice were di- vided randomly into MP infection group, rIL - 17F intervention group and control group. Before intranasal infection with MP, the mice were treated with phosphate buffered solution or rIL - 17F, respectively. The numbers of bacteria and leukoeytes in bronchoalveolar lavage fluid （BALF） were counted,and the mRNA levels of Defb -2, MIP - 1α and MIP -2β in lung tissue were detected by real -time fluorescent quantitative polymerase chain reaction, the concentrations of MIP - 1 a, MIP - 2β, IL - 4 and IFN - 3＇ in BALF, supernatants of spleen cell and mediastinal lymph node cell were assayed by enzyme linked immunosorbent assay. Results 1. Compared with the infection group,the neutro- phil and maerophage numbers in BALF were higher in intervention group, while the number of bacteria was lower. There was no bacteria in control group. Compared with the control group, the nentrophil and macrophage numbers in BALF were higher in infection group. 2. Compared with infection group,the mRNA expression levels of Defb -2, MIP - 1α and MIP -2β in lung tissue were higher in intervention group. 3. Compared with infection group, the level of MIP - 1α in lymph node cell culture supernatants was higher in intervention group;The levels of MIP -2β in BALF and lymph node cell culture supernatants were higher in intervention group;The level of IL -4 was lower in BALF in intervention group, while higher level of IL -4 was detected in spleen cell culture supernatants ;The level of IFN - 3＇ in spleen cell culture superna- tants was higher in intervention group. Compared with control group, the level of MIP - 1 α in spleen cell and lymph node cell culture superna- tants was higher in infection group; There was no significant difference in the level of MIP -2β between 2 groups;The level of IL- 4 was higher in BALF and spleen cell culture supernatants in infection group ; The level of fEN - 3＇ in BALF was higher in infection group. Conclu- sions Intranasal inoculation of rlL - 17F can promote pulmonary neutrophil and macrophage recruitment and increase bacterium clearance, enhance the host defense against MP infection through increasing the expression levels of defensins, MIP and regulating Thl/Th2 balance.