NLRP3炎症小体表达水平与猪支原体肺炎的相关性研究

Swine mycoplasmal pneumonia is a chronic respiratory infectious diseases ,which caused by mycoplasma hyopneumoniae. It seriously theats the pig industry and results in huge economic losses. The NLRP3 inflammasome is the Intracellular receptor of the innate immune system. It plays an important role in a variety of viruses, bacteria, fungal infective inflammation, and plays an important role in the non-infectious inflammation, such as gout, arthritis and atherosclerosis. But the relation between the expression level of NLRP3 inflammasome and swine mycoplasma pneumonia and the question wheather NLRP3 inflammasome could be activated by mycoplasma hyopneumoniae have not been reported. Therefore, this project intends to establish the mycoplasma pneumoniae infection pig model, to study the expression and distribution of NLRP3 inflammasome (NLRP3, ASC, caspase 1) and its downstream molecules (IL - 1 β, IL - 18, IL - 33) in pig lung tissue at different infection stages. And observation the effect of reducing the expression of NLRP3 by taking advantage of NLRP3-miRNA lentivirus on the development of swine mycoplasmal pneumonia . Then to explore the relation between the expression level of NLRP3 inflammasome and swine mycoplasmal pneumonia, reveal the effect of NLRP3 inflammasome in the development of swine mycoplasmal pneumonia, to elucidate the pathogenesis of swine mycoplasmal pneumonia and provide theoretical basis for preventing swine mycoplasmal pneumonia.

猪支原体肺炎是由猪肺炎支原体引起的一种接触性慢性呼吸道传染病，给养猪业带来巨大损失。NLRP3炎症小体是细胞内固有免疫系统的感受器，在多种病毒、细菌、真菌感染性炎症及痛风、关节炎等非感染性炎症中发挥重要作用。但NLRP3炎症小体表达水平是否与猪支原体肺炎具有相关性，猪肺炎支原体是否能激活 NLRP3炎症小体，目前尚未见报道。因此，本项目拟建立猪肺炎支原体感染模型，研究NLRP3炎症小体（NLRP3、ASC、caspase-1）及其下游分子（IL-1β、IL-18、IL-33）在猪肺炎支原体感染病程不同阶段肺组织中的表达和分布，利用NLRP3-miRNA慢病毒对肺炎支原体感染猪进行体内干预，观测NLRP3基因表达下调对猪支原体肺炎的影响，以探究NLRP3炎症小体表达水平与猪支原体肺炎的相关性，揭示NLRP3炎症小体在猪支原体肺炎发生发展中作用，为阐明猪支原体肺炎的发病机制提供理论依据。

猪支原体肺炎给养猪业带来巨大损失。NLRP3炎症小体是细胞内固有免疫系统的感受器，在感染性炎症及非感染性炎症中均发挥重要作用。但NLRP3炎症小体表达水平是否与猪支原体肺炎具有相关性，目前尚未见报道。为了探究NLRP3炎症小体表达水平与猪支原体肺炎的相关性，揭示NLRP3炎症小体在猪支原体肺炎发生发展中作用，本研究建立了猪肺炎支原体感染模型，研究了NLRP3炎症小体（NLRP3、ASC、caspase-1）及其下游分子（IL-1β、IL-18、IL-33）在健康猪和猪肺炎支原体感染猪病程不同阶段的表达水平和分布，利用NLRP3-miRNA 慢病毒对肺炎支原体感染猪进行体内干预，观测NLRP3基因表达下调对猪支原体肺炎的影响。结果表明，NLRP3炎症小体及其下游分子在肺泡上皮细胞、气管、细支气管、气管分泌物、血管细胞中均有表达。猪感染猪肺炎支原体后，肺组织中NLRP3炎症小体及其下游分子的表达水平明显升高，在感染早期和中期表达较多，且在感染中前期或中期达到峰值后下降；感染猪血清中IL-1β、TNF-α、Caspase-1和ASC-1的表达水平也明显增加，在感染中前期或中期表达较多。NLRP3-miRNA 慢病毒干预后，猪支原体肺炎的肺部病变有所缓解，肺组织中NLRP3、IL-1β、ASC-1的 mRNA水平明显降低，IL-18、Caspase-1的 mRNA水平明显增加；肺组织中NLRP3蛋白水平明显降低，IL-1β、TNF-α、IL-18、IL-33的水平明显增加；干预组血清中IL-1β、IL-18的水平在感染28天也明显增加。以上结果说明，NLRP3炎症小体的表达水平与猪支原体肺炎具有相关性，且在猪支原体肺炎的发生发展中起着重要作用，尤其在早期和中期，其可作为猪支原体肺炎感染的检测指标。