中文摘要：

目的研究大气细颗粒物（PM2.5）亚慢性染毒对小鼠肺部炎症的影响，以及Th17／Treg细胞及其相关细胞因子的改变。方法将32只C57BL／6雄性小鼠随机分为4组，每组8只。PM。染毒低、中、高剂量组分别为1．5、7．5和15mg／kgBW，对照组给予相同体积的生理盐水。采用气管滴注的方式进行染毒，每周2次，连续染毒3个月。末次暴露24h后，麻醉动物，经气管肺泡灌洗收集肺泡灌洗液（BALF），ELISA法测定BALF中细胞因子IL-6、IL．17、IL-10和TGF-β的含量。Real．timePCR法测定肺组织中Th17细胞特异性转录因子ROR-γt及Treg细胞特异性转录因子Foxp3-4-mRNA的相对表达量。未经灌洗的左肺用4％多聚甲醛固定，进行病理学观察。结果中、高剂量PM2.5暴露引起小鼠BALF中IL-17显著升高，IL-10显著降低（P〈0．05）。肺组织中ROR-γt mRNA表达量随染毒剂量的增加而升高，而Foxp3＋mRNA表达量则随染毒剂量的增加呈降低趋势。结论大气细颗粒物亚慢性染毒可引起小鼠肺部持续的炎症、免疫损伤，导致Th17／Treg细胞失衡及其相关细胞因子分泌的改变。

英文摘要：

Objective To explore effects of fine particulate matters （PM2.5） on pulmonary inflammation, and the changes of Th17/Treg balance as well as related cytokines. Method Thirty-two C57BL/6 male mice were randomly divided into 4 groups including 1 saline control group and 3 PMa5 exposure groups（ 1.5,7.5 and 15 mg/kg BW, respectively）. Each group received intratracheal instillation twice per week for 3 consecutive months. 24 hours after the last exposure, anaesthetize the mice with chloral hydrate, bronehoalveolar lavage fluid （BALF） was collected for inflammatory cells and cytokines analysis. The Th17- and Treg-related cytokines in BALF was measured by enzyme linked immunosorbent assay （ELISA）. The level of the specific transcription factors of Th17 and Treg in lung tissue was determined by real-time PCR. Unlavaged left lung were fixed with 4 % paraformaldehyde for histopathological detection. Result Th17-related cytokine IL-17 increased,but Treg-related cytokine IL-10 decreased significantly in BALF at 7.5 and 15 mg/kg BW PM2.s exposure groups compared with control group（P 〈 0.05）. Consistently, the relative mRNA expression of ROR-γt （specific transcription factors of Th17） increased in a dose-response way,the relative mRNA expression of Foxp3 ＋ （specific transcription factors of Treg） decreased in a dose-response way. Conclusion Sub-chronic PM2.5 exposure caused persistent inflammation,immune injury and disordered the Th17 /Treg imbalance as well as related cytokines.