[Effects of airborne fine particulate matters on pulmonary inflammation injury and Th17/Treg balance of sub-chronic exposure mice].

ABSTRACT

OBJECTIVE: To explore effects of fine particulate matters (PM 2.5) onpulmonary 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 PM2.5 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, bronchoalveolar 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. RESULTS: Th17-related cytokine IL-17 increased, but Treg-related cytokine IL-10 decreased significantly in BALF at 7.5 and 15 mg/kg BW PM2.5 exposure groups compared with control group (P < 0.05). Consistently, the relative mRNA expression of ROR-gammat (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.