RNA extraction and Quantitative RT-PCR
Total RNA of lung tissues was extracted using a TRIzol reagent (TaKaRa, Dalian, China) and was revered to cDNA by One-Step gDNA Removal and cDNA Synthesis SuperMix (TransGen Biotech, Beijing, China) according to the manufacturer’s instruction. The gene expression of inflammatory cytokines and tight junction were performed using a 7500 real-time PCR system (Applied Biosystems, Foster, CA) with FastStart SYBR Green PCR Master Mix (Roche, Mannheim, Germany). Data were expressed as an n-fold difference relative to the expression of inner housekeeping gene β-actin. The primer sequences was shown in Table S11.