Circulating miRNAs might be promising biomarkers to reflect the dynamic pathological changes in smoking-related interstitial fibrosis.

Cigarette smoking is the major risk factor for smoking-related interstitial fibrosis (SRIF). Despite recent advances, the molecular mechanisms involved in the initiation and progression of this disease remain elusive. We found 6 months of chronic mainstream smoking exposure induced SRIF in C57 mice, which was associated with pronounced enhanced oxidative stress, bronchoalveolar inflammation and fibrosis but not apoptosis of alveolar septal cell. We used Affymetrix microRNA (miRNA) arrays to determine the temporal alteration in global gene expression of peripheral blood during the progression of diffuse pulmonary interstitial fibrosis in C57 mice. Microarray analysis revealed the upregulation of 3 miRNAs (miR-92b, miR-700 and miR-668) and the downregulation of 5 miRNAs (let-7e, miR-142-5p, miR-350, miR-19a and miR191*) in the peripheral blood of mice exposed to mainstream smoking for 1, 2, 3 and 6 months. We proposed that circulating miRNAs might be promising biomarkers to reflect the dynamic pathological changes of SRIF related interstitial fibrosis.