Therapeutic effects of quercetin on bleomycin induced pulmonary fibrosis in rats

The present study was performed to evaluate the role of quercetin in bleomycin (BLM)-induced pulmonary fibrosis (PF) in Sprague-Dawley rats. The rats after BLM administration received quercetin and were sacrificed on the days 12, 22 and 36 to measure the total protein content in bronchoalveolar lavage fluid (BALF). In addition, the hydroxyproline (HYP) content, malondialdehyde (MDA), the GSH/GSSG ratio and total anti-oxidative capability (T-AOC) were also evaluated. The results revealed that BLM treatment increased the BALF protein, HYP, MDA and T-AOC contents of the lung tissues and decreased GSH/GSSG ratio after 12 or 24 days. However, quercetin treatment for 24 days reversed the effect produced by BLM. In quercetin treated rats a marked reduction in HYP and total proteins was observed after 24 days. Quercetin prevented reduction in the expression of mRNA for MMP-1 and TIMP-1 at day 24 after treatment which was found to be reduced by BLM in untreated rats. Thus, quercetin exhibits a promising therapeutic effect in the prevention of PF.