3,4-dihydroxyphenylethanol suppresses irradiation-induced pulmonary fibrosis in adult rats.

The present study demonstrates the effect of DHPEA on suppression of irradiation-induced pulmonary fibrosis. A (60)Co irradiator was used to induce pulmonary fibrosis in a rat model at a dose of 22 Gy. The rats of the treatment and positive control group were intraperitoneally injected DHPEA (10 mg/kg) or dexamethasone (DEX; 5 mg/kg) daily for 30 days. Hydroxyproline assay was used to evaluate the fibrosis of pulmonary and lung tissue sections after irradiation. Hematoxylin and eosin (H&E) and Masson's trichrome stained lung section were used for alveolitis and fibrosis score analyses, respectively. Immunohistochemistry was used for surfactant protein-B (SPB) and α-SMA expression analysis. Western blot analysis was employed for analysis of nuclear transcription factor NF-E2-related factor 2 (Nrf-2) and its associated antioxidant enzymes like heme oxygenase-1 (HO-1) and NAD (P) H: quinone oxidoreductase-1 (NQO-1). Results revealed a significant decrease in mortality rates and lung index scores, decreased collagen deposition, reduced MDA content and enhanced superoxide dismutase (SOD) activity in DHPEA treated rats compared to DEX-treated rats. DHPEA treatment also inhibited (myo) fibroblast proliferation, and regulated serum levels of TGF-β1, IL-6, IL-10, and TNF-α. In addition, DHPEA-treatment activated Nrf-2 and its downstream antioxidant enzymes HO-1 and NQO-1. Thus DHPEA can be a promising agent for the suppression of irradiation-induced pulmonary fibrosis.