Epicatechin protective effects on bleomycin-induced pulmonary oxidative stress and fibrosis in mice

Lung fibrosis is a chronic and intermittent pulmonary disease, caused by damage to the lung parenchyma due to inflammation and fibrosis. Epicatechin (Epi) as a flavonoid has antioxidant and anti-inflammatory properties. This study was conducted to evaluate the effect of Epi on oxidative stress, inflammation and pulmonary fibrosis induced by bleomycin (BLM) in mice. Accordingly, animals were randomly assigned into two groups of 7 and 14 days to evaluate the role of Epi in the early oxidative and late fibrotic phases of BLM-induced pulmonary injury, respectively. Each group was divided into six subgroups include control, Epi 100 mg/kg, BLM, and BLM groups pretreated with 25, 50 and 100 mg/kg Epi, respectively, from three days before until 7 or 14 days after BLM. Lung tissue oxidative stress markers including the activity of superoxide dismutase, glutathione peroxidase, catalase and the levels of malondialdehyde and glutathione were determined. Furthermore, alveolitis and inflammation were evaluated by Szapiel grading scores. In addition, fibrotic markers including lung hydroxyproline content, level of transforming growth factor beta and Ashcroft fibrotic grading of lung fibrosis were examined. Epi exerted protective effects against BLM-induced pulmonary injury in a dose-dependent manner in two early and late phases of lung injury. Oxidative stress markers persisted until the late fibrotic phase, as pro-fibrotic events were present in the early oxidative phase of BLM-induced injury. Finally, it is concluded that Epi can protect the lung against BLM-induced pulmonary oxidative stress, inflammation and fibrosis.