Protective and therapeutic effects of ethanolic extract of Nasturtium officinale (watercress) and vitamin E against bleomycin-induced pulmonary fibrosis in rats

Background and purpose: Pulmonary fibrosis is a chronic disease of the lungs caused by inflammation, species of reactive oxygen, and immune defects. Antioxidant properties of Nasturtium officinale has been reported in some studies. Therefore, the objective of the current study was to evaluate the effect of ethanolic extract of Nasturtium officinale (EENO) on bleomycin (BLM)-induced lung fibrosis in rats. Experimental approach: Forty adult male Wistar rats (180-220 g) were randomly divided into 5 experimental groups. Normal control, BLM control received a single dose of BLM (6 IU/kg) intratracheally only on the first day, EENO + BLM group received EENO (500 mg/kg) one week before intratracheal BLM instillation and two weeks afterward, BLM + EENO group and BML + vitamin E group received EENO (500 mg/kg) and vitamin E (500 mg/kg) half-hour after BLM installation, respectively. The animals were sacrificed on day 22. Change in body weight, lung index, serum level of malondialdehyde (MDA) and nitric oxide (NO) metabolite, lung tissue hydroxyproline content and lung pathology were assessed. Findings/Results: Pre- or post-treatment with EENO attenuated pulmonary fibrosis as evidenced by normalized lung index, improved histological changes and inhibited collagen deposition (hydroxyproline) in the animal lung. EENO also decreased MDA and NO metabolite release in comparison to the BLM control. vitamin E (500 mg/ kg) also significantly inhibited the BLM-induced lung toxicity. Conclusions and implications: EENO can prevent BLM-induced lung fibrosis in rats via antioxidant activities. However, more studies are needed to elicit the exact mechanism of this effect.