The Effect of Methanol Extract of Fennel on Bleomycin-Induced Pulmonary Fibrosis in Rats

Idiopathic pulmonary fibrosis (IPF) is a chronic diffuse interstitial lung disease, which has symptoms such as coughing and shortness of breath. The average survival duration in these patients is estimated as 3 years after the onset of symptoms. Today, the therapeutic approach used in IPF cases is the usage of chemical or herbal antioxidants in order to eliminate free radicals and prevent inflammation and fibrosis. Considering the antioxidant properties of fennel, this research was conducted to investigate the effect of the methanol extracted of fennel on bleomycin-induced pulmonary fibrosis in rats. To induce pulmonary fibrosis in rats, intratracheal administration of 15 mg bleomycin was conducted in 52 male rates. Subsequently, the rats were injected intraperitoneally with 500 mg/(kg body weight) of methanol extract of fennel 14-day and 28-day periods. The samples were studied in terms of inflammation, fibrosis, hydroxyproline concentration, lipid peroxidation, and the catalase activity of lung tissue. The obtained results were analyzed using SPSS software. The degree of inflammation, fibrosis, hydroxyproline and lipid peroxidation concentration in lung tissue in the fennel methanol extract group had significantly decreased compared to other groups. In addition, a significant increase was observed in tissue catalase concentration in this group in comparison to other groups on days 14 and 28. The obtained results illustrated that the methanol extract of fennel may be efficient in the prevention and treatment of pulmonary fibrosis due to its antioxidant properties. Accordingly, it can be suggested for the prevention and treatment of pulmonary fibrosis instead of corticosteroids and immunosuppressant drugs due to their many side effects and most patients’ preference of herbal medicines.