ABSTRACT
OBJECTIVE: Pulmonary fibhrosis is a disease of the connective tissues in the respiratory system. Nigella sativa has been used for the treatment of pulmonary diseases like asthma. This study investigated the early and late preventive effect of methanolic extract of N. sativa on a bleomycin- induced pulmonary fibrosis model. MATERIALS AND METHODS: This study was carried out using 52 rats. Pulmonary fibrosis was induced by a single endotracheal injection of bleomycin (5 mg/kg). Extract of N. sativa (500 mg/kg per day) or methylprednisolone succinate (4 mg/kg per day) was injected intraperitoneally in two periods (i.e. days 1-14 as early preventive group and days 15-28 days as late preventive group). The lung tissues were histologically examined at the end of each period and inspected for the amount of hydroxyproline and biomarkers of oxidative stress. RESULTS: The pulmonary inflammation and fibrosis were significantly decreased in groups treated with methylprednisolone and N. sativa extract compared to bleomycin group in both early and late prevention groups (p<0.001). The hydroxyproline concentration in pulmonary tissue was significantly decreased in N. sativa and methylprednisolone groups compared to the bleomycin group in both prevention groups (p<0.001). Significant reductions in lipid peroxidation (p<0.001) and increases in catalase activity were also observed in N. sativa and methylprednisolone groups compared to bleomycin group. CONCLUSION: This study suggested that N. Sativa extract is effective for early and late prevention of pulmonary fibrosis and inflammation. However, more studies are needed to identify its anti-inflammatory and anti-fibrotic mechanisms in the respiratory system.
ABSTRACT
CONTEXT: Myrtle (Myrtus communis L) has been used widely in traditional medicine for different respiratory disorders. Idiopathic pulmonary fibrosis (IPF) is an inflammatory disease characterized by progressive loss of lung function with poor prognosis. The pathogenesis of disease has not been completely elucidated, but probably persistent epithelial damages are involved. OBJECTIVE: Evaluation of biochemical and histopathological effect of preventive and therapeutic doses of myrtle against bleomycin (BLM)-induced pulmonary fibrosis (PF) in animal model. MATERIALS AND METHODS: Methanolic extract of M. communis was prepared by maceration method. Total flavonoid content was determined and experimentally PF was induced in rat with intratracheal instillation of a single dose of BLM (5 mg/kg) only on day 0. Myrtle antifibrotic effect was evaluated as preventive (50 mg/kg/day, intraperitoneal (i.p.) injection, from day 0-13) and therapeutic agent (50 mg/kg, i.p., from day 14-27) in comparison with methyl prednisolone (M-pred) (4 mg/kg, i.p. for 14 days). RESULTS: Parenchymal inflammation and fibrotic changes significantly were reduced by myrtle and M-pred. Significant decrease in hydroxyproline content and lipid peroxidation were observed in animals receiving myrtle extract while catalase activity was increased by myrtle. Improvement in inflammation and fibrosis was observed in myrtle group especially in the early phase of fibrosis (preventive regime). DISCUSSION AND CONCLUSION: Myrtle extract effectively inhibited the inflammation and fibrosis of lung parenchyma in both preventive and therapeutic methods. This effect might be due to the reduction of tissue inflammation and inhibition of oxidative stress. More studies are being carried out to find main mechanisms and separation of active compounds.
