Inhibition Of Bleomycin-Induced Pulmonary Fibrosis By Extract From Rosmarinus Officinalis In Rats

Pulmonary fibrosis is a fatal disease which is characterized by inflammation and formation of permanent scar tissue in lung. Current treatment for this disease is limited and mainly relies on slowing the progression of fibrosis by anti-inflammatory agent. In this study, we examined the application of diterpene phenol extract of Rosmarinus officinalis (DERO) as an anti-inflammatory agent for treating bleomycin (BLM) induced pulmonary fibrosis in rat model. After stimulating pulmonary fibrosis in Sprague-Dawley rats by endotracheal injection of bleomycin, oral administration of DERO was conducted with different dose (low, medium and high). Compared with NS group, infiltration of pro-inflammation lymphocytes and the collagen accumulation in the lung tissue of BLM group were significantly increased. However, with administration of DERO, cell infiltration and collagen deposition reduced significantly in medium dose and high dose groups, while little reduced was demonstrated in low dose group. Moreover, the expressions of Collagen-I, TGFBR2 and TGF-beta(1) genes were decreased as well in medium and high dose group. In conclusion, our study demonstrated that DERO may play a regulatory role in BLM-induced pulmonary fibrosis by inhibiting over-depositing of Collagen I. DERO could inhibit the expression of TGF-beta(1) and TGFBR2 to suppress the activation of pre-collagen I by TGF beta-Smad1 pathway as well.