Effects and mechanisms of pirfenidone, prednisone and acetylcysteine on pulmonary fibrosis in rat idiopathic pulmonary fibrosis models

CONTEXT: Previous studies have reported that caveolin-1 (Cav-1) is associated with lung fibrosis. However, the role of Cav-1 expression in pirfenidone-treated idiopathic pulmonary fibrosis (IPF) is unknown. OBJECTIVE: This study investigated Cav-1 expression in pirfenidone-treated IPF, and compared the effects of pirfenidone with acetylcysteine and prednisone on IPF. MATERIALS AND METHODS: Rat IPF model was established by endotracheal injection of 5 mg/kg bleomycin A5 into the specific pathogen-free Wistar male rats. Pirfenidone (P, 100 mg/kg once daily), prednisone (H, 5 mg/kg once daily) and acetylcysteine (N, 4 mg/kg 3 times per day) were used to treat the rat model by intragastric administration for 45 consecutive days, respectively. The normal rats without IPF were used as the controls. After 15, 30 and 45 days of drug treatment, lung histopathology was assessed. The expression of Cav-1 was determined using real-time quantitative PCR and Western blot; the expression of tumour necrosis factor-α (TNF-α), transforming growth factor-β1 (TGF-β1) and platelet-derived growth factor (PDGF) was determined by enzyme-linked immunosorbent assay. RESULTS: After 15, 30 and 45 days of drug treatment, comparison of the three drug-treated groups with the model group showed significantly lower (p < 0.05) significance of airsacculitis and fibrosis scores of lung tissues, as well as expression of TGF-β1, TNF-α and PDGF, but the expression of Cav-1 was higher (p < 0.05). Compared with the N group, the fibrosis score was significantly lower and the protein expression of Cav-1 was significantly higher in the P group (p < 0.05). Additionally, the expression of Cav-1 was negatively correlated with the airsacculitis and fibrosis scores (r = -0.506, p < 0.01; r = -0.676, p < 0.01) as well as expression of TGF-β1, TNF-α and PDGF (r = -0.590, p < 0.01; r = -0.530, p < 0.01; r = -0.553, p < 0.01). DISCUSSION AND CONCLUSION: Pirfenidone, prednisone and acetylcysteine can inhibit airsacculitis and pulmonary fibrosis in rat IPF models, which may be related with enhanced caveolin-1, reduced TNF-α, TGF-β1, PDGF.