Effect of C-typenatriuretic peptide on paraquat-induced pulmonary fibrosis in mice

Abstract

Objective To evaluate the effect of C-type natriuretic peptide (CNP) on paraquat-induced pulmonary fibrosis in mice. Methods Fifty-four male Kunming mice, aged 8-10 weeks, weighing 30-35 g, were randomly divided into 3 groups (n=18 each) using a random number table: control group (C group), pulmonary fibrosis group (PF group) and CNP group.Paraquat 10 mg/kg (in 0.1 ml of normal saline) was injected intraperitoneally once every 3 days for 5 times in total in PF and CNP groups, and in addition CNP 3 μg/kg (in 0.1 ml of normal saline) was simultaneously injected via the tail vein once every 2 days for 14 times in total in group CNP.The equal volume of normal saline was given instead of paraquat in group C. On days 1, 8 and 15 after the end of administation of paraquat, 6 mice were sacrificed, and lungs were removed for determination of wet to dry weight ratio (W/D ratio), hydroxyproline (HYP) content (using alkaline hydrolysis), and transforming growth factor-beta 1 (TGF-β1) content (using enzyme-linked immunosorbent assay) in lung tissues. Results Compared with group C, the W/D ratio and contents of HYP and TGF-β1 in lung tissues were significantly increased at each time point after the end of administation of paraquat(P<0.05), and the pulmonary fibrosis was obvious in group PF.Compared with group PF, the W/D ratio and contents of HYP and TGF-β1 in lung tissues were significantly decreased at each time point after the end of administation of paraquat(P<0.05), and the pulmonary fibrosis was significantly attenuated in group CNP. Conclusion CNP can reduce paraquat-induced pulmonary fibrosis in mice. Key words: Natriuretic peptide, C-type; Paraquat; Pulmonary fibrosis