Protective effects of C-type natriuretic peptide on bleomycin-induced pulmonary fibrosis in mice

Objective To study the effects of C-type natriuretic peptide on the bleomycin (BLM)-induced pulmonary fibrosis in mice. Methods The mice were given an intratracheal injection of BLM or 0.9% saline and assigned to receive continuous infusion of CNP or vehicle,and then divided into three groups:the control group,BLM group,and BLM group treated with CNP. All animals received bronchoalveolar lavage at the 1st,3rd,7th,and 14th days. The BAL fluid was reserved for determination of the number of cells,cell differentiation,and the contents of IL-1β. Fourteen days after BLM injection,the animals were sacrificed,and the change in histomorphology of lung tissues and the content of hydroxyproline in lung homogenate were assessed. Results The pulmonary fibrosis and inflammatory reaction in the BLM mice were more obvious than in the other two groups. CNP could relieve the damage of BLM,and could increase the survival rate. Conclusion CNP can attenuate BLM-induced pulmonary fibrosis by interfering in inflammatory reaction and fibrous degeneration.