Protective effects of naringin against paraquat-induced acute lung injury and pulmonary fibrosis in mice

The present study evaluates protective effects of naringin against paraquat (PQ)-induced acute lung injury (ALI) and pulmonary fibrosis in mice. Survival probability against PQ intoxication was tested by a single intraperitoneal injection of PQ. Results showed that survival rates of mice exposed to PQ only (50 mg/kg within 7 days) were much lower than that in mice daily treatment with NAC or naringin. Moreover, protection against PQ-induced ALI was tested by daily pretreatment mice with saline, NAC or naringin for 3 days before PQ (30 mg/kg, i.p.). Results showed that increase in leukocytes infiltration and overexpressions of TNF-α and TGF-β1 caused by 8 h of PQ exposure were dose-dependently ameliorated by naringin. Furthermore, protection against PQ-induced pulmonary fibrosis was tested by pretreatment mice with PQ (20 mg/kg, i.p.), and then daily administration with saline, NAC or naringin for prolonged 21 days. Results showed that naringin of 60 and 120 mg/kg significantly reduced PQ-induced upregulations of TNF-α, TGF-β1, MMP-9 and TIMP-1, levels of pulmonary malonaldehyde and hydroxyproline, as well as pulmonary fibrosis deposition, while increased activities of SOD, GSH-Px and HO-1. These results indicated that naringin had effective protection against PQ-induced ALI and pulmonary fibrosis.