摘要
Abstract
[Objective] To test the potential effect and mechanism of melatonin (MT) on silica induced pulmonary fibrosis in rats.[Methods] Totally 72 specific-pathogen-free SD male rats were randomly divided into four groups (n=18 for each group):control,MT,dust exposure,and MT+dust exposure groups.The rats in the control group and the MT group were injected with 1 mL saline by intratracheal instillation,and those in the other two groups were injected with 1 mL silica suspension (50 mg/mL) by intratracheal instillation.After administration of silica or saline,the MT group and the MT+dust exposure group were additionally intraperitoneally injected with MT (10mg/kg),while the control group and the dust exposure group were intraperitoneally injected with saline (10 mL/kg) every day.Six rats of each group were sacrificed 7,14,and 28 days after exposure.Pulmonary organ coefficient was calculated and lung histomorphology was observed for each group.Hydroxyproline (Hyp) content,superoxide dismutase (SOD) activity,malondialdehyde (MDA) content,and the expression of nuclear factor kappa B (NF-κB) protein in lung tissues were evaluated.[Results] The MT+ dust exposure group showed reduced lung inflammation,congestion,edema,and interstitial fibrosis compared with the dust exposure group.Compared with the dust exposure group at the same stage,the pulmonary organ coefficients,Hyp content,and MDA content were decreased,while the SOD activity was increased in the MT+dust exposure group (Ps ＜0.05).Western blot analysis results showed that the expression of NF-κB protein (0.36 ± 0.02) in lung tissue of the MT+dust exposure group was lower than that of the dust exposure group (0.48 ± 0.01) (P＜0.05).[Conclusion] MT has a protective effect on silica induced lung fibrosis in rats.Its mechanism may be related to the improvement of oxidant/antioxidant system imbalance and anti-inflammatory,thus reducing fibrosis.关键词
褪黑素/矽肺/大鼠/抗氧化/肺纤维化Key words
melatonin/dust exposure/rat/antioxidation/pulmonary fibrosis分类
医药卫生
