Triptolide attenuates bleomycin-induced pulmonary fibrosis in mice through inhibiting ferroptosis
AIM:To investigate the effect of triptolide(TPL)on bleomycin(BLM)-induced pulmonary fibro-sis in mice and to demonstrate the molecular mechanisms of ferroptosis involved in the TPL-derived improvement of pulmo-nary fibrosis.METHODS:Specific pathogen-free(SPF)mice were randomly divided into 3 groups:control group,mod-el group(BLM treatment)and experimental group(BLM+TPL treatment),with 10 mice in each group.At Day 0,the model mice and the experimental mice were intratracheally perfused with BLM(50 μL,5 mg/kg),while the control mice were perfused with saline buffer.From Day 1,the mice in experimental group were administrated orally with TPL suspen-sion(200 μL,0.25 mg/kg),once per 3 d with continuous 7 times.The mice in control group and model group received the same volume of saline.The pulmonary fibrosis and cell apoptosis in lung tissues were detected using Masson staining and TUNEL staining,respectively.Furthermore,cell viability and apoptosis in vitro were examined by CCK8 assay and flow cytometry as well as live/dead cell staining.Cellular lipid peroxidation was detected by immunofluorescence.Finally,Western blot was performed to detect the expression of target proteins in lung tissues and cells.RESULTS:Treatment with TPL significantly reduced the fibrosis in lung tissues of BLM-induced mice(P<0.01)via down-regulation of collagen type I(Col I)and α-smooth muscle actin(α-SMA)expression(P<0.05).Simultaneously,TPL treatment significantly in-creased the expression of glutathione peroxidase 4(GPX4)and ferroptosis suppressor protein 1(FSP1)and reduced trans-ferrin receptor 1(TfR1)expression(P<0.05),thus inhibiting BLM-induced ferroptosis and reducing the apoptosis(P<0.01).Clearly,TPL treatment inhibited BLM-induced apoptosis of alveolar epithelial cells(P<0.01).Further studies in-dicated that TPL treatment not only attenuated cellular lipid peroxidation(P<0.01),but also improved the expression of GPX4 and FSP1(P<0.01)and down-regulated TfR1 expression(P<0.05)in BLM-induced alveolar epithelial cells in vi-tro,contributing to the reduction of BLM-induced apoptosis by inhibiting ferroptosis.CONCLUSION:Triptolide could inhibit BLM-induced ferroptosis and improve the viability of pulmonary cells,thereby attenuating the degree of pulmonary fibrosis in mice.Together,these data provide theoretical support for the clinical application of TPL in the treatment of pul-monary interstitial diseases.
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万方数据
维普
