[Protective effect and mechanism of Maiwei Yangfei Decoction on pulmonary fibrosis mice based on Nrf2 regulation of oxidative stress].

This study explored the effect and mechanism of Maiwei Yangfei Decoction(MWYF) on pulmonary fibrosis(PF) mice. MWYF was prepared, and its main components were detected by ultra-high-performance liquid chromatography-triple quadrupole tandem mass spectrometry(UPLC-MS/MS). Male C57BL/6J mice were randomly divided into a control group, a model group, a pirfenidone(PFD) group, and low-, medium-, and high-dose MWYF groups, with 10 mice in each group. The PF model was induced in mice except for those in the control group by intratracheal instillation of bleomycin(BLM), and model mice were treated with saline or MWYF or PFD by gavage the next day. The water consumption, food intake, hair, and activity of mice were observed daily. The pathological changes in lung tissues were observed by hematoxylin-eosin(HE) staining, Masson staining, and CT scanning. The level of hydroxyproline(HYP) in lung tissues was detected by alkaline hydrolysis. Immunohistochemistry was used to observe the expression of collagen type Ⅲ(COL3) and fibronectin. The mRNA expression levels of α-smooth muscle actin(α-SMA), type Ⅰ collagen α1(COL1α1), COL3, and vimentin were detected by reverse transcription real-time fluorescence quantitative polymerase chain reaction(RT-qPCR). Superoxide dismutase(SOD) and malondialdehyde(MDA) kits were used to detect oxidative stress indicators in lung tissues and serum. The nuclear translocation of nuclear factor E2-related factor 2(Nrf2) protein was detected by immunofluorescence. The protein and mRNA expression levels of Nrf2, catalase(CAT), and heme oxygenase 1(HO-1) in lung tissues were detected by Western blot and RT-qPCR. Twelve chemical components were detected by UPLC-MS/MS. Animal experiments showed that MWYF could improve alveolar inflammation, collagen deposition, and fibrosis in PF mice, increase body weight of mice, and down-regulate the expression of fibrosis indexes such as HYP, α-SMA, COL1α1, COL3, fibronectin, and vimentin in lung tissues. In addition, MWYF could potentiate the activity of SOD in lung tissues and serum of PF mice, up-regulate the expression level of Nrf2, and promote its transfer to the nucleus, up-regulate the levels of downstream antioxidant target genes CAT and HO-1, and then reduce the accumulation of lipid metabolite MDA. In summary, MWYF can significantly improve the pathological damage and fibrosis of lung tissues in PF mice, and its mechanism may be related to the activation of the Nrf2 pathway to regulate oxidative stress.