Orientin attenuates pulmonary fibrosis via TGF-β1/suppressor of mother against decapentaplegic 3 (Smad3) pathway.

La orientina reduce la fibrosis pulmonar mediante la vía de señalización TGF-β1/Smad3.

• Yijin Liu Department of Pharmacy, Liaoning University of Traditional Chinese Medicine Xinglin College, Shenyang, Liaoning Province, China. https://orcid.org/0009-0000-9374-5973
• Yao Lu Department of Thoracic Surgery, The Fourth Affiliated Hospital of China Medical University, Shenyang City, Liaoning Province, China. https://orcid.org/0009-0007-2749-1419

DOI: https://doi.org/10.54817/IC.v67n2a07

Keywords: Orientin, Pulmonary fibrosis, Fibroblasts, TGF-β1/Smad3 pathway

Abstract

Orientin, a natural flavonoid found in many medicinal plants, can improve lung injury through anti-inflammatory and antioxidant effects, but its role in pulmonary fibrosis (PF) remains unstudied. Human Fetal Lung 1 (HFL1) cells were stimulated with transforming growth factor-β1 (TGF-β1), and a single intratracheal bleomycin instillation in mice was used to establish a PF mouse model. Orientin, the TGF-β1/suppressor of mother against decapentaplegic 3 (Smad3) pathway agonist SRI-011381, and the inhibitor SB431542 were used for intervention. The proliferation and migration were evaluated using the Cell Counting Kit-8 (CCK-8), Edu staining (evaluated proliferative activity) and a scratch-healing assay. Fibers in HFL1 cells were detected by Sirius red staining. Inflammation and fibrosis in lung tissue were assessed by pathological staining and enzyme-linked immunosorbent assay (ELISA). PF and TGF-β1/Smad3 path- way protein expressions were evaluated by Western blot. Orientin significantly reduced TGF-β1, p-Smad3, alpha-smooth muscle actin (α-SMA), Collagen I, and matrix metallopeptidase (MMP)-2 levels. After Orientin treatment, the Edu pos- itive cells, cell proliferation and migration were significantly reduced, and the number of red-stained collagen fibers was significantly reduced. After Orientin treatment, alveolar cavity collapse, inflammatory cell infiltration, and collagen fiber hyperplasia of mice were alleviated, and the contents of Hydroxyproline (HYP) and inflammatory factors in the alveolar lavage fluid were significantly reduced. SRI-011381 attenuated the effect of Orientin on the intervention, and inflammation and fibrosis levels were markedly increased. SB431542 enhanced the intervention effect of Orientin. Orientin inhibited TGF-β1/Smad3 signaling, inhibited fibroblast-to-myofibroblast transition (FMT) and extracellular matrix (ECM) production, and alleviated inflammatory and fibrotic damage.

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