Biochanin-A ameliorates pulmonary fibrosis by suppressing the TGF-β mediated EMT, myofibroblasts differentiation and collagen deposition in in vitro and in vivo systems

Background: Idiopathic Pulmonary Fibrosis (IPF) is a progressive inflammatory disorder driven by a fibrotic cascade of events such as epithelial to mesenchymal transition, extracellular matrix production and collagen formation in the lungs in a sequential manner. IPF incidences were raising rapidly across the world. FDA approved pirfenidone and nintedanib (tyrosine kinase inhibitors) are being used as a first-line treatment drugs for IPF, however, neither the quality of life nor survival rates have been improved because of patient noncompliance due to multiple side effects. Thus, the development of novel therapeutic approaches targeting TGF-β mediated cascade of fibrotic events is urgently needed to improve the survival of the patients suffering from devastating disease. Purpose: The aim of this study was to investigate and validate the anti-fibrotic properties of Biochanin-A (isoflavone) against TGF-β mediated fibrosis in in vitro, ex vivo, in vivo models and to determine the molecular mechanisms that mediate these anti-fibrotic effects. Methods: The therapeutic activity of BCA was determined in in vitro/ex vivo models. Cells were pre-treated with BCA and incubated in presence or absence of recombinant-TGF-β to stimulate the fibrotic cascade of events. Pulmonary fibrosis was developed by intratracheal administration of bleomycin in rats. BCA treatment was given for 14 days from post bleomycin instillation and then various investigations (collagen content, fibrosis gene/protein expression and histopathological changes) were performed to assess the anti-fibrotic activity of BCA. Results: In vitro/ex vivo (Primary normal, IPF cell line and primary IPF cells/ Precision cut mouse lung slices) experiments revealed that, BCA treatment significantly (p < 0.001) reduced the expression of TGF-β modulated fibrotic genes/protein expressions (including their functions) which are involved in the cascade of fibrotic events. BCA treatment significantly (p < 0.01) reduced the bleomycin-induced inflammatory cell-infiltration, inflammatory markers expression, collagen deposition and expression of fibrotic markers in lung tissues equivalent or better than pirfenidone treatment. In addition, BCA treatment significantly (p < 0.001) attenuated the TGF-β1/BLM-mediated increase of TGF-β/Smad2/3 phosphorylation and resulted in the reduction of pathological abnormalities in lung tissues determined by histopathology observations. Conclusion: Collectively, BCA treatment demonstrated the remarkable therapeutic effects on TGF-β/BLM mediated pulmonary fibrosis using IPF cells and rodent models. This current study may offer a novel treatment approach to halt and may be even rescue the devastating lung scarring of IPF.