Treatment with 50 mg/kg−1 day−1 calycosin in male C57/BL6 mice can reduce myocardial fibrosis by directly inhibiting the transforming growth factor-beta receptor 1 (TGFBR1) pathway and down-regulating intracellular signal transducers Smad2/3 to suppress the proliferation and activation of cardiac fibroblasts as well as collagen and extracellular matrix deposition against myocardial fibrosis [36]. The gene discussed is SMAD2; the disease is Myocardial fibrosis.