SMAD2 and Hepatic fibrosis: To investigate the underlying mechanism of the effect of hFSSC secretome on liver fibrosis, we performed the Western blot and RT-qPCR to analyze the expression of TGF-β1, Smad2, Smad3, Smad7, and Collagen I in HSCs, as it is one of the major effector cells in liver fibrosis.