TGFB1 and liver dysplastic nodule: In addition to inhibiting the TGF-β1/Smad3 signaling pathway by reducing the phosphorylation of Smad2/3, oral administration of Cortex eucommiae also inhibited the expression of TGF-β and CTGF (key mediators of RF) in Wistar rats with STZ-induced DN, thereby decreasing the levels of blood urea nitrogen (BUN) and serum creatinine (SCr) and ameliorating RF (Niu et al., 2016).