SMAD2 and liver dysplastic nodule: These results indicated that exosomes play a key role in the antifibrosis effects of mUC-MSC paracrine in DN by inhibiting MFT triggered by the TGF-β1/Smad2/3 signaling pathway and mesangial cell proliferation mediated by the PI3K/Akt and MAPK signaling pathways, and enhancing the expression of MMPs.