TGFB1 and diabetes mellitus: Regarding the effects of exosomes on renal fibrosis induced by diabetes, repeated injection of MSC-derived exosomes in Group IV caused a significant decrease in the immunoexpression of TGF-β1 and collagen fiber deposition between glomeruli and tubules of renal samples stained by Masson’s trichrome, and these findings were confirmed by a significant decrease in protein expression of TGF-β and fibronectin by Western blot.