Dense fibrosis of the glomerular microenvironment, particularly mesangial cells, is a hallmark of DKD, and the fibrosis of mesangial cells is closely associated with activation of the TGF-β1 signaling pathway, which promotes fibroblast activation and the abnormal synthesis of fibrotic matrix in mesangial cells [50]. Here, TGFB1 is linked to diabetic kidney disease.