REN and diabetic kidney disease: The intracellular molecular pathways are believed related to mesangial cell proliferation and fibrosis including the activation of renin-angiotensin system, transforming growth factor β1 (TGFβ1), monocyte chemotactic protein-1, connective tissue growth factor (CTGF), and fibronectin (FN), etc. [22–25], which can effectively assess the extent of renal injury and timely guide the clinical treatment of DKD [26–29].