WNT4 and renal fibrosis: Since the conversion of epithelial cells to cells with mesenchymal features has been recognized as one of the crucial causes of renal fibrosis in DN, and existing treatments cannot control the progression of DKD satisfactorily, we aimed to explore the changes in the immunohistochemical expression of EMT-related factors Snail, Wnt4, and Notch2 in the renal cortex structures of diabetic rats during ageing, which could help to elucidate their impact on DN development and may serve in the design of new treatment modalities for this condition.