Immunohistochemical detection in mouse kidney tissues showed a significant increase in positive staining for TNF-α, TGF-β1, and α-SMA proteins in the glomeruli of mice in the DKD, Metrnl-/-, and Metrnl+/+ groups compared to that in the NC + NS group (P < 0.05). This evidence concerns the gene METRNL and diabetic kidney disease.