Deficiency of FGF21 aggravated diabetes-induced inflammation, oxidative stress, and fibrotic effect. Western-blot assay revealed that diabetes, but not STZ significantly upregulated ICAM-1, TNF-α, and PAI-1 expression in the kidneys of C57BL/6J mice, which were further increased in FGF21-KO mice (Fig. 8A-C). This evidence concerns the gene FGF21 and diabetes mellitus.