FN1 and diabetic kidney disease: (5) Hyperglycemia can promote the secretion of fibronectin, type I collagen, type IV collagen, interleukin-6, interleukin-1β and tumor necrosis factor-α, resulting in oxidative stress, apoptosis, injury of renal tubular epithelial cells and glomerular and tubular fibrosis, and accelerate the occurrence and development of DKD.