Based on the fact that glucosamine reduced the accumulation of extracellular matrix and expression of fibronectin in the glomeruli, but the transcriptional gene expression of extracellular components and inflammatory factors were not changed upon glucosamine treatment, we examined the protein expression of different markers for renal fibrosis such as fibronectin, collagen, connective tissue growth factor (CTGF), and α-smooth muscle actin (α-SMA) using immunoblotting (Figure 4). Here, FN1 is linked to renal fibrosis.