FN1 and renal fibrosis: Histopathologically, PAS-staining and immunohistochemistry also demonstrated that treatment with SIS3 on the established db/db mice resulted in inhibition of progressive T2DN by significantly suppressing the glomerular matrix expansion and progressive renal fibrosis such as a marked accumulation of collagen I, IV, FN, and α-SMA+ myofibroblasts (Figure 5A-F).