MMP9 and Diffuse mesangial sclerosis: Mesangial sclerosis and thickening of basement membranes of various renal components can be attributed to reduced activities of matrix metalloproteinases (e.g., MMP2 and MMP9) and glomerular proteinases (e.g., cathepsin B and collagenase), as well as overproduction and deposition of glycogen in the renal tubules and Bowman's capsules of diabetic rats [59,60].