Previous study has revealed that infiltrated monocytes/macrophages release lysosomal enzymes, nitrous oxide, reactive oxygen intermediates and TGF-β, which have been reported to play an essential role in renal damage and the depletion of macrophage by irradiation decreased the gene expression of TGF-β and type IV collagen in the glomeruli of diabetic rats at 4 weeks after induction of diabetes, suggesting the pathological role of macrophages in the increased expression of ECM proteins [56,57]. Here, TGFB1 is linked to diabetes mellitus.