MMP9 and renal fibrosis: Further,MMP-9 was reported to promote EMT and subsequent tubulointerstitial collagen accumulation66–68.The current study showed a sharp upregulation of MMP-9 and MMP-13 in diabetic kidney, which was found to be involved in excessive ECM accumulation and renal fibrosis, corroborating the previous findings1,4,25,69,70.