Further research indicated that in DKD rats, the therapeutic effects of TSF might at least be partially due to its anti-inflammatory action of downregulating tumor necrosis factor α and upregulating pro-inflammatory cytokine interleukin-10 [19], as well as its antifibrotic action of inhibiting expression of transforming growth factor beta 1 (TGF-β1) in renal tissue, enhancing the expression of matrix metallopeptidase 9 (MMP-9), and reducing the expression of collagen type IV [18]. Here, MMP9 is linked to diabetic kidney disease.