-Inhibited the Mesangial cell MMCs proliferation-Arrested cells in phase G2-Down-expressed let-7a in both diabetic nephropathy rats and MMCs-Affected the expressions of collagen IV and fibronectin through upregulating let-7a in MMCs-Inhibited the TGF-β1/smads signaling activation by upregulating let-7a⇒ Naringenin ameliorates kidney injuries by regulating let-7a/TGFBR1 signaling. The gene discussed is FN1; the disease is diabetic kidney disease.