Abstract: Objective To explore the protectory effects of naringenin (NAR) on kidney as well as its effects on TGF-β1/smad signaling pathway in diabetic nephropathy rats. Methods Experimental rats were randomly assigned into diabetic nephropathy group and naringenin group. After rats were treated with naringenin for 6 weeks, the 24 h-urinary protein (24 h-UP), Creatinine clearance rate (Ccr) and kidney index (KI) were detected. Glomerular pathological changes and glomerular area(GA) were observed by HE-straning. Type Ⅳ collagen（Col4）、fibronectin（FN） were detected by real-time PCR and Western blot. TGF-β1，smad7，t-smad2 and p-smad2 were detected by Western blot. Results Compared with CON group, the 24 h-UP (P <0.01), KI (P <0.01) and GA (P <0.05) were increased, whereas Ccr (P <0.01) was declined in DN group, the mRNA and protein of Col4 and FN were increased, the protein of TGF-β1 and p-smad2 were increased and smad7 was decreased. Naringenin treatment could significantly attenuated the renal lesion, inhibited the expression of Col4，FN，TGF-β1 and p-smad2， improved the expression of smad7. Conclusion Naringenin ameliorates renal function, has marked protectory effects on kidneys in diabetic nephropathy, possibly through inhibited the activation of TGF-β1/smad and reduced the deposition of ECM proteins.

Key words: naringenin, ECM, TGF-β1/Smad signaling, diabetic nephropathy