Abstract: Objective To investigate the protective effect of Pinocembrin (PB) on rat diabetic nephropathy (DN) and its associated mechanism. Methods SD rats in this study were divided into 5 groups including normal control ( group N, standard feed ) ,DN model group (group M ,high-sugar-fat food+ STZ 40 mg/kg), pinocembrin groups (the high dose group H :40 mg/kg.d, the low dose group L ,20 mg/kg.d, oral gavage), valsartan group (group V, 30 mg/kg.d, oral gavage) randomly. The end of 4th, 8th and 12th week after modeling were considered as time-points in this study. At each time point, the level of 24 hours urine protein (24 h TUP ), blood glucose (BG) were examined. The level of serum Ang II was determined by ELISA method. The renal pathological changes were evaluated by HE staining and PAS staining, and the expression of nuclear factor-kappa B (NF-κB) in the kidney was detected by immunohistochemical method. Results 1) The TG level in group H and group L were significantly lower than the data in group M (P＜0.01); 2) At the end of 4th, 8th and 12th week after treatment , the 24 h TUP level in group H , group L and group V were significantly lower than the data in group M (P＜0.01); 3) Compared with group M, The renal hypertrophy index in group H , group L and group V was significantly decreased (P<0.05); 4) Morphological evaluation: Kidneys of each DN group were characterized by glomerular hypertrophy and proliferation in different degree. The mesangial expansion index (MEI) of group H ,group L and group V decreased when compared for group M(P＜0.01); 5) The serum concentration of AngⅡ and the expression of NF-κB protein in group M was significantly higher than that in group N (P＜0.01) . Those data decreased markedly in group H ,group L and group V when compared with group M (P＜0.01). And those data were positively correlated, (P<0.001). Conclusions There is a protective effect of PB on rats DN, The possible mechanism is reducing the serum concentration of AngⅡ and expression of NF-κB protein in renal tissue possibly.

Key words: DN , pinocembrin , AngⅡ, NF-κB, mesangial expansion