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Objective:To investigate the renoprotective effects of DNL on nonenzymatic glycation and oxidative stress in the diabetic rat kidney. Methods:After a DM rat model was induced by streptozotocin. DM rats were randomly divided into these groups:diabetic control group, DNL low dose group, DNL moderate dose group, DNL high dose group and AG control group;in addition, set up a normal control group. Diabetic control group and normal control group were given water, administration for 12 weeks. Body weight,Urine volume,Food intake,Water intake,Kidney index,24h Urinary albumin,Serum gluc-ose, HbAlc, Serum urea, Creatinine, AGEs, Urine creatinine, renal total SOD,MDA, AGEs were measured. The PAS-stained sample was observed under light microscope and the ultrastructural morphology was observed by the electron microscope. RT-PCR was performed to determine the expressionof RAGE mRNA.Western blot was was performed to determine the protein expression of RAGE. Results:A DM rat model was successful-ly established. DNL moderate dose group and high dose group significantly decreased serum glucose and glycated hemoglobin levels(p< 0.05). The level of serum urea (p< 0.001) and 24h Urinary Albumin(p< 0.001) were significantly increased,and Ccr was significantly reduced(p< 0.001) in the DM rats compared with normal rats. But serum urea(p< 0.05) and 24h Urinary Albumin levels(p< 0.05) were significantly decreased and Ccr(p< 0.05) was significantly increased by DNL.The serum AGEs, renal AGEs and MDA levels of DM rats compared with normal rats were increased(p< 0.001),total SOD level was significantly decreased (p< 0.001);but DNL significantly increased total SOD level (p< 0.05) and decreased MDA level (p< 0.001)in DM rats,and dose-dependently reduced serum and renal AGEs levels. the kidney index of the DM rats were significantly higher than those of normal control group (P<0.01),but DNL significantly decreased the kidney index.(p< 0.05). Observing PAS stain by light microscopy and transmission electron microscopy scanning,the mesangium expansion and basement membrane thickness were significantly improved by DNL and AG.The expressions of RAGE mRNA and protein both significantly declined by the DNL and AG.Conclusion:DNL can reduce serum glucose,inhibit AGEs formation,down-regulate renal RAGE mRNA and protein expressions and inhibit oxidative stress, consequently delay the occurrence and development of DN.
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