The effects of the water-extraction of Astragali Radix and Lycopi herba on the Pathway of TGF‑smads‑UPP in a rat model of Diabetic Nephropathy

Background: Astragali Radix and Lycopi Herba were widely used in clinical practice for treating the diabetic nephropathy (DN), but their therapeutic mechanisms were not clear. Objective: To observe the effects of the water‑extraction of Astragali Radix and Lycopi Herba on the signaling pathway of TGF‑Smads‑UPP in streptozotocin (STZ)‑induced DN. Materials and Methods: Sprague- Dawley (SD) rats were randomly divided into the normal control (NC) group and the model group. The NC group was fed with a standard diet and the other five diabetic groups received a high‑fat diet. After 4 weeks, five diabetic groups were treated with STZ (30mg/kg i.p.). The NC group rats were treated with citrate buffer. Tail random blood glucose (RBG) was measured 72h later using a strip‑operated blood glucose sensor and monitored every 2 weeks until drug intervention. Rats with RBG levels less than 16.7mmol/L were excluded from the diabetic groups. At the end of 4 weeks after STZ injection, 24h microalbuminuria was collected and detected. The microalbuminuria was measured by radioimmunoassay (RIA). The blood glucose was tested using a blood glucose meter. The kidney was dissected from each SD rat. Proteins and mRNA of TGF‑β1, Smads and Smurf were tested by western‑blot and real‑time PCR analysis, and 26S proteasome activity was measured by an ELISA kit. Results: The water‑extraction of Astragali Radix and Lycopi Herba significantly lowered fasting glucose and urine albumin in diabetic rats through inhibition of TGF‑β1 mRNA and protein expression in the STZ‑induced diabetic rats, and regulation of the Smad3, Smad7, Smurf1, Smurf2 mRNA and protein expression, as well as elevated 26S proteasome activity to play control effect in DN. Conclusion: 0.9 g/ml water‑extraction of Astragali Radix and Lycopi Herba group has significant therapeutic effects on the STZ‑induced diabetic rats, and this regulation depends on TGF‑Smads‑UPP signaling pathway.