Astragalus polysaccharides protect renal function and affect the TGF-β/Smad signaling pathway in streptozotocin-induced diabetic rats

OBJECTIVES: The objective was to observe the effects of Astragalus polysaccharides on diabetes and on regulation of the TGF-β/Smad signaling pathway. METHODS: A type 2 diabetic rat model was established with a high-fat diet in combination with low-dose streptozotocin (35 mg/kg). Astragalus polysaccharides were applied as treatment intervention and changes in blood glucose and kidney morphology and function were assessed. RESULTS: Eight weeks after model establishment, kidney weight as a proportion of total weight (KW/TW) in the high-, medium-, and low-dose Astragalus polysaccharide groups was significantly lower than that in the model group, and the KW/TW value gradually decreased with increasing dose of polysaccharides in each treatment group. Fasting blood glucose in the low- and medium-dose Astragalus polysaccharide groups was numerically lower than that in the model group and fasting blood glucose in rats in the high-dose group was significantly lower than that in the model group. Levels of 24-hour urinary microalbumin, creatinine, blood urea nitrogen, collagens I, III, and IV, α-smooth muscle actin, transforming growth factor-β1, and Smad3 in Astragalus polysaccharide groups (all doses) were significantly lower than those in the model group. CONCLUSIONS: Astragalus polysaccharide significantly improved blood glucose and protected kidney function in a rat diabetes model.