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-beta/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, alpha-smooth muscle actin, transforming growth factor-beta 1, 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.