Puerarin Reduces the Levels of AGE-Modified Proteins in Serum and Retinal Tissues to Improve the Retinal Damage in Diabetic Rats

The objective was to analyze the impact of puerarin on the AGEs (Advanced glycated endproducts) modified proteins in serum and retinal tissues of diabetic rats. SD rats were randomly divided into the normal control group, the diabetic group and the puerarin intervention group. The rats from diabetic and puerarin intervention group were given 2% streptozotocin (55 mg/kg) via single intraperitoneal injection. Then the rats from puerarin intervention group were orally administered puerarin solution (80 mg/kg/day). The total AGEs-modified protein concentrations in rat serum and retinal tissues were detected. The expressional levels of AGEs-modified proteins in serum were analyzed with SDS-PAGE/Western and 2-DE/Western. The differently expressed AGEs-modified proteins were identified by MALDI-TOFMS. The total AGEs-modified protein concentrations in the serum and retinal tissues in diabetic group and puerarin intervention group were significantly higher compared to control group (P < 0.05). AGEs-modified protein concentrations in the serum and retinal tissues in rats from puerarin intervention group were significantly decreased compared to diabetic rats (P < 0.05). Furthermore, compared with the control group, the retinal tissues in diabetic rats revealed apparent pathological changes, while the changes observed in puerarin intervention group were much more limited compared to diabetic group. Five differently expressional AGEs-modified proteins by SDS-PAGE/Western, and ten differently expressional AGEs-modified proteins by 2-DE/Western were separated from serum. Moreover, four types of serum AGEs-modified proteins were identified, including T-kininogen, complement C3, serotransferrin, and albumin. Puerarin may inhibit the expressional levels of serum AGEs modified proteins and decrease the accumulation of AGEs modified proteins in the retina, thus improving the retinal damage in diabetes.