Polydatin Alleviates Diabetes-Induced Hyposalivation through Anti-Glycation Activity in db/db Mouse

Polydatin (resveratrol-3-O-β-mono-D-glucoside) is a polyphenol that can be easily accessed from peanuts, grapes, and red wine, and is known to have antiglycation, antioxidant, and anti-inflammatory effects. Diabetes mellitus is a very common disease, and diabetic complications are very common complications. The dry mouth symptom is one of the most common oral complaints in patients with diabetes mellitus. Diabetes mellitus is thought to promote hyposalivation. In this study, we aimed to investigate the improvement effect of polydatin on diabetes-induced hyposalivation in db/db mouse model of type 2 diabetes. We examined salivary flow rate, TUNEL assay, PAS staining, and immunohistochemical staining for AGEs, RAGE, HMGB1, 8-OHdG, and AQP5 to evaluate the efficacy of polydatin in the submandibular salivary gland. Diabetic db/db mice had a decreased salivary flow rate and salivary gland weight. The salivary gland of the vehicle-treated db/db mice showed an increased apoptotic cell injury. The AGEs were highly accumulated, and its receptor, RAGE expression was also enhanced. Expressions of HMGB1, an oxidative cell damage marker, and 8-OHdG, an oxidative DNA damage marker, increased greatly. However, polydatin ameliorated this hypofunction of the salivary gland and inhibited diabetes-related salivary cell injury. Furthermore, polydatin improved mucin accumulation, which is used as a damage marker for salivary gland acinar cells, and decreased expression of water channel AQP5 was improved by polydatin. In conclusion, polydatin has a potent protective effect on diabetes-related salivary gland hypofunction through its antioxidant and anti-glycation activities, and its AQP5 upregulation. This result suggests the possibility of the use of polydatin as a therapeutic drug to improve hyposalivation caused by diabetes.