Abstract

The aim of this study was to investigate the effect of 2,3,4’,5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG) on vascular endothelial dysfunction in the type 2 diabetes rats, and the possible mechanisms. Sprague-Dawley rats were treated by high-fat diet and intraperitoneal injection of streptozotocin (40 mg/kg) to induce type 2 diabetes. TSG (60 or 120 mg/kg per day) was administered by oral gavage for 6 weeks. The vascular endothelial dysfunction was assessed using isolated aortic ring preparation. Fasting serum insulin (FINS), fasting blood glucose (FBG), malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-α) and free fatty acids (FFA) in serum were measured. The homeostasis model assessment-insulin resistance (HOMA-IR) was also calculated. The mRNA and protein expression of endothelial nitric oxide synthase (eNOS) and endothelin-1 (ET-1) in the aorta were tested by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western Blot. The results showed that TSG significantly decreased the levels of FBG, HOMA-IR, MDA, TNF-α and FFA and significantly increased the level of SOD. TSG also improved acetylcholine-induced endothelium-dependent relaxation. The expression of eNOS was significantly increased, whereas the expression of ET-1 was significantly decreased in aortas of diabetic rats with TSG treatment. These results demonstrate that TSG prevents vascular endothelial dysfunction in type 2 diabetes rats, and the mechanism may be related to its ability of anti-oxidation, anti-inflammation, improving insulin resistance, up-regulation of eNOS and down-regulation of ET-1.

Key words: 2,3,4’,5-Tetrahydroxystilbene2-O-β-D-glucoside, type 2 diabetes, endothelial dysfunction, endothelial nitric oxide synthase, endothelin-1.