The Therapeutical Effects Of Antioxidants On Type 2 Diabetes

Type 2 diabetes mellitus is characterized by resistance of peripheral tissue to insulin and a relative deficiency of insulin secretion. At present, it has become as the third one just followed cancer and cardiovascular diseases among the significant non-communicable diseases, which mostly threaten people’s health. This research used a type 2 diabetes animal model to explore whether or not different antioxidants such as red yeast rice and astaxanthin could be used as new supplements for improving symptom of type 2 diabetes. At the same time, this research also tried to discuss possible molecular mechanisms underlying the improvement of type 2 diabetes by these two substances.At first, Wistar rats were fed by high-fat-high-sucrose diet (HD) for 4 weeks, 72 hours after one ip-injection of STZ (40mg/kg body weight), their blood glucose was tested by tail vein. The induced type 2 diabetic rats were fed by basic diet (BD) supplemented with three different concentrations of red yeast rice (0.5g/kg BD, 1g/kg BD, 2g/kg BD) and metformin for 4 weeks, respectively. Metformin served as the positive control. Metformin and red yeast rice showed their strong ability in lowering blood glucose levels.Then, astaxanthin was analyzed for the possible treatment of type 2 diabetic rats. Type 2 diabetic rats were fed by BD supplemented with three different concentrations of astaxanthin (15g/kg BD, 30g/kg BD, 50g/kg BD). After three weeks, blood glucose levels were significantly reduced by all the treatments of astaxanthin. Moreover, this glucose-lowering effect was exhibited in a dose-dependent manner, showing that the greatest effect at the level of astaxanthin 50g/kg BD.Furthermore, under the foundation of previous research, red yeast rice and astaxanthin were combined to feed the type 2 diabetic rats for dicussing their possible combinative therapeutical effects on type 2 diabetes. As a result, we found that the combination of red yeast rice and astaxanthin has much stronger ability in lowering blood glucose levels than any one of themselves. In addition, we also found that pure lovastatin (Monacolin K) also could decrease the blood glucose level, indicating that the active ingredient in red yeast rice to reduce the blood glucose level may be lovastatin (Monacolin K).In order to know the possible mechanism of red yeast rice and astaxanthin, the expression levels of several genes closely related to type 2 diabetes were analyzed. Red yeast rice and astaxanthin could improve the expression levels these seleted genes in liver, muscle and adipose tissues, which were greatly altered by type 2 diabetes. These results suggested that red yeast rice and astaxanthin may ameliorate symptoms of type 2 diabetes by improving the transcription of some genes, which deeply involve in glucose metabolism and lipid metabolism.In conclusion, the results obtained in the present study manifested the potential functions, the effective concentrations and possible molecular mechanisms of red yeast rice and astaxanthin in treating type 2 diabetes. Therefore, this study might provide some insights into therapeutical functions of these antioxidants on type 2 diabetes, and might lay the foundation for futher study.