Protective effects of combined micronutrients on islet β-cells of streptozotocin-induced diabetic mice

There is a tendency for the incidence of diabetes in a population to increase with an improvement in living standards. This would imply the involvement of nutritional factors in the development of diabetes, and so nutritional considerations could be a key aspect in the research and development of an effective remedy for diabetes. In this study, combined micronutrients (selenium, vitamin E, vanadium, and chromium) were orally supplemented to streptozotocin-induced diabetic mice. Results showed that combined micronutrients could decrease the high blood glucose levels (p<0.05 or p<0.01) of diabetic mice. The protective effects of combined micronutrients on structures of β-cells in pancreatic islets of diabetic mice were observed histopathologically and ultrastructurally. In addition, the supplementation of combined micronutrients increased insulin expression by β-cells in pancreatic islets of diabetic mice at both translational and transcriptional levels. The immune molecular mechanisms involved were preliminarily regarded as downregulation of the expression of pathogenic T-helper 1 lymphocyte (Th1) cytokine tumor necrosis factor-α (TNF-α) (p<0.01) along with upregulation of the expression of protective T-helper 2 lymphocyte Th2 cytokine interleukin 10 (IL-10) (p<0.01) which ameliorates the Th1/Th2 imbalance in diabetes. In conclusion, supplementation of combined micronutrients to diabetic mice could effectively improve disordered glucose metabolism, protect islet structures, and improve the function of β-cells in pancreatic islets, which are affected by differential regulation of the expression of Th1/Th2 cytokines involved in the pathogenesis of diabetes.