Objective: To evaluate the effect of oral vitamin D supplementation in early life on blood glucose, insulin content, diabetes incidence, and histomorphology in pancreatic islet induced by streptozotocin.
Methods: Three-week-old C57BL/6 mice were given either control diet (American Institute of Nutrition [AIN]-93G), or three different dose of vitamin D-supplemented diet. Nine weeks after dietary intervention, C57BL/6 mice were treated with streptozotocin i.p. for 5 consecutive days. After injection of STZ, The fasting blood glucose and diabetes incidence was tested once a week. The insulin content, histomorphology in pancreatic islets was conducted at the end of experiments.
Results: (1) Vitamin D supplementation in early life can decrease the fasting blood glucose values induced by STZ, and the decreases effect of high dose vitamin D-supplemented group is the most significant (P<0.01). (2) Vitamin D supplementation in early life can prevent diabetes incidence, and the decreases effect of high dose vitamin D-supplemented group is the most significant, fully suppress the onset of diabetes about four weeks later after injected by STZ (P<0.01). (3) As compared to the control group, insulin content in medium and high dose vitamin D-supplemented groups were significantly up-regulated after injection of STZ (P<0.05), and the effect of high dose vitamin D-supplemented group is the most significant. (4) The damage of pancreatic islets induced by STZ was clearly restored in medium and high dose vitamin D-supplemented groups, and effect of high dose vitamin D-supplemented group is the most significant.
Conclusion: Oral vitamin D supplementation in early life can decrease the fasting blood glucose values, prevent diabetes incidence, up-regulate insulin content, restored the damage of pancreatic islets induced by STZ, and effects of high dose vitamin D-supplementde group are all the most significant.