Objective: To compare the effects of long-term experimental stressors on blood glucose level and insulin secretion in the aged and young mice with diabetes-prone and to explore the mechanism.
Methods: Diabetes-prone was induced by streptozotocin (STZ) in 40 1.5-month-old mice and 40 15-month-old mice. The young and the aged STZ mice were divided randomly into the stress group and the control group, respectively. Each group contained 20 mice. Both the aged and the young stress mice were exposed to multiple stressors (restrain, rotation, crowding) for 6 weeks. Fasting blood glucose (FBG), fasting plasma insulin (FINS), pancreas lipid peroxidase (LPO) and the metabolic products of nitric oxide (NO2-, NO3-) levels and superoxide dismutase (SOD) activity were measured. The grade of insulitis in STZ mice was also evaluated.
Results: After 6-week stress, FBG level, pancreatic tissue LPO and NO2-, NO3- contents were significantly higher while FINS level and SOD activity lower in the aged stress mice than those in the youngs. The insulitis malignization in the aged stress group was severer than that in the young stress group. There were correlativities among the above variables.
Conclusion: The effects of long-term stress in promoting hyperglycemia exacerbating insulitis, and inhibiting insulin secretion are more significant in the aged STZ mice than in the young ones. This difference may result from the excessive NO and the peroxide injury to the pancreas.