Both endurance- and resistance-type exercise prevents neurodegeneration and cognitive decline in mice with impaired glucose tolerance

The purpose of this study was to investigate the effects of different types of exercise training on neurodegeneration and cognitive function in mice with impaired glucose tolerance (IGT). Thirty-six male C57BL/6 mice were randomly assigned to the control (CO, n = 9) and impaired glucose tolerance (IGT, n = 27) groups. The IGT group consumed 45% high fat diet for 4 weeks and received 40 mg/kg of streptozotocin twice in the lower abdomen to induce IGT. After the IGT induction period, the IGT group was subdivided into IGT + sedentary (IGT, n = 9), IGT + endurance exercise (IGTE, n = 9), and IGT + resistance exercise (IGTR, n = 9). The IGTE and IGTR groups performed treadmill and ladder climbing exercises 5 times per week for 8 weeks, respectively. Fasting glucose and glycated hemoglobin (HbA1c) levels were significantly higher in IGT group than in CO, IGTE, and IGTR groups ( p < 0.05). HOMA-IR was significantly higher in IGT group than CO group ( p < 0.05). Hippocampal catalase (CAT) was significantly lower in IGT group than in CO group ( p < 0.05), while beta-amyloid (Aβ) was significantly higher in IGT group than in CO group ( p < 0.05). Hippocampal tau was significantly higher in IGT group than in CO, IGTE, and IGTR groups ( p < 0.05). The Y-maze test performance for cognitive function was significantly lower in IGT group than in CO, IGTE, and IGTR groups ( p <0.05). These results suggest that IGT induces neurodegeneration and negatively affects cognitive function, while regular exercise may be effective in alleviating neurodegeneration and cognitive decline regardless of exercise type.