Incidence of spontaneously occurring elevation of fasting blood glucose and its association with increased sarcopenia and exercise capacity deficit in aging C57BL/6J mice (LB818)

We have investigated the changes in skeletal muscle mass and exercise capacity with age, and the incidence and impact on muscle mass and exercise capacity of the spontaneous elevation of fasting blood glucose during old age, in male C57BL/6J mice. In mice ranging in age from 5 to 32 months, gastrocnemius muscle mass decreased significantly (↓27% at 32 months, ↓36% when normalized to body weight; ↓23% at 22 months normalized to body weight) compared to 5 months. In mice ranging in age from 7 to 31 months, exercise capacity (exercise to exhaustion on an incline treadmill protocol, expressed as total work) decreased significantly (↓65% at 31 months (↓23% at 22 months)) compared to 7 months. In 672 mice ranging in age from 18 to 26 months, peak incidence of elevated fasting blood glucose occurred at 21 months, at which age 53% of mice were below 110 mg glucose/dl blood, 33% of mice were between 110 and 140 mg/dl, and 14% were over 140 mg/dl. Comparing groups of 22 month-old mice with high (>170 mg/dl, n=9) or...