Figure 5. Sex-specific effects of detrimental (HFD) and beneficial (rapamycin) factors on BA of NIH Swiss mice. Feeding HFD accelerates aging of NIH Swiss male mice whereas rapamycin counteracts this process. Projected biological age of individual mice (shown by circles) and mean BA for the group (black marker) were calculated from the corresponding FI value using the fitting model predictions. Red line designates chronological age of all mice at the time of testing (78 weeks). Data show that projected BA of all mice that received HFD (green circles) is significantly higher that their actual chronological age and mean BA age for control group on regular diet (62.7+13.3 and 96.4+8.8 weeks for RDW and HFDW groups respectively (p=0.03, Student’s t-test). Chronic administration of rapamycin reduces BA of males fed HFD to values characteristic for control group (from 96.4+8.8 to 71.5+9.6 weeks; p=0.04, Student’s t-test). No difference between groups was detected in female mice, in which BA was very close to their CA. Slight reduction in BA in rapamycin treated group from 71.8+7.8 to 62.6+7.0 weeks was not statistically significant (p=0.3 Student’s t-test).