Meeting Abstract
Hibernation is a strategy used by some mammals to survive in the face of resource scarcity and is thought to confer increased longevity. However, reactive oxygen species (ROS) released in some tissues during periodic rewarmings may induce oxidative damage and accelerate cellular aging, which presents a life-history trade-off in hibernators. Telomeres, or the dynamic end-caps of chromosomes, can shorten in the presence of ROS, and an individual’s telomere length may reflect the degree of accrued oxidative damage. The objective of this study was to determine telomere length dynamics throughout the hibernation season in arctic ground squirrels (Urocitellus parryii). We hypothesized that telomere shortening would be most pronounced in tissues that support arousal episodes. DNA was extracted from liver, heart, and brown adipose tissue (BAT) of 46 individuals sampled either at the middle or end of hibernation. qPCR was used to determine relative telomere length (RTL) for each tissue. Sex or age (juvenile vs. adult) did not affect telomere length in any tissue measured. In juvenile females, RTL in BAT was significantly shorter at late hibernation than at mid-hibernation, whereas RTL in liver and heart were not different between hibernation stages. BAT is the organ that generates heat during periodic rewarmings throughout hibernation. With BAT-associated thermogenesis comes a substantial increase in ROS, which may be shortening telomeres in this tissue. This study uses a multiple-tissue approach to address the life-history trade-off between longevity and cellular aging in a hibernating mammal.
