Seasonal variation in telomere length of a hibernating rodent

Abstract

Small hibernating rodents have greater maximum lifespans and hence appear to age more slowly than similar-sized non-hibernators. We tested for a direct effect of hibernation on somatic maintenance and ageing by measuring seasonal changes in relative telomere length (RTL) in the edible dormouse Glis glis. Average RTL in our population did not change significantly over the hibernation season, and a regression model explaining individual variation in post-hibernation RTL suggested a significant negative effect of the reduction in body mass over the inactive hibernation period (an index of time spent euthermic), supporting the idea that torpor slows ageing. Over the active season, RTL on average decreased in subadults but increased in adults, supporting previous findings of greater telomere shortening at younger ages. Telomere length increase might also have been associated with reproduction, which occurred only in adults. Our study reveals how seasonal changes in physiological state influence the progress of life-history traits, such as somatic maintenance and ageing, in a small hibernating rodent.

Late-born intermittently fasted juvenile garden dormice use torpor to grow and fatten prior to hibernation: consequences for ageing processes

“…Indeed, changes in RTL result from a balance between the processes of telomere shortening and lengthening via telomerase activity [52]. Similar findings have been reported in edible dormice (G. glis) [12]. The authors found that sub-adult dormice increase rspb.royalsocietypublishing.org Proc.…”

“…In the hibernating edible dormouse (Glis glis), the rate of decrease in RTL was positively correlated with overwinter body mass loss, which represents an index of the number of periodic arousals, i.e. the regular phases of rewarming that interrupt prolonged torpor in all hibernators, or the time spent in euthermy, in hibernating edible dormice [12]. Hence, ageing processes are expected to occur mainly during torpor arousals, i.e.…”

“…Opportunistic use of torpor bouts, interspaced by daylong active phases, is associated with the slowing of age-related processes [10]. Conversely, periodically rewarming from deep torpor and staying euthermic for only several hours during months of winter hibernation seems to impact negatively on physiological ageing mechanisms [12].…”

“…processes of rewarming from torpid to euthermic T b , and the subsequent inter-bout euthermy (IBE), i.e. the time spent euthermic between two torpor bouts (starting at the end of the rewarming process and ending at the onset of the entrance into the next torpor bout), phases of high levels of MR and therefore potential for oxidative stress [10,12]. Opportunistic use of torpor bouts, interspaced by daylong active phases, is associated with the slowing of age-related processes [10].…”

Telomeres are elongated in older individuals in a hibernating rodent, the edible dormouse (Glis glis)

“…It is also known that telomere length is not only maintained but can also be increased by these mechanisms (in somatic and germline cells). For instance, in two species of hibernating dormice, telomere length is shortened over the hibernation season during bouts of rewarming121314, which are associated with increased oxidative stress1516. However, for adult edible dormice it was shown that telomeres are restored and even increase in length during the summer active season1214.…”