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Oxytocin-mediated social enrichment promotes longer telomeres and novelty seeking

  1. Jamshid Faraji
  2. Mitra Karimi
  3. Nabiollah Soltanpour
  4. Alireza Moharrerie
  5. Zahra Rouhzadeh
  6. Hamid lotfi
  7. S Abedin Hosseini
  8. S Yaghoob Jafari
  9. Shabnam Roudaki
  10. Reza Moeeini  Is a corresponding author
  11. Gerlinde AS Metz  Is a corresponding author
  1. University of Lethbridge, Canada
  2. Golestan University of Medical Sciences, Iran
  3. Exceptional Education Organization, Iran
  4. Babol University of Medical Sciences, Iran
  5. Islamic Azad University, Iran
  6. Avicenna Institute of Neuroscience, Iran
Research Article
Cite this article as: eLife 2018;7:e40262 doi: 10.7554/eLife.40262
5 figures and 1 additional file


Housing conditions influence plasma OT and telomere length.

(A) Social enrichment altered plasma OT levels in socially raised animals. Social females showed higher OT concentration than social males (n = 21–23/group). (B) Social experience increased telomere length only in females (n = 23) when compared with standard rats (n = 27–28) and their social male counterparts (n = 31). Asterisks indicate significant differences: *p ≤ 0.05; **p ≤ 0.01; one-way ANOVA. Filled circles: mean OT concentrations in individual rats. Horizontal bars: mean OT concentrations in each group. pM: picoMolar, OT: oxytocin, Tel: telomere, bp: basepair.

Figure 1—source data 1

Housing conditions influence plasma OT and telomere length.

Figure 1—source data 2

Housing conditions influence plasma OT and telomere length.

Social experience alters novelty-seeking behaviour in the corridor field task (CFT).

(A and B) Illustration of the no-central and central-object CFT protocol along with samples of paths taken by rats in standard and social groups. (C and D) Social life affected novelty-seeking behaviour in a sexually dimorphic manner. Socially reared females (n = 22) explored the open and central zones more than their social male counterparts (n = 17) or standard group (n = 16 and 17). (E and F) The rate of changes (ROC) indicated the most profound impact on social females than any other group from no-central object to central-object versions of the CFT in the open and central zones. Also, a significant regression equation was found only in social females (n = 22) where OT concentration significantly predicts the exploration in the corridor and central zones (G) when central object was not presented. (H) Analysis of linear regression indicated significant regression equations for the time spent in open and central zones only in social females (n = 22) by which the increased plasma OT levels significantly predicted exploration time in CFT when the central object was presented. (I) The TL elongation, also, was significantly associated with an increase in plasma OT level only in social females (n = 22).

Figure 2—source data 1

Social experience alters novelty-seeking behaviour.

OT antagonist L-366,509 blocks the social experience phenotype in plasma OT concentration and telomere length.

(A and B) OT antagonist administration reduced plasma OT concentration in all OT ANT groups, except for standard OT ANT males (n = 10–13/group). Social control females displayed higher concentration of plasma OT than any other group. No difference was found between social control females and males. (C and D) OT antagonist L-366,509 reduced telomere length in social females. Asterisks indicate significant differences: *p ≤ 0.05; **p ≤ 0.01; one-way ANOVA. Filled circles: mean OT concentrations in individual rats. Horizontal bars: mean OT concentrations in each group. ANT: antagonist, bp: basepair, OT: oxytocin, pM: picoMolar, Tel: telomere.

Figure 3—source data 1

OT antagonist blocks phenotype.

Figure 3—source data 2

OT antagonost blocks social experience phenotype.

Behavioural consequences of the administration of OT antagonist L-366,509 in the corridor field task (CFT).

(A and B) The OT antagonist affected novelty-seeking behaviour in all zones of the no-central object CFT (standard: n = 28; social: n = 27). (C and D) The OT antagonist had a significant impact on the social females’ exploration in the central-object CFT. Novelty-seeking behaviour in socially raised females was more influenced by reduced OT levels than any other group (standard: n = 27; social: n = 27). (E–H) Rate of changes (ROC) within no-central and central-object CFT in response to OT antagonist. Note that social OT ANT females experienced the fewest changes in novelty-seeking behaviour from no-central object to central-object versions of the CFT. Asterisk indicates significant differences: p ≤ 0.05; MANOVA. Symbols denote comparisons: social control females: * relative to standard control females, # relative to standard OT ANT females, $ relative to social OT ANT females; social control males: * relative to standard control males, # relative to standard OT ANT males. Error bars show ± SEM. OT: oxytocin, ANT: antagonist.

Figure 4—source data 1

Behavioural consequences of OT antagonist.

Representation of the experimental design and hypothetical mechanisms of social experience in rats.

Male and female rats were raised in either (a) standard- or (b) social-housing units for 84–90 d. (b1) Prolonged social housing (b2) increased telomere length in females (TL) while enhancing plasma oxytocin (OT) in both sexes. Novelty-seeking behaviour in females more than males was responsive to social housing. (b3) Higher OT levels amplify social bonding and interaction through enhanced sociality. (c) Social interaction modulates novelty-seeking behaviours, OT, and TL along with HPA axis activity as a function of sex hormone status. Other hypothetical mechanisms to modulate social experience-dependent behaviour and neuroplasticity may include neurotrophic factors, such as brain-derived neurotrophic factor (BDNF).


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