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Front Behav Neurosci. 2018 Jul 17;12:145. doi: 10.3389/fnbeh.2018.00145. eCollection 2018.

Post-weaning Environmental Enrichment in Male CD-1 Mice: Impact on Social Behaviors, Corticosterone Levels and Prefrontal Cytokine Expression in Adulthood.

Frontiers in behavioral neuroscience

Robyn Jane McQuaid, Roderick Dunn, Shlomit Jacobson-Pick, Hymie Anisman, Marie-Claude Audet

Affiliations

  1. Institute of Mental Health Research, Royal Ottawa Mental Health Centre, Ottawa, ON, Canada.
  2. Department of Neuroscience, Carleton University, Ottawa, ON, Canada.
  3. School of Nutrition Sciences, University of Ottawa, Ottawa, ON, Canada.

PMID: 30065637 PMCID: PMC6056618 DOI: 10.3389/fnbeh.2018.00145

Abstract

Environmental enrichment is typically associated with enhanced well-being, improved cognitive function and stress resilience. However, in some instances grouping adult male mice in enriched conditions promoted a stressful environment, which resulted in elevated endocrine, monoamine and inflammatory outcomes in response to subsequent stressor exposure. The current investigation examined whether raising male mice in an enriched environment (EE) would modulate social and anxiety-like behaviors in early adulthood and influence brain expression of pro-inflammatory cytokines and brain-derived neurotrophic factor (BDNF). Immediately after weaning (postnatal day [PD] 21), CD-1 male mice were housed with their siblings (3/cage) for 6 weeks in an EE or a standard (SE) environment. Body weights and aggressive interactions were monitored weekly. Social avoidance behaviors in the social interaction test and anxiety-like behaviors in the elevated-plus maze were examined in early adulthood. Ninety minutes following the behavioral tests, mice were sacrificed and a blood sample and the prefrontal cortex (PFC) were collected for the determination of plasma corticosterone levels as well as cytokine and BDNF mRNA expression. Mice raised in an EE exhibited more wounds and gained less weight than mice housed in a SE. Enriched mice also spent a greater amount of time in proximity of a social target in the social interaction test and made fewer transitions into the closed arms of the elevated-plus maze. Interestingly, the elevated plasma corticosterone and upregulated prefrontal interleukin (IL)-1β expression observed after the social interaction test among the SE mice were not apparent among those housed in an EE. Enrichment also increased prefrontal BDNF expression, especially among mice that experienced the social interaction test. These results suggest that although raising male mice in an EE may elicit aggressive interactions between sibling cage-mates (as indicated by a high number of wounds), this environment also enhances social behaviors and limits the corticosterone and cytokine impacts of mild social stressors encountered in early adulthood.

Keywords: PFC; aggression; cytokines; enrichment; mice; stress resilience

References

  1. Behav Genet. 1999 Jan;29(1):41-6 - PubMed
  2. Nat Commun. 2018 Jan 19;9(1):298 - PubMed
  3. Neural Regen Res. 2015 Oct;10(10):1545-7 - PubMed
  4. Int J Neuropsychopharmacol. 2011 Apr;14(3):303-17 - PubMed
  5. Front Behav Neurosci. 2010 Aug 23;4:null - PubMed
  6. Front Mol Neurosci. 2016 Aug 03;9:62 - PubMed
  7. PLoS One. 2013;8(1):e54811 - PubMed
  8. Brain Behav Immun. 2017 Nov;66:45-55 - PubMed
  9. Transl Psychiatry. 2016 Jul 12;6(7):e854 - PubMed
  10. Physiol Behav. 1999 Dec 1-15;68(1-2):47-53 - PubMed
  11. Methods. 2001 Dec;25(4):402-8 - PubMed
  12. Prog Neuropsychopharmacol Biol Psychiatry. 2017 Jul 3;77:65-74 - PubMed
  13. PLoS One. 2017 Jan 20;12(1):e0170317 - PubMed
  14. Brain Behav Immun. 2012 Aug;26(6):1006-16 - PubMed
  15. Int J Dev Neurosci. 2018 Jun;67:19-32 - PubMed
  16. Brain Behav Immun. 2012 Mar;26(3):500-10 - PubMed
  17. Acta Neuropathol Commun. 2013 Sep 06;1:57 - PubMed
  18. Brain Behav Immun. 2011 Aug;25(6):1197-205 - PubMed
  19. Nat Protoc. 2008;3(6):1101-8 - PubMed
  20. Neurobiol Learn Mem. 2007 Jul;88(1):1-10 - PubMed
  21. Adv Exp Med Biol. 2017;977:175-181 - PubMed
  22. Behav Brain Res. 2013 Sep 1;252:49-57 - PubMed
  23. Neurobiol Stress. 2016 Nov 27;6:14-21 - PubMed
  24. Dev Psychopathol. 2001 Summer;13(3):419-49 - PubMed
  25. Neurosci Lett. 2011 Jan 7;487(2):250-4 - PubMed
  26. Behav Brain Res. 2016 Nov 1;314:215-25 - PubMed
  27. Psychoneuroendocrinology. 2015 Jul;57:72-83 - PubMed
  28. Physiol Behav. 2001 Oct;74(3):313-20 - PubMed
  29. Neuropediatrics. 2015 Feb;46(1):37-43 - PubMed
  30. Mol Psychiatry. 2010 Dec;15(12):1152-63 - PubMed
  31. Sci Rep. 2016 Jun 16;6:28182 - PubMed
  32. Physiol Behav. 2016 May 1;158:6-17 - PubMed
  33. Neuropharmacology. 2017 May 1;117:219-226 - PubMed
  34. Psychoneuroendocrinology. 2013 Jul;38(7):987-96 - PubMed
  35. Stress. 2012 May;15(3):354-60 - PubMed
  36. Brain Res Mol Brain Res. 2005 Jun 13;137(1-2):184-92 - PubMed
  37. Science. 2006 Feb 10;311(5762):864-8 - PubMed
  38. Behav Brain Res. 2018 Apr 16;342:43-50 - PubMed
  39. Anesthesiology. 2015 Jul;123(1):160-70 - PubMed
  40. Int J Neuropsychopharmacol. 2013 Mar;16(2):351-63 - PubMed
  41. Pharmacol Biochem Behav. 2002 Aug;73(1):193-207 - PubMed
  42. Lab Anim. 2003 Oct;37(4):300-13 - PubMed
  43. Hippocampus. 2015 Jan;25(1):1-15 - PubMed
  44. Horm Behav. 2013 Mar;63(3):503-9 - PubMed
  45. Horm Behav. 2003 Feb;43(2):281-92 - PubMed

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