title: Beneficial effects of enriched environment on behaviors were correlated with decreased estrogen and increased BDNF in the hippocampus of male mice.
abstract: OBJECTIVE
  Previous studies reported that environmental enrichment might induce various beneficial effects in the central nervous system. However, the effect of environmental factors on endogenous estrogen level was not investigated. The present study was designed to examine the effect of enriched environment on endogenous estrogen in hippocampus and behavioral outcomes.
  
  
  METHODS
  Behavioural measurements, including open field, elevated plus maze and Morris water maze, were used to evaluate anxiety and learning and memory of the male C57BL/6J mice that were housed in enriched environment for five months. In addition, the estrogen and brain-derived neurotrophic factor (BDNF) expression in the hippocampus were measured.
  
  
  RESULTS
  We found that environmental enrichment decreased anxiety-like behaviors and facilitated spatial learning and memory in male C57BL/6J mice. In addition, the mice raised in enriched environment showed decreased endogenous estrogen levels both in the hippocampus and plasma compared to controls. Furthermore, our results indicated that environmental enrichment up-regulated BDNF mRNA expression level in the hippocampus.
  
  
  CONCLUSIONS
  In conclusion, environmental enrichment decreased anxiety-like behaviors and facilitated spatial learning and memory in male C57BL/6J mice. Lastly, environmental enrichment up-regulated BDNF mRNA expression level in the hippocampus and decreased plasma estrogen level. The possible mechanism remained to be determined.
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Fan-Tao
authors.initials: FT
authors.lastname: Meng
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Rong-Jun
authors.initials: RJ
authors.lastname: Ni
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Fang
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Li-Feng
authors.initials: LF
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: CAS Key Laboratory of Brain Function and Diseases, School of Life Science, University of Science and Technology of China, Hefei, Anhui, China.
authors.forename: Ya-Jing
authors.initials: YJ
authors.lastname: Liu
mesh_terms: D000818:Animals; D001007:Anxiety; D001522:Behavior, Animal; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics* / Q000378:metabolism; D004958:Estradiol / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D018782:Maze Learning; D008568:Memory; D051379:Mice; D012931:Social Environment
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D004958:Estradiol