title: A high fat diet-induced decrease in hippocampal newly-born neurons of male mice is exacerbated by mild psychological stress using a Communication Box.
abstract: Obese persons have a higher incidence of depression than healthy-weight persons. Several studies indicated that the exposure to a high fat diet (HFD) results in a decrease in hippocampal neurogenesis, which leads to higher stress response and stress-induced depression. Although stress is a risk factor for obesity and depression, no studies to date have investigated the effect of stress on the hippocampal neurogenesis of HFD-induced obese animals. The aim of this study was to elucidate whether or not obese HFD-fed mice are vulnerable to stress-induced depression by investigating hippocampal neurogenesis.
  
  
  
  Sixty-four male ICR mice (four weeks of age) were fed a control (N=24) or 45%HFD (N=40) for seven weeks. Of the HFD-fed group, twenty-four mice met the criteria for "diet-induced obesity". The animals were then exposed to three consecutive days of psychological stress using a Communication Box. Half were sacrificed to evaluate the physiological changes, and the other half were perfused to quantify hippocampal neuroblasts/immature neurons by the estimation of doublecortin-immunopositive cells.
  
  
  
  In the HFD-fed mice, psychological stress resulted in increases in caloric intake and visceral adipose tissue and a significant decrease in doublecortin-positive cells in the dentate gyrus; however, no such differences were found in the control diet-fed group. Limitations Further study using other neurogenic markers to assess the stage-specific changes in hippocampal neurogenesis will be required CONCLUSIONS: Our findings suggest that an HFD-induced decrease in hippocampal newly-born neurons leads to stress vulnerability, which may contribute to a high risk of stress-induced depression for obese persons.
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan. Electronic address: ymurata@fukuoka-u.ac.jp.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Murata
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
authors.forename: Yukiyasu
authors.initials: Y
authors.lastname: Narisawa
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
authors.forename: Rima
authors.initials: R
authors.lastname: Shimono
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
authors.forename: Hiraku
authors.initials: H
authors.lastname: Ohmori
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Mori
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ohe
authors.affiliation: Faculty of Neurology and Psychiatry, Mito Hospital, 4-1-1, Shime-Higashi, Shime-Machi, Kasuya-Gun, Fukuoka 811-2243, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Mine
authors.affiliation: Department of Pharmacotherapeutics, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1, Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.
authors.forename: Munechika
authors.initials: M
authors.lastname: Enjoji
mesh_terms: D000818:Animals; D001835:Body Weight / Q000502:physiology; D059305:Diet, High-Fat; D005260:Female; D006624:Hippocampus / Q000166:cytology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D055495:Neurogenesis / Q000502:physiology*; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D009765:Obesity / Q000503:physiopathology*; D011247:Pregnancy; D013315:Stress, Psychological / Q000503:physiopathology*
keywords: Communication Box; Depression; High fat diet; Hippocampal neurogenesis; Obesity; Psychological stress; Stress vulnerability