Effects of diet quality on vulnerability to mild subchronic social defeat stress in mice

Abstract

Objectives: The chronic social defeat stress (CSDS) mouse model is a potentially useful system for understanding stress responses to social environments. We previously developed a mouse model of subchronic and mild social defeat stress (sCSDS) that exhibits increased body weight gain and food intake following polydipsia-like features. sCSDS mice also show avoidance behavior in a social interaction test. In this study, we examined the effects of diet quality on susceptibility to sCSDS by feeding these mice semi- and non-purified diets.

Methods: Male C57BL/6J (B6; n = 82) mice were exposed to sCSDS using male ICR mice. The B6 mice were divided into four test groups: semi-purified pellet diet + sCSDS, non-purified pellet diet + sCSDS, semi-purified diet + control (no sCSDS), and non-purified diet + control.

Results: Although increased body weight, and food and water intake following sCSDS exposure were consistently observed in the groups that were fed semi- and non-purified diets, social avoidance behavior was influenced by food type (i.e., sCSDS mice fed semi-purified diet showed the greatest social avoidance behavior). In addition, the rates of stress susceptibility were estimated at 73.9 and 34.8% in sCSDS mice fed semi-purified and non-purified diets, respectively (P < 0.05). For comparison, the susceptible-like phenotype rates were estimated at 12.5 and 8.3% in healthy control mice fed semi-purified and non-purified diets, respectively.

Discussion: These results suggest that diet quality affects the vulnerability of mice to social defeat stress.

Keywords:

• Diet
• Mouse
• Psychological stress
• Resilience
• Social behavior
• Susceptible
• Vulnerability

Disclaimer statements

Contributors TG and AT designed the study. TG and YK conducted and analyzed the animal experiments. TG and AT wrote this paper.

Funding This research was supported in part by an Ibaraki University Cooperation between Agriculture and Medical Science (IUCAM) (The MEXT, Japan), the Research Project on the Development of Agricultural Products and Foods with Health-promoting benefits (NARO) (The MAFF, Japan), and Council for Science, Technology, and Innovation (CSTI), Cross-ministerial Strategic Innovation Promotion Program (SIP), ‘Technologies for creating next-generation agriculture, forestry and fisheries’ (Bio-oriented Technology Research Advancement Institution, NARO) (The Cabinet Office, Japan).

Conflicts of interest None.

Ethics approval This study was approved by the Animal Care and Use Committee of Ibaraki University and was in accordance with the guidelines published by the Ministry of Education Culture, Sports, Science, and Technology (MEXT), Japan (Notification No. 71).