Influence of aging on the behavioral phenotypes of C57BL/6J mice after social defeat

• Published in: PloS one Vol. 14; no. 9; p. e0222076
• Main Authors: Oizumi, Hiroaki, Kuriyama, Nae, Imamura, Sachiko, Tabuchi, Masahiro, Omiya, Yuji, Mizoguchi, Kazushige, Kobayashi, Hiroyuki
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 03.09.2019; Public Library of Science (PLoS)
• Subjects: Aging; Aging (Biology); Aging - pathology; Aging - physiology; Aging - psychology; Analysis; Animal behavior; Animal cognition; Animals; Anxiety; Anxiety - psychology; Avoidance; Avoidance behavior; Avoidance Learning; Behavior; Behavior, Animal; Biology and Life Sciences; Blood pressure; Body Weight; Brain research; Care and treatment; Depression (Mood disorder); Depression - psychology; Dopamine; Drinking; Elderly; Fear & phobias; Food Preferences - psychology; Health aspects; Hedonic response; House mouse; Laboratories; Male; Medical research; Medicine and Health Sciences; Mental depression; Mental disorders; Mice; Mice, Inbred C57BL; Middle age; Older people; People and Places; Phenotype; Phenotypes; Physical Sciences; Psychological aspects; Risk factors; Rodents; Social Behavior; Social factors; Social interactions; Social Sciences; Stress; Stress, Psychological; Sucrose; Sugar; Tumor necrosis factor-TNF; Water intake; Water intakes; Wildlife conservation; Young adults; Japan
• DOI: 10.1371/journal.pone.0222076
• ISSN: 1932-6203

Depression and anxiety are common psychiatric disorders that can occur throughout an individual's lifetime. Numerous pathways underlying the onset of these diseases have been identified in rodents using a social defeat stress protocol, whereby socially defeated individuals exhibit depression- and/or anxiety-like phenotypes that typically manifest as social avoidance behavior. However, most studies in this field have been conducted using young adult mice; therefore, information about social defeat stress-related behavioral phenotypes in older mice is limited. In this study, we exposed groups of young adult (8-16 weeks old) and aged (24 months old) C57BL/6J mice to mild social defeat stress by challenging them with aggressive CD1 mice while restricting the intensity of aggression to protect the animals from severe injuries. We then identified stress-induced behavioral changes and compared their expression between the age groups and with a non-defeated (non-stressed) control group. We found that the stressed mice in both age groups exhibited similar reduced social interactions that were indicative of increased social avoidance behavior. Moreover, unlike the young stressed and control groups, only the aged stressed group showed a reduced preference for sucrose, which was correlated with social avoidance behavior. Also, the aged stressed mice exhibited an attenuated defeat-induced increase in water intake. These findings reveal that aging alters behavioral phenotypes after social defeat and that the hedonic behavior of aged mice is more vulnerable to social defeat compared with younger mice.