title: Subchronic and mild social defeat stress accelerates food intake and body weight gain with polydipsia-like features in mice.
abstract: Development and characterization of animal models of depression are essential for fully understanding the pathogenesis of depression in humans. We made and analyzed a mouse model exhibiting social deficit and hyperphagia-like behavior using a subchronic and mild social defeat stress (sCSDS) paradigm. The body weight, food and water intake of mice were monitored during a test period, and their behaviors and serum components were analyzed at two stages: immediately after the sCSDS period and 1 month after the sCSDS. The body weight and food intake of defeated mice were significantly higher than control mice at the sCSDS period, and these differences were sustained until 1 month after the sCSDS, whereas the water intake of defeated mice was significantly higher than control mice for the period of sCSDS only. Behavioral analyses revealed that the defeated mice exhibit significant social aversion to unfamiliar mice in a social interaction test and a trend of anxiety-like behavior in an elevated-plus maze test. Possibly due to polydipsia-like symptoms, defeated mice had significantly lower levels of albumin and blood urea nitrogen than control mice immediately after the sCSDS period but not at 1 month after sCSDS. The present study revealed that our sCSDS mice keep much more water in their body than control mice. This study reports the first step toward an understanding of the mechanisms of stress-induced overhydration, over-eating and resultant weight gain.
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan; Ibaraki University Cooperation between Agriculture and Medical Science (IUCAM), Ami, Ibaraki 300-0393, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Goto
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Kubota
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Iio
authors.affiliation: Functional Biomolecules Research Group, The Institute of Livestock and Grassland Science, National Agriculture and Food Research Organization, Ikenodai, Tsukuba 305-0901, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Moriya
authors.affiliation: College of Agriculture, Ibaraki University, Ami, Ibaraki 300-0393, Japan; Ibaraki University Cooperation between Agriculture and Medical Science (IUCAM), Ami, Ibaraki 300-0393, Japan; United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, Fuchu-city, Tokyo 183-8509, Japan. Electronic address: atoyoda@mx.ibaraki.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Toyoda
mesh_terms: D000818:Animals; D001007:Anxiety / Q000523:psychology*; D001835:Body Weight; D004435:Eating / Q000523:psychology*; D006963:Hyperphagia / Q000523:psychology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D059606:Polydipsia / Q000523:psychology*; D012919:Social Behavior; D013315:Stress, Psychological / Q000150:complications* / Q000523:psychology; D015430:Weight Gain
keywords: Behavior; Hyperphagia; Mouse; Polydipsia; Serum; Social defeat stress