Murine Depression Model and its Potential Applications for Discovering Foods and Farm Products with Antidepressant-Like Effects

Abstract

Advanced societies face increased health problems related to various stresses. Chronic psychological stress is a major risk factor for psychiatric disorders such as depression. Although therapeutic agents reduce several symptoms of depression, most have side effects in a broad range of the population. Furthermore, some victims of depression do not show significant improvement with any drugs, so alternative approaches are needed. Good dietary habits may potentially reduce depressive symptoms, but there is little scientific evidence thus far. Murine depression models are useful to test nutritional approaches in vivo. Our model mice subjected to a subchronic mild social defeat stress (sCSDS) paradigm show several alterations in physiological parameters and social behavior. These stress-induced symptoms in sCSDS mice can be used as cues to identify antidepressant-like natural resources including foods and farm products. We previously discovered that sCSDS mice show more vulnerability to social stress by changing dietary condition. In addition, we developed a more objective system for analyzing mouse behavior using a 3D depth-sensing camera to understand relationships between diet and behavior. The combination of sCSDS mice with 3D behavioral analysis is a powerful method for screening ingredients in foods and farm products for antidepressant-like effects.

Effects of Diet Quality and Psychosocial Stress on the Metabolic Profiles of Mice

“…Moreover, the locomotor activity of the sCSDS mice was even more inhibited by the presence of social target. This behavioral phenotype under novel environments (conspecies and object) will be a useful indicator in identifying foods and farm products that attenuate social stress-induced deficits …”

“…Because sCSDS mice fed MF diet were less vulnerable to stress than those fed AIN-93G, it may be useful to evaluate antistress supplements using AIN-93G diet-fed sCSDS mice. Further studies of nutritional supplementation using this type of mice are needed …”

“…We previously reported that mice exposed to subchronic and mild social defeat stress (sCSDS) show increased body weight gain, food and water intake, body water content, social avoidance behavior, four liver metabolites, and delays in nest-building behavior when fed a semipurified diet (AIN-93G). − To understand the effect of diet quality on the sCSDS-induced symptoms, we established sCSDS mice using two kinds of dietstandard laboratory diet (nonpurified diet; MF) and AIN-93G (semipurified diet)and evaluated body weight gain, food and water intake, and social avoidance behavior. Although there is no difference in diet composition and calorie content, semipurified and nonpurified diets are produced using chemically pure sources and natural ingredient-based cereal products, respectively .…”

Social defeat models in animal science: What we have learned from rodent models

“…We have found that feed purity influences stress resilience in mice (Goto et al . ,b); therefore, we believe that rodent models provide relevant information relating to feeding management under stressful conditions. Moreover, zoo animals are exposed to various stresses, and abnormal behaviors such as pacing are frequently observed (Koyama et al .…”

“…Therefore, a paradigm that consists of acute social defeat stress and an evaluation of nest quality will be a convenient tool for screening functional foods and reagents that could potentially contribute to the prevention and treatment of depression. Furthermore, in the future, automatic analysis systems for the evaluation of nest quality should be developed for efficient screening (Okayama et al 2015;Goto et al 2016b).…”