The difference among the depression-like behaviours induced by three widely-used stress models in rats

Abstract

Objective In order to study the difference of depression-like behaviours among three widely-used stress models in rats. Methods The new-born Spragne-Dawley rats were randomly divided into maternal deprivation(MD) group(n=27), chronic mild stress(CMS) group (n=29), dual stress(DS) group (n=31) and control(C) group (n=30) on postnatal day 1.MD rats only received maternal deprivation.CMS rats only received chronic mild stress when 10 weeks old.DS rats received both maternal deprivation and chronic mild stress.Control rats received no experimental handling.Behavior tests including forced swimming test and sucrose consumption which were carried out to evaluate rats' depression-like behaviors in the thirteenth weeks.The extend time of floating and sucrose preference ratio should be recorded in the forced swimming test and sucrose consumption test respectively to reflect the behavior of helplessness and anhedonia of rats. Results In the forced swimming test, the extend floating time of MD group(119.30±65.56)s, CMS group(145.00±80.24)s and DS group(170.03±61.75)s were longer than the control group(81.14±52.40)s(F=11.53, P 0.05). Conclusion The results suggest that MD, CMS and DS may induce some kind of depression-like behaviors in rodents such as anhedonia or the behavior of helplessness and the depression-like behaviors induced by different stresses are similar in male and female individuals. Key words: Stress; Depression-like behavior; Forced swimming test; Sucrose consumption test; Sexual difference