Comparison of stress-induced and LPS-induced depressive-like behaviors and the alterations of central proinflammatory cytokines mRNA in rats.
Although proinflammatory cytokine changes in depression have been studied widely, few investigations have searched for specific and common changes in cytokines. In the present study, two animal models of depression were compared: a chronic stress model using forced swim stress and an immune activation model using repeated central lipopolysaccharide (LPS) infusion. The levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 mRNA were examined in the brain regions of the prefrontal cortex, amygdala, and hippocampus using real-time polymerase chain reaction (RT-PCR). It was found that both chronic swim stress and repeated central LPS infusion induced depressive-like behaviors, including decreased body weight, reduced saccharin preference, and increased immobility time or shortened latency of immobility in the tail suspension test. Central TNF-α mRNA expression was elevated in both models and central IL-6 mRNA expression was unchanged in both models. Central IL-1β mRNA expression was increased only in the chronic immune activation model. The findings from this study suggest that TNF-α may be a common risk factor for inflammation in depressive disorders.
Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.|University of Chinese Academy of Sciences, Beijing, China.
Xi-Ting
XT
Guan
Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Wen-Juan
WJ
Lin
Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Ming-Ming
MM
Tang
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000276:immunology; D016207:Cytokines / Q000378:metabolism*; D003863:Depression / Q000139:chemically induced / Q000276:immunology*; D007249:Inflammation / Q000139:chemically induced / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D051381:Rats; D060888:Real-Time Polymerase Chain Reaction; D013312:Stress, Physiological / Q000276:immunology; D013315:Stress, Psychological / Q000276:immunology; D013550:Swimming
D016207:Cytokines; D008070:Lipopolysaccharides; D012333:RNA, Messenger
TNF-α; depression; immune activation; lipopolysaccharide; swim stress