Stress and IL-1beta contribute to the development of depressive-like behavior following peripheral nerve injury.
The physiological link between neuropathic pain and depression remains unknown despite a high comorbidity between these two disorders. A mouse model of spared nerve injury (SNI) was used to test the hypothesis that nerve injury precipitates depression through the induction of inflammation in the brain, and that prior exposure to stress exacerbates the behavioral and neuroinflammatory consequences of nerve injury. As compared with sham surgery, SNI induced mechanical allodynia, and significantly increased depressive-like behavior. Moreover, SNI animals displayed increased interleukin-1beta (IL-1beta) gene expression within the frontal cortex and concurrent increases in the expression of glial fibrillary acidic protein (GFAP) within the periaqueductal grey (PAG). Additionally, exposure to chronic restraint stress for 2 weeks before SNI exacerbated mechanical allodynia and depressive-like behavior, and resulted in an increase in IL-1beta gene expression in the frontal cortex and brain-derived neurotrophic factor (BDNF) gene expression in PAG. Treatment with metyrapone (MET), a corticosteroid synthesis inhibitor, before stress eliminated deleterious effects of chronic stress on SNI. Finally, this study showed that interference with IL-1beta signaling, through administration of IL-1 receptor antagonist (IL-1ra), ameliorated the effects of neuropathic pain on depressive-like behavior. Taken together, these data suggest that peripheral nerve injury leads to increased cytokine expression in the brain, which in turn, contributes to the development of depressive-like behavior. Furthermore, stress can facilitate the development of depressive-like behavior after nerve injury by promoting IL-1beta expression.
Department of Psychology, The Ohio State University, Columbus, OH 43210, USA. norman.106@osu.edu
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Norman
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Karelina
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Zhang
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Walton
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Morris
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Devries
D000704:Analysis of Variance; D000818:Animals; D003345:Corticosterone / Q000097:blood; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003863:Depression / Q000209:etiology*; D004195:Disease Models, Animal; D005106:Exploratory Behavior / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D006930:Hyperalgesia / Q000209:etiology; D053583:Interleukin-1beta / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D017288:Pain Threshold / Q000502:physiology; D010523:Peripheral Nervous System Diseases / Q000150:complications*; D012333:RNA, Messenger / Q000378:metabolism; D013315:Stress, Psychological / Q000503:physiopathology*; D013550:Swimming / Q000523:psychology; D013997:Time Factors
D016207:Cytokines; D053583:Interleukin-1beta; D012333:RNA, Messenger; D003345:Corticosterone