title: Inflammation is increased with anxiety- and depression-like signs in a rat model of spinal cord injury.
abstract: Spinal cord injury (SCI) leads to increased anxiety and depression in as many as 60% of patients. Yet, despite extensive clinical research focused on understanding the variables influencing psychological well-being following SCI, risk factors that decrease it remain unclear. We hypothesized that excitation of the immune system, inherent to SCI, may contribute to the decrease in psychological well-being. To test this hypothesis, we used a battery of established behavioral tests to assess depression and anxiety in spinally contused rats. The behavioral tests, and subsequent statistical analyses, revealed three cohorts of subjects that displayed behavioral characteristics of (1) depression, (2) depression and anxiety, or (3) no signs of decreased psychological well-being. Subsequent molecular analyses demonstrated that the psychological cohorts differed not only in behavioral symptoms, but also in peripheral (serum) and central (hippocampi and spinal cord) levels of pro-inflammatory cytokines. Subjects exhibiting a purely depression-like profile showed higher levels of pro-inflammatory cytokines peripherally, whereas subjects exhibiting a depression- and anxiety-like profile showed higher levels of pro-inflammatory cytokines centrally (hippocampi and spinal cord). These changes in inflammation were not associated with injury severity; suggesting that the association between inflammation and the expression of behaviors characteristic of decreased psychological well-being was not confounded by differential impairments in motor ability. These data support the hypothesis that inflammatory changes are associated with decreased psychological well-being following SCI.
authors: Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX, USA; Department of Psychology, McGill University, Montréal, Québec, Canada. Electronic address: siouimb@gmail.com.
authors: Sioui
authors: S
authors: Maldonado-Bouchard
authors: Department of Psychology, Texas A&M University, College Station, TX, USA.
authors: Kelsey
authors: K
authors: Peters
authors: Anesthesiology, University of California San Diego, San Diego, CA, USA.
authors: Sarah A
authors: SA
authors: Woller
authors: Department of Mathematical Sciences, University of Memphis, TN, USA.
authors: Behrouz
authors: B
authors: Madahian
authors: Department of Mathematics & Computer Science, University of Indianapolis, Indianapolis, USA.
authors: Usef
authors: U
authors: Faghihi
authors: Department of Psychology, Texas A&M University, College Station, TX, USA.
authors: Shivani
authors: S
authors: Patel
authors: Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX, USA.
authors: Shameena
authors: S
authors: Bake
authors: Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, Bryan, TX, USA.
authors: Michelle A
authors: MA
authors: Hook
mesh_terms: D000818:Animals; D001007:Anxiety / Q000209:etiology / Q000276:immunology*; D016207:Cytokines / Q000097:blood / Q000378:metabolism; D003863:Depression / Q000209:etiology / Q000276:immunology*; D004195:Disease Models, Animal; D004660:Encephalitis / Q000209:etiology / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D007249:Inflammation / Q000209:etiology / Q000378:metabolism*; D018836:Inflammation Mediators / Q000097:blood / Q000378:metabolism; D008124:Locomotion; D008297:Male; D009929:Organ Size; D010146:Pain / Q000209:etiology / Q000276:immunology; D017288:Pain Threshold; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function; D013116:Spinal Cord / Q000378:metabolism; D013119:Spinal Cord Injuries / Q000150:complications / Q000276:immunology*; D013950:Thymus Gland / Q000473:pathology; D000511:alpha-Macroglobulins / Q000378:metabolism
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D000511:alpha-Macroglobulins
keywords: Anxiety; Depression; Inflammation; Spinal cord injury