A post-injury immune challenge with lipopolysaccharide following adult traumatic brain injury alters neuroinflammation and the gut microbiome acutely, but has little effect on chronic outcomes

IF 4.6 2区 医学 Q1 NEUROSCIENCES
Sarah S.J. Rewell , Ali Shad , Lingjun Chen , Matthew Macowan , Erskine Chu , Natasha Gandasasmita , Pablo M. Casillas-Espinosa , Jian Li , Terence J. O'Brien , Bridgette D. Semple
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引用次数: 0

Abstract

Patients with a traumatic brain injury (TBI) are susceptible to hospital-acquired infections, presenting a significant challenge to an already-compromised immune system. The consequences and mechanisms by which this dual insult worsens outcomes are poorly understood. This study aimed to explore how a systemic immune stimulus (lipopolysaccharide, LPS) influences outcomes following experimental TBI in young adult mice. Male and female C57Bl/6J mice underwent controlled cortical impact or sham surgery, followed by 1 mg/kg i.p. LPS or saline-vehicle at 4 days post-TBI, before behavioral assessment and tissue collection at 6 h, 24 h, 7 days or 6 months. LPS induced acute sickness behaviors including weight loss, transient hypoactivity, and increased anxiety-like behavior. Early systemic immune activation by LPS was confirmed by increased spleen weight and serum cytokines. In brain tissue, gene expression analysis revealed a time course of inflammatory immune activation in TBI or LPS-treated mice (e.g., IL-1β, IL-6, CCL2, TNFα), which was exacerbated in TBI + LPS mice. This group also presented with fecal microbiome dysbiosis at 24 h post-LPS, with reduced bacterial diversity and changes in the relative abundance of key bacterial genera associated with sub-acute neurobehavioral and immune changes. Chronically, TBI induced hyperactivity and cognitive deficits, brain atrophy, and increased seizure susceptibility, similarly in vehicle and LPS-treated groups. Together, findings suggest that an immune challenge with LPS early after TBI, akin to a hospital-acquired infection, alters the acute neuroinflammatory response to injury, but has no lasting effects. Future studies could consider more clinically-relevant models of infection to build upon these findings.
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来源期刊
Experimental Neurology
Experimental Neurology 医学-神经科学
CiteScore
10.10
自引率
3.80%
发文量
258
审稿时长
42 days
期刊介绍: Experimental Neurology, a Journal of Neuroscience Research, publishes original research in neuroscience with a particular emphasis on novel findings in neural development, regeneration, plasticity and transplantation. The journal has focused on research concerning basic mechanisms underlying neurological disorders.
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