Administration of the endotoxin, lipopolysaccharide (LPS) diminished motor activity and increased plasma corticosterone as well as circulating levels of interleukin-1β (IL-1β), IL-6, tumor necrosis-factor-α (TNF-α) and IL-10. Among cyclooxygenase-2 (COX-2) knockout mice the behavioural, corticosterone and cytokine variations promoted by LPS were moderately (home cage activity, corticosterone, TNF-α) or largely (IL-6) reduced. However, if mice were exposed to a psychosocial stressor (social disruption associated with grouping mice with novel cage-mates after a period of isolation) coupled with LPS treatment, then the effects of the COX-2 deletion were absent, or there was a synergistic or additive elevation apparent (e.g., in the case of TNF-α, IL-6 and corticosterone). Evidently, COX-2 deletion may have either pro- or anti-inflammatory actions, depending upon the psychosocial context in which immune activation occurs.

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Keywords COX-2, Cytokine, Endotoxin, Interleukin, Stress
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Journal Journal of Neuroimmunology
Hayley, S, Mangano, E. (Emily), Strickland, M. (Michael), & Anisman, H. (2008). Lipopolysaccharide and a social stressor influence behaviour, corticosterone and cytokine levels: Divergent actions in cyclooxygenase-2 deficient mice and wild type controls. Journal of Neuroimmunology, 197(1), 29–36. doi:10.1016/j.jneuroim.2008.03.015