The Central and Peripheral Production of Pro-inflammatory Cytokine, IL-1b after Immune and Stress Stimulation in Rats

ABSTRACT

Interleukin-1beta (IL-1beta), one of the pro-inflammatory cytokines, acts as an endogenous pyrogen and is an important mediator of behavioral and physiological responses to immune stimulation as well as exposure to stressors. The objective of the present study was to examine the pattern of central or peripheral IL-1beta response to lipopolysaccharide (LPS) or exposure to the foot shock stress (FS) in rats. After treatment of LPS (100microgram/kg) or exposure to the FS [ten times (0.8 mA) foot shocks for 5 sec each and 90 sec interval], body temperature and IL-1beta levels in plasma, spleen and brain were measured. Both LPS and FS stimuli elicited increased body temperature but showed different patterns of peripheral IL-1beta levels. LPS produced a widespread increase in IL-1beta levels in the plasma, spleen and brain, whereas FS produced a significant increase in IL-1beta levels only in the brain regions but not in plasma and spleen. The present study suggests that IL-1beta is, centrally or peripherally in different patterns, regulated by immune stimulation or exposure to stressors and IL-1beta plays an important role in mediating responses of sickness-like behaviors induced by immune stimuli or stressors.