In this study, we examined the possible effects of anti-Ly6G-mediated systemic neutrophil depletion and liposome-encapsulated clodronate (LEC)-mediated systemic macrophage depletion on the inflammatory signs (thermal hyperalgesia, mechanical allodynia, oedema and fever) and measured the levels of various inflammation markers (tumour necrosis factor-α (TNF-α), interleukins (IL)-1β, IL-4, IL-10, macrophage inflammatory protein-1 alpha (MIP-1α/CCL3) and myeloperoxidase (MPO) in paw and spinal cord tissues in carrageenan (CG)-induced hindpaw inflammation model in rats.
Treatment with the highest dose of EA-230 resulted in a significant attenuation of the LPS-induced increase in plasma levels of inflammatory mediators interleukin (IL)-6, IL-8, IL-1 receptor antagonist, monocyte chemoattractant protein-1, macrophage inflammatory proteins-1α and -1β, and vascular cell adhesion protein-1 (% reduction of 48, 28, 33, 28, 14, 16 and 19 respectively, p < .01), and reduced fever (peak decrease from 1.8 ± 0.1°C to 1.3 ± 0.2°C, P < .05) and symptom scores (peak decrease from 7.4 ± 1.0 to 4.0 ± 1.2 points, P < .05).
CAPS are associated with GOF mutations in the NLRP3 inflammasome and activation of IL-1ß leading to episodes of fever, cutaneous, musculoskeletal, articular, ocular, and neurological symptoms.
Additional studies showed that CSFV-induced IL-1β secretion was mediated by NLRP3 and that CSFV infection could sufficiently activate the assembly of the NLRP3 inflammasome in monocytes.
The extent to which PGE<sub>2</sub> and other pro-inflammatory cytokines such as TNF-α, IL-6, or IL-1β could be involved in the induction of behavioural fever in fish remains to be clarified.
CAPS are associated with gain-of-function mutations in the NLRP3 inflammasome, a multiprotein complex critical for the activation of IL-1ß, and are characterized by episodes of fever, urticaria-like rash, musculoskeletal, ocular, and neurological symptoms.
Because PGE<sub>2</sub> mediates the pyrogenic effect of IL-1β, these effects might be especially relevant for the role of monocytes in the induction of fever.
Citral given by gavage caused no change in control euthermic rats (treated with saline) but blunted most of the assessed parameters related to the sickness syndrome [fever (hallmark of infection), plasma cytokines (IL-1β, IL-6, and TNF-α) release, and prostaglandin E<sub>2</sub> (PGE<sub>2</sub>) synthesis (both peripherally and hypothalamic)].
Prostaglandin-mediated mechanisms were shown to have important role in the mode of this action of IL-1β, since paracetamol pretreatment partially prevented the development of the above mentioned hyperthermia.
Administration of IL-1ß induced fever, lethargy and anorexia for∼two-to-three days and increased the concentration of IL-1ß in the hippocampus and hypothalamus for at least eight hours.
One case with repeated fever attacks after tonsillectomy showed increased monocyte IL-1β production, similar to the other active case with genetic variants of auto inflammatory disorder-associated genes.
Therefore, P2X7R antagonists emerge as novel therapeutics for the treatment for acute inflammation, pain and fever, with wider anti-inflammatory activity than currently used cyclooxygenase inhibitors.-Barberà-Cremades, M., Baroja-Mazo, A., Gomez, A. I., Machado, F., Di Virgilio, F., Pelegrín, P. P2X7 receptor-stimulation causes fever via PGE2 and IL-1β release.