Circadian phagocytic activity of neutrophils and its modulation by light
Titel:
Circadian phagocytic activity of neutrophils and its modulation by light
Auteur:
Monica L. Hriscu
Verschenen in:
Journal of applied biomedicine
Paginering:
Jaargang 2 (2004) nr. 4 pagina's 199-211
Jaar:
2004
Inhoud:
The experimental data reviewed herein is aimed at an evaluation of the circadian dynamics ofneutrophil phagocytosis (basal phagocytosis, phagocytic response, and adherence) in mice and ratsand attempts to establish whether the functional pinealectomy accomplished through constant lightexposure affects the level and/or circadian oscillation of the parameters. In both species, basalphagocytic activity appears as a periodic function, peaking in the second half of the night (03:0004:00). Adherence to nylon fibres displays a circadian oscillation with two maxima (10:00 and22:00). Under constant light, the mean phagocytic activity is lowered by 40%, but its circadianamplitude increases, while the acrophase occurs earlier. Both the mean adherence level and itscircadian variation are depressed, the latter to a larger extent. The amplitude and shape of thephagocytic response in non-immunised mice appears to depend on the time of the day whenantigenic stimulation occurs, thus on the phase of the basal rhythm, drawing attention to thenecessity for careful circadian scheduling of immunomodulatory interventions. The results suggestthat rhythmic phagocytosis is part of the immune systems circadian oscillation, controlled byhypothalamic centres and susceptible to modulation under the impact of endogenous andexogenous factors, including melatonin and the light-dark cycle.
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