Related Experiment Videos
Circadian rhythm of phagocytosis in mice
M Hriscu1, G Saulea, N Vidraşcu
1Physiology Dept., University of Medicine and Pharmacy Iuliu Hatieganu, Cluj-Napoca, Romania.
Abstract:
There has been reported, in some diurnal or equivocal species (man, respectively guinea pig), a circadian rhythm of the phagocytic activity of blood neutrophils, with an acrophase occurring at the end of the light span. The present study, carried out on NMRI adult male mice kept on a LD 12:12 regimen, aimed to assess any circadian variation in the blood neutrophils' phagocytosis level. Basal phagocytic activity was tested against E. coli, every three hours of a 24 h cycle. The results show that phagocytosis in mice's blood neutrophils also presents a rhythmic circadian variation, whose acrophase is delayed with about eight hours compared to that in man, occurring in the second half of the dark period (3:00 h). The occurrence of high circadian phagocytic levels appears to be correlated with the activity type of the species and, of this point of view, mice cannot be used as a model for chronotherapeutical approaches in humans, without keeping in mind the differences between the time structure of the two species.
Insights
Mice neutrophils exhibit circadian rhythm in phagocytic activity, peaking in the dark phase. This differs from humans, impacting mice as models for human chronotherapeutics.
Area of Science:
- Immunology
- Chronobiology
Background:
- Circadian rhythms influence physiological processes, including immune cell activity.
- Previous studies indicated diurnal variations in human and guinea pig neutrophil phagocytosis.
Purpose of the Study:
- To investigate circadian variations in blood neutrophil phagocytic activity in mice.
- To compare the timing of peak phagocytic activity between mice and humans.
Main Methods:
- NMRI adult male mice were maintained on a 12:12 light-dark cycle.
- Basal phagocytic activity against E. coli was assessed every three hours over a 24-hour period.
Main Results:
- Mice neutrophils demonstrated a significant circadian variation in phagocytic activity.
- The acrophase (peak activity) in mice occurred approximately eight hours later than in humans, during the latter half of the dark period (around 3:00 AM).
Conclusions:
- Mice exhibit a distinct circadian rhythm of neutrophil phagocytosis, differing in timing from humans.
- Species-specific activity patterns (nocturnal vs. diurnal) correlate with phagocytic rhythm timing.
- Mice may not be a suitable model for human chronotherapeutics without considering these temporal differences.