Circadian rhythms modulate the body’s immune system and subsequent response to infection. This study was designed to compare the effects of two circadian disruptors (daylight-restriction and sleep-deprivation) on the immune response in male Swiss mice.
Mice were divided into group 1 (control; n=10), which were neither daylight-restricted nor sleep-deprived and groups 2, 3, 4 and 5 (n=20/group). 10-animals each from groups 2-5 were daylight-restricted for 12, 24, 48 and 72 hours respectively while the remaining animals per group were sleep-deprived for same time interval. Post-exposure, blood was collected into EDTA-coated bottles for haematology (white blood cell (WBC), neutrophils, lymphocyte, monocyte, eosinophils and platelet counts) and plain bottles for serum biochemistry (interferon-γ, superoxide dismutase (SOD), reduced glutathione (GSH), malondialdehyde (MDA).
Compared to control, daylight-restricted and sleep-deprived groups had reduced WBC (12-72 hours), neutrophils (12, 48 and 72 hours) and increased lymphocyte (12, 48 and 72 hours), eosinophil (72 hours) and MDA level (12-72 hours). Daylight-restricted groups exhibited reduced platelets and increased interferon-γ levels at 12-72 hours while sleep-deprived had reduced platelets and increased interferon-γ at 48 and 72 hours only. While SOD decreased in daylight-restricted at 12-72 hours, sleep-deprived had increased values at 12-48 hours, and lowered values at 72 hours. Daylight-restricted had increased GSH level at 12-24 hours and reduced at 48-72 hours while values in sleep-deprived groups were decreased from 12-72 hours respectively.
This study suggests that the onset of anti-immune and oxidative stress effects of daylight-restriction is more sudden than that of sleep-deprivation in male Swiss mice.