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Croatian Medical Journal, Vol. 52 No. 5, 2011.

Original scientific paper

The impact of sleep deprivation and nighttime light exposure on clock gene expression in humans

Pavel Kavčič ; Institute of Clinical Neurophysiology, Division of Neurology, University Medical Centre, Ljubljana, Slovenia
Bojan Rojc ; Institute of Clinical Neurophysiology, Division of Neurology, University Medical Centre, Ljubljana, Slovenia
Leja Dolenc-Grošelj ; Institute of Clinical Neurophysiology, Division of Neurology, University Medical Centre, Ljubljana, Slovenia
Bruno Claustrat ; Hormone Laboratory, Nuclear Medicine Centre, Bron, France
Kristina Fujs ; Institute of Microbiology and Immunology, Medical Faculty of Ljubljana, Ljubljana, Slovenia

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Abstract

Aim To examine the effect of acute sleep deprivation under
light conditions on the expression of two key clock genes,
hPer2 and hBmal1, in peripheral blood mononuclear cells
(PBMC) and on plasma melatonin and cortisol levels.
Methods Blood samples were drawn from 6 healthy individuals
at 4-hour intervals for three consecutive nights,
including a night of total sleep deprivation (second night).
The study was conducted in April-June 2006 at the University
Medical Centre Ljubljana.
Results We found a significant diurnal variation in hPer2
and hBmal1 expression levels under baseline (P < 0.001,
F = 19.7, df = 30 for hPer2 and P < 0.001, F = 17.6, df = 30 for
hBmal1) and sleep-deprived conditions (P < 0.001, F = 9.2,
df = 30 for hPer2 and P < 0.001, F = 13.2, df = 30 for hBmal1).
Statistical analysis with the single cosinor method revealed
circadian variation of hPer2 under baseline and of hBmal1
under baseline and sleep-deprived conditions. The peak
expression of hPer2 was at 13:55 ± 1:15 hours under baseline
conditions and of hBmal1 at 16:08 ± 1:18 hours under
baseline and at 17:13 ± 1:35 hours under sleep-deprived
conditions. Individual cosinor analysis of hPer2 revealed a
loss of circadian rhythm in 3 participants and a phase shift
in 2 participants under sleep-deprived conditions. The
plasma melatonin and cortisol rhythms confirmed a conventional
alignment of the central circadian pacemaker to
the habitual sleep/wake schedule.
Conclusion Our results suggest that 40-hour acute sleep
deprivation under light conditions may affect the expression
of hPer2 in PBMCs

Keywords

Sleep deprivation; light exposure; clock genes; hPer2, hBmal1; peripheral blood mononuclear cells

Hrčak ID:

74213

URI

https://hrcak.srce.hr/74213

Publication date:

15.10.2011.

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