Circadian rhythms on skin function of hairless rats: light and thermic influences.
Circadian rhythms are present in most functions of living beings. We have demonstrated the presence of circadian rhythms in skin variables (transepidermal water loss, TEWL; stratum corneum hydration, SCH; and skin temperature) in hairless rats under different environmental conditions of light and temperature. Circadian rhythms in TEWL and SCH showed mean amplitudes of about 20% and 14% around the mean, respectively, and appeared under light-dark cycles as well as under constant darkness. Environmental temperature was able to override TEWL, but not SCH rhythm, evidencing the dependency of TEWL on the temperature. Mean daily values of TEWL and SCH, and also the amplitude of TEWL rhythm, increased with the age of the animal. Under constant light, situation that induces arrhythmicity in rats, SCH and TEWL were inversely correlated. The results suggest the importance to take into account the functional skin rhythms in research in dermatological sciences.
Departament de Fisiologia, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain; Departament de Farmàcia i Tecnologia Farmacèutica, Facultat de Farmàcia, Universitat de Barcelona, Barcelona, Spain.
Ana
A
Flo
Antoni
A
Díez-Noguera
Ana C
AC
Calpena
Trinitat
T
Cambras
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D008027:Light; D008297:Male; D051381:Rats; D054772:Rats, Hairless; D012881:Skin Temperature / Q000502:physiology*; D013696:Temperature; D014870:Water Loss, Insensible / Q000502:physiology*
TEWL; circadian rhythms; hairless rat; skin; stratum corneum hydration