G. Tringali et al., Circulating interleukin-1-beta levels after acute and prolonged exposure to low temperatures: Human and rat studies, NEUROIMMUNO, 7(4), 2000, pp. 177-181
In this study we have investigated whether IL-1 acts as a mediator of stres
s responses elicited by exposure to low temperatures. We also sought whethe
r IL-1 is released from the adrenal gland under basal conditions or after e
xposure to low temperatures. Normal and adrenalectomized (ADX) rats were us
ed for acute studies, whereas the effects of a prolonged exposure were inve
stigated in a group of human subjects during a 45-day stay in Antarctica. C
irculating levels of interleukin-1 beta (IL-1 beta) were taken as a marker
of systemic IL-1 production both in humans and rats. In the latter, serum c
orticosterone (Cort) was also estimated. In intact rats, exposure to low te
mperatures (-25 or -35 degrees C) for 30 or 90 min did not modify circulati
ng IL-1 beta levels with respect to controls taken at +20 degrees C. Adrena
lectomy was associated with an increase in cytokine levels only in the grou
p exposed to -35 degrees C for 90 min; such increase is statistically signi
ficant compared to all groups of normal rats, whatever the experimental con
dition, as well as to ADX rats exposed to +20 degrees C and -25 degrees C f
or 30 and 90 min. In normal rats, the increase in circulating Cort levels w
as already maximal after exposure to -25 degrees C for 30 min. In humans, c
irculating IL-1 beta levels after 45 days in Antarctica were significantly
lower than those measured on arrival in the same subjects. Thus, no change
in circulating IL-1 beta was associated with acute low-temperature stress i
n rats, whereas a marked decrease in serum cytokine was observed in humans
after prolonged exposure to a cold environment. Experiments with ADX rats i
ndicated that the contribution of the adrenal glands to total-body IL-1 bet
a production is negligible or absent. Copyright (C) 2000 S. Karger AG. Base
l.