Circulating Interleukin-1-Beta Levels after Acute and Prolonged Exposure to Low Temperatures: Human and Rat Studies

• Published in: Neuroimmunomodulation
• Main Authors: Tringali, Giuseppe, Farrace, Stefano, Ragazzoni, Enzo, Dello Russo, Cinzia, Piscitelli, Roberta, Preziosi, Paolo, Navarra, Pierluigi
• Format: Article in Journal/Newspaper
• Language: English
• Published: S. Karger AG 2000
• Subjects: Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1159/000026436; https://www.karger.com/Article/Pdf/26436

In this study we have investigated whether IL-1 acts as a mediator of stress responses elicited by exposure to low temperatures. We also sought whether IL-1 is released from the adrenal gland under basal conditions or after exposure to low temperatures. Normal and adrenalectomized (ADX) rats were used for acute studies, whereas the effects of a prolonged exposure were investigated in a group of human subjects during a 45-day stay in Antarctica. Circulating levels of interleukin-1β (IL-1β) were taken as a marker of systemic IL-1 production both in humans and rats. In the latter, serum corticosterone (Cort) was also estimated. In intact rats, exposure to low temperatures (–25 or –35°C) for 30 or 90 min did not modify circulating IL-1β levels with respect to controls taken at +20°C. Adrenalectomy was associated with an increase in cytokine levels only in the group exposed to –35°C for 90 min; such increase is statistically significant compared to all groups of normal rats, whatever the experimental condition, as well as to ADX rats exposed to +20°C and –25°C for 30 and 90 min. In normal rats, the increase in circulating Cort levels was already maximal after exposure to –25°C for 30 min. In humans, circulating IL-1β levels after 45 days in Antarctica were significantly lower than those measured on arrival in the same subjects. Thus, no change in circulating IL-1β was associated with acute low-temperature stress in rats, whereas a marked decrease in serum cytokine was observed in humans after prolonged exposure to a cold environment. Experiments with ADX rats indicated that the contribution of the adrenal glands to total-body IL-1β production is negligible or absent.