The effect of ambient temperature outweighs acute phase immune activation in regulating surface temperature in Ctenomys talarum
摘要
Thermoregulatory responses are essential for maintaining homeostasis and could be influenced by multiple factors, including ambient temperature (Ta) and immune challenges such as the acute phase response. While changes related to acute phase response in core temperature have been widely studied, the dynamics of surface temperature (Ts) under different Ta conditions remains less explored. Here, we assessed Ts changes in the subterranean rodent Ctenomys talarum during the acute phase response, using infrared thermometry under short-term exposure to three Ta conditions (15 °C, 25 °C, and 32 °C), representing the thermal variation experienced in their natural habitat. Animals received an injection of lipopolysaccharide (LPS, which induces the acute phase response) or saline, and Ts was recorded in several body regions and at different time points. Overall, LPS had no effects on Ts. Instead, Ta strongly influenced Ts, with higher temperatures recorded after exposure to 32 °C. Temporal increases in Ts were observed only under 32 °C. Differences between 15 °C and 32 °C were found for eye and genital temperatures after exposures to this Ta. Positive correlations were found between Ts and core temperature. However, while febrile peaks were observed in rectal temperature, Ts remained relatively unaffected, highlighting limitations in using infrared thermometry to detect thermal changes induced by acute phase response. These findings suggest that while Ts is highly sensitive to Ta and reflects thermoregulatory adjustments, core temperature remains a more reliable indicator of immune activation.