Under Control? Mouse Models of Heat Exposure: A Systematic Review of Experimental Design and Methodology.

Mouse models are widely used to study heat-related physiological responses as they provide insights relevant to human health. However, species differences (including nocturnal behavior) and standard housing below the thermoneutral zone (TNZ; 26°C-34°C) can confound comparisons. This systematic review evaluates methodologies, including housing temperatures, used in mouse heat-exposure studies published over the past 4 years. Medline, Web of Science, and Embase were searched for peer-reviewed mouse heat-exposure studies published from 2020 to 10 January 2025. Data on housing temperature, heat-exposure protocols, and physiological outcomes were extracted. Screening and extraction were conducted independently and in duplicate in Covidence. One hundred seventy studies were included. Of those, 142 (83%) housed control mice below TNZ; seven (4%) studies maintained TNZ conditions and the remainder did not report control temperature. Heat exposures ranged from 30°C-45°C, most commonly 39°C-41°C. Body temperature was measured in 110 (65%) studies, often targeting ~42°C. When timing was reported, exposures occurred mainly during the light phase (52, 30%). Most studies used males only (116, 68%); 31 (18%) used females only; 9 (5%) included both sexes; and 14 (8%) did not report sex. Common outcomes were digestive (55, 32%), inflammatory (47, 28%), and central nervous system (40, 24%). Recent mouse heat-exposure studies often compare heat-exposed animals with cold-stressed controls and apply daytime exposures that conflict with the nocturnal behavior of mice and human diurnal pattern. Incomplete reporting of housing conditions limits interpretation. Future research should account for differences between mice and humans to improve translational relevance. Trial Registration: PROSPERO: CRD42024611316.