Validation of the SoHo™ Telemetry System for Continuous Body Temperature Monitoring in Socially Housed Mice

Monitoring body temperature is critical in pharmacological studies to evaluate the physiological effects of test compounds, including their potential to induce hypothermia or fever. Short-term body temperature changes, such as reductions and subsequent recoveries, provide valuable insights into compound safety and pharmacodynamics. This study aimed to validate a novel telemetry system, SoHo™, for continuous temperature monitoring in group-housed mice (3-5 mice per cage). Healthy adult (C57BL/6NTac (75%) / 129S6SvEvTac (25%)) mice were subcutaneously implanted with SoHo transmitters (model SoHo-X00N), and body temperature was continuously monitored using the SoHo™ telemetry system and as specified timepoints with a rectal themometer. The studies showed that the probes do not affect the mouse body weights (day 1: 32.7 ± 0.74 g, day7: 33.3± 0.62). The data dropouts were minimal (0.35 %). Temperatures measured after the implantation with the probes showed similar results to rectal measurements. First, we evaluated the effects of the surgical placement of the device on body temperature measurements. No significant differences were observed in temperature recordings between dorsal and flank implantations on day one (dorsal 34.8 ± 0.28 °C; flank 35.1 ± 0.14 °C) or day 7 (dorsal 35.6 ± 0.34 °C; flank 36.55 ± 0.30 °C) post-surgery. The delta temperatures from flank between rectal and probe were smaller than dorsal during baseline (7 days after implantation). Therefore, flank implantation was selected for subsequent studies. Next, IgE mediated anaphylaxis was induced with administration of MAR-1 and body temperature responses were asseses. Body temperature reductions were dose- and time-dependent: at 30 minutes post-challenge, reductions were 1.2 ± 0.22 °C for the vehicle group (N = 10), 4.3 ± 1.2 °C at 0.25 mg/kg (N = 5), 6 ± 0.27 °C at 0.50 mg/kg (N = 11), and 5.1 ± 0.3 °C at 0.75 mg/kg (N = 10). Temperature nadirs were between 30 and 60 minutes for all doses and normalized within 240 minutes. Lastly, we studied recovery from anesthesia-induced hypothermia, revealing time-dependent recovery. After two minutes of anesthesia (N = 32 mice), the temperature decrease was 2.5 ± 0.2 °C and 0.4 ± 0.1 °C at 20- and 60-minutes post-anesthesia, respectively. The data shown suggest that probes are more sensitive to small changes than rectal thermometer. These findings confirm the SoHo telemetry system as a reliable tool for continuous temperature monitoring in socially housed mice. This validation supports its application in preclinical compound testing and safety evaluations. This study was supported by DSI and Regeneron Pharmaceuticals This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.