Studying the circadian rhythms governing physiological processes is vital to understanding their impact on health and diseases. However, technological restrictions can impose a practical hurdle in experimental settings employing socially housed animals. We developed a sophisticated telemetry platform, SoHo™, to monitor body temperature and locomotor activity in group-housed small animals. This study aims to validate the SoHo™ telemetry system for monitoring body temperature and locomotor activity in group-housed mice.

CD1 male mice (6 weeks old; N=5) were intraperitoneally instrumented with the SoHo™ telemetry transmitters. The animals were group-housed under a standardized 12-hour dark/light cycle. Synchronized body temperature and locomotor activity were continuously collected for 12 days. Actograms and hourly temperature box plots show the circadian regulation of locomotor activity and body temperature with a positive correlation (r = 0.85). Locomotor activity (in counts per minute; cpm) and body temperature were significantly increased during dark periods compared to light periods (75.7 ± 10.2 cpm vs. 48.1 ± 4.7 cpm; 37.6 ± 0.4 oC vs. 36.4 ± 0.4 oC). The magnitude of locomotor activity and body temperature fluctuations across the circadian cycle were 94.4 ± 37.9 cpm and 3.5 ± 0.7 oC, respectively. The temporal relationship between peaks of locomotor activity and peaks of body temperature yielded a phase angle of 12.9 ± 7.7 minutes.

The data demonstrates that SoHo™ telemetry is a powerful platform for evaluating temperature and activity variations in socially housed mice. Further experiments, such as photoperiod modifications and pharmacological intervention, are needed to address circadian rhythm modulation.