Telemetric Evaluation of Body Temperature and Physical Activity as Predictors of Mortality in a Murine Model of Staphylococcal Enterotoxic Shock

Background and Purpose: Hypothermia and death are used as experimental markers in murine models of staphylococcal enterotoxic shock. This study determined whether body temperature and physical activity, monitored telemetrically, could predict impending death and provide an earlier, more humane experimental endpoint. Methods: The study consisted of two iterations (experiments 1 and 2) to determine reproducibility of the model. Each experiment consisted of 24 BALB/c mice surgically implanted with intra-abdominal telemetry transmitters and then injected intraperitoneally with sublethal or lethal doses of staphylococcal enterotoxin B (SEB) and/or lipopolysaccharide (LPS). Core body temperature and physical activity were continuously monitored in all mice for 10 days before, and 5 days after, injections. Additionally, in experiment 2, subcutaneous temperatures were compared with core body temperatures obtained by telemetry. Results: Body temperature and physical activity were reduced in mice after administration of SEB and LPS, or LPS alone, but not SEB only. There was a significant (P < 0.05) correlation between mortality and body temperature (P = 0.0077), but not physical activity (P = 0.97). Conclusion: Body temperature proved to be an early indicator of mortality in this murine model of staphylococcal enterotoxic shock.