Background Exertional heat stroke (EHS) is a kind of severe heat illness caused by excessive endogenous heat mainly generated by exercise or labor. Currently, there is no standard experimental animal model for EHS.
Objective To establish a stable and reliable rat model of EHS by using implantable biotelemetry, and elucidate the changes of basic physiological parameters of EHS rats, such as core temperature (Tc), blood pressure (BP), heart rate (HR), in the process of exercise during heat exposure.
Methods A total of 18 adult male Wistar rats, weighing 250-300 g, were intraperitoneally implanted with a wireless radiotelemetry transmitter, which provided remote monitoring of Tc, BP, and HR. After one-week recovery, adaptive running exercise was implemented. After one week of training, rats were brought into an artificial climate chamber, in which the ambient temperature was set to 39.5 ± 0.3℃, relative humidity was 55 ± 5 %. Then, the rats underwent an incremental-speed exercise protocol until fatigue was exhibited. The end point was defined by the appearance of severe disturbance of consciousness, after which the rats were removed from the chamber and recovered at a room temperature. Physiological parameters such as Tc, BP, and HR were continuously monitored during the course, and the survival time was recorded. The EHS rats were dissected immediately after the death and pathological changes were observed.
Results Seven out of eighteen (38.9%) rats underwent the transmitter surgery successfully. By using the biotelemetry model, Tc, BP, and HR of rats were recorded completely during heat stress. With the rapid rise of Tc, BP and HR simultaneously reached the peak and sharply dropped before the end of heat exposure. The histopathological examination verified multiple organ injuries in EHS rats.
Conclusion The application of implantable biotelemetry is helpful in monitoring the physiological parameters, and further investigating the characteristics and mechanism of pathophysiological changes in EHS rats, providing a necessary tool for the follow-up study in EHS.
DownLoad: