Objective: To explore the body temperature threshold of shivering in hyperthermic rats during cooling treatment, and to establish a rat model of different degrees of shivering.
Methods: Male SD rats with body weight of (200 ± 20) g and basic body temperature of 36.8 ℃~38.3 ℃ were heated with 20% dry yeast suspension. Forty rats with successful hyperthermia were selected and randomly divided into four groups, 10 rats in each group. The neck and armpit of the rats with hyperthermia were subjected to exploratory cooling treatment with 10, 20 and 40 mL ice bags for 30 minutes, while the control group was not subjected to cooling. Observe the performance of rat shivering and monitor the anal temperature threshold of rat shivering.
Results: No shivering occurred in any part of the body of the control group and the 10 mL ice bag group in the hyperthermic rats within 30 minutes of cooling treatment; The rats in the 20 mL ice bag group had mild shivering, which was characterized by vertical hair, head and neck trembling, with or without upper limb trembling. The average anal temperature threshold for mild shivering was 37.25 ℃, and the incidence of mild shivering was 100%; The rats in the 40mL ice bag group had severe shivering, which was characterized by vertical hair, severe shivering of head, neck, limbs and trunk, and increased tail muscle tension. The average anal temperature threshold for severe shivering was 37.07 ℃, and the incidence of severe shivering was 90%.
Conclusion: The ideal model of no shivering, mild shivering and severe shivering can be established by ice bag cooling intervention in rats with high fever.