Rewarming rats at 37˚C rescues hypothermia with significant changes in IL-1β levels in the intestinal tissue and blood

Abstract Background Hypothermia secondary to accidental exposure is becoming increasingly prevalent in the general population; however, the mechanisms and early treatments of hypothermia require additional study. Methods A hypothermia-rewarming SD rat model was established by immersing rats in 15˚C seawater for 5h and then rewarming at 37˚C for 2, 6 and 12 h. The rats were randomly divided into a normal control group (group C), hypothermia group (group H) and rewarming group (group R). The changes in the levels of inflammatory factors and pathophysiology of the intestinal tissues of rats were assessed. The blood was collected in test tubes, and the levels of cytokines in the separated plasma were detected using ELISA. The intestinal tissue was ground and lysed, and protein expression profiles of 67 inflammatory factors were measured using a protein chip. These samples were further subjected to reverse transcription-quantitative (RT-q)PCR analysis and tissue section staining. Results The temperature of the abdomen and the physiological state of the rats was significantly altered during immersion in the hypothermic seawater, and returned to normal after rewarming. The protein chip showed that inflammatory factors, including IL-1β, IL-10 and IL-6, were differentially expressed in the intestine. Using ELISA, it was shown that IL-1β, IL-6 and IL-10 levels were also upregulated in the plasma. Comparing the ratios of IL-1β to IL-6 and IL-1β to IL-10, IL-1β was found to be significantly more upregulated compared with IL-10 and IL-6 in the intestine during hypothermia. The immunohistochemical staining of IL-1β showed that IL-1βexpression first increased then decreased during the rewarming period, and similar results were obtained based on RT-qPCR analysis. Conclusion Rewarming at 37˚C may be a suitable method for early treatment of hypothermia, and IL-1β may serve as a potential biomarker for assessing the severity of hypothermia.