Shenfu Decoction Extends Survival Time of Seawater-Induced Hypothermia in Rats: The Role of Metabolomics and Gut Microbiota

Introduction: Shenfu decoction (SFD), a Traditional Chinese Medicine formula, is used in clinical emergencies. Its effects on seawater-induced hypothermia remain unclear. This study investigates the therapeutic mechanisms of SFD in improving the survival of hy-pothermic rats through metabolomics and gut microbiota analysis. Methods: Hypothermia was induced in rats via seawater immersion. The chemical constitu-ents of SFD were analyzed using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Survival time and rates of low-temperature water-immersed rats were assessed. Rat blood samples were obtained for analysis of hema-tologic parameters, electrolytes, hepatic and renal function, cardiac injury, and inflammatory cytokines. To investigate the potential mechanism underlying the survival-prolonging effect of SFD on seawater-immersed hypothermic rats, untargeted blood metabolomics and gut mi-crobiota profiling were employed for preliminary screening. Results: UPLC-Q-TOF-MS identified almost 50 compounds in SFD, and 1.35 g/kg SFD sig-nificantly extended the survival time of seawater-induced hypothermia rats by 6 hours. After hypothermic seawater immersion, the levels of red blood cells, hemoglobin, hematocrit, as well as serum calcium, phosphorus, blood urea nitrogen, alkaline phosphatase, total protein, cardiac troponin T, and interleukin-6 were significantly increased. However, pretreatment with 1.35 g/kg SFD in rats markedly decreased these parameters. The induction of hypother-mic seawater immersion elevated blood glucose, and the administration of SFD exacerbated this increase in rats. Metabolomic analysis revealed elevated levels of valerenic acid and ben-zoylmesaconine in the SFD group, suggesting the restoration of metabolic homeostasis. This recovery was associated with modulation of the gut microbiota, notably an enhancement of beneficial genera, such as Enterococcus. Discussion: The findings demonstrated that SFD significantly prolonged survival in a rat model of seawater-immersion hypothermia. The protective mechanism involved a dual ac-tion: mitigating hypothermia-induced organ damage and hematological disturbances, coupled with restoring metabolic homeostasis and modulating gut microbiota. SFD has been found to possess specifically enriched beneficial bacterial genera, linked to the activation of brown adipose tissue and non-shivering thermogenesis. This study has provided initial evidence for a gut microbiota-metabolism axis mediating SFD's protective effect. Conclusion: SFD prolonged survival in rats with seawater-induced hypothermia, likely by enhancing thermogenesis and regulating lipid metabolism through gut microbiota changes. The findings highlighted the potential of SFD for hypothermia prevention; however, its exact underlying mechanisms require further validation.