Exertional heat stroke (EHS) is a life-threatening condition induced by high-temperature environments, which poses significant health risks. The Qingshu Yiqi Decoction (QSYQD) is a traditional Chinese medicine (TCM) formula that is known to clear summer heat, replenish Qi, and protect intestinal function. However, experimental evidence and mechanistic insights into its role in EHS prevention are limited. The aim of this study is to evaluate the protective effects of QSYQD against EHS-induced hyperthermia and multi-organ injury and investigate the underlying molecular mechanisms. An EHS rat model was established using treadmill exercise in a high-temperature environment. The rats were pretreated with low, medium, or high doses of the QSYQD. The intestinal barrier function was assessed using biomarkers, an ultrastructural analysis, and key protein expressions. Network pharmacology was used to identify potential targets, and molecular mechanisms were validated using western blot. The gut microbiota composition was analyzed using 16S rRNA sequencing. The QSYQD significantly alleviated hyperthermia and multi-organ injury in the EHS rats, and the medium dose had the most pronounced effects. It preserved intestinal barrier integrity by maintaining the tight junction protein levels and reducing biomarkers of epithelial damage. Network pharmacology and experimental validation revealed that the QSYQD inhibited the NF-κB and MLC signaling pathways, key regulators of intestinal barrier function. Additionally, the QSYQD altered the gut microbiota composition and notably increased the abundance of Lactobacillus, that has known heat stress protective effects. QSYQD protects against EHS-induced damage by preserving intestinal barrier integrity, modulating gut microbiota, and inhibiting the NF-κB and MLC signaling pathways. Future studies will focus on identifying active compounds within QSYQD that enhance heat tolerance and provide EHS protection.

Conventional inorganic semiconductors are not suitable for acting as nanozymes or sonosensitizers for in vivo therapeutic nanomedicine owing to the lack of excellent biocompatibility. Biocompatible carbon dots (CDs) exhibit a variety of biological activities due to their adjustable size and surface chemical modification; however, the simultaneous sonodynamic activity and multiple enzyme-mimicking catalytic activity of a single CD have not been reported. Herein, we report the development of bimetallic doped CDs as a high-efficiency nanozyme and sonosensitizer for enhanced sonodynamic therapy (SDT) and nanocatalytic therapy (NCT). By selecting metal–organic complexes like EDTA–FeNa as the carbon source, we ensure that the coordination environments of metal atoms are preserved throughout the low-temperature calcination process. Compared with the single metal doped CDs including Fe–CDs or Ni–CDs, the obtained Fe and Ni co-doped CDs (Fe–Ni–CDs) not only exhibit enhanced sonodynamic activity owing to the decreased bandgap, but also possess augmented dual enzyme-mimicking catalytic activities due to the synergistic effect of bimetallic ions. The Fe–Ni–CD-mediated cascade amplification of ROS generation could lead to the production of ¹O₂ and O₂˙⁻ through SDT, the generation of ˙OH through POD-mimicking catalytic activity, and the provision of more O₂ for SDT through CAT-mimicking catalytic activity. Through the integrated multifunctionality of Fe–Ni–CDs, we successfully enhanced the effectiveness of antitumor treatment with a single drug injection and a single US irradiation for enhanced SDT and NCT. This work provides a distinct paradigm of endowing CDs with sonodynamic and multiple enzyme-mimicking catalytic activities for enhanced SDT and NCT through bimetallic ion doping.

Heat stroke (HS) is a severe condition associated with prolonged exposure to high temperatures, leading to systemic inflammation and multi-organ damage. Disruption of the intestinal barrier plays a crucial role in HS progression by allowing endotoxins to enter circulation and trigger widespread inflammation. Lactoferrin (LF), known for its immune-modulating and barrier-protective properties, shows promise in mitigating HS-related damage. This study investigated the protective effects of LF on the intestinal barrier under HS conditions using in vitro and in vivo models. In Caco-2 cell monolayers exposed to heat stress, LF improved barrier integrity by increasing transepithelial electrical resistance (TEER) and maintaining tight junctions. In mice, LF supplementation enhanced heat tolerance, delayed HS onset, and reduced multi-organ damage, whereas LF knockout (KO) mice exhibited exacerbated damage. Further analysis revealed that heat stress induced ferroptosis by suppressing GPX4 and SLC7A11, contributing to intestinal injury. LF alleviated ferroptosis by upregulating these proteins and reducing Fe²⁺ accumulation, reactive oxygen species (ROS) generation, and lipid peroxidation. Additionally, LF inhibited heat stress-induced activation of the MAPK pathway by suppressing the phosphorylation of p38, ERK, and JNK, suggesting that MAPK signaling mediates its protective effects. These findings suggest that LF supplementation may enhance heat tolerance and prevent HS-induced intestinal barrier damage through ferroptosis inhibition and MAPK pathway regulation.

As global warming intensifies, heat waves occur more frequently around the world. Heat stress from hot and humid environments poses a significant threat to human health. It can cause a significant increase in core body temperature (CBT), and even lead to life-threatening heat stroke. Extremely high CBT is considered the most important clinical symptom and prognostic indicator of heat stroke. To study it, we implanted temperature-monitoring capsules into the abdominal cavities of rats to measure their CBT values. The rats were then exposed to different hot and humid environments to monitor the resultant changes in their CBTs. The results showed that heat stress could induce a three-phase thermoregulatory response in rats under different conditions. A temperature plateau was observed as part of the three-phase thermoregulatory response, at a similar CBT across different conditions. The duration of this plateau can reflect the thermotolerance of rats in hot and humid environments. The third stage of the three-phase thermoregulatory response reflects the pathogenesis of heat stroke, which may present the key stage of heat injury. Moreover, a certain range of humidity did not affect the thermoregulatory responses of rats, but exerted a significant impact once a certain threshold was reached. In this study, the CBTs of the rats in different environments were monitored to characterize their thermoregulatory responses under heat stress. In particular, the discovery of the plateau phase and humidity threshold may help to better understand the effects of high temperature and humidity conditions on living organisms.

Heat stroke (HS) is the most severe heat-related emergency, and its pathophysiology remains largely unknown, especially for exertional HS (EHS), which affects younger populations, athletes, and manual workers. Herein, we performed single-cell-transcriptomics, T cell receptor sequencing, and flow cytometry of PBMCs from 9 healthy control participants, 9 patients with heat exhaustion, and 9 patients with EHS to explore complex immunological responses associated with HS pathobiology. We showcased that granzyme-positive T cells and CD56 ^dim NK cells with high cytotoxicity features and IL-1B ⁺ NLRP3 ⁺ monocytes with high inflammation and pyroptosis scores were enriched in HS, while the CD161 ⁺ T cells with innate immune-like, low cytotoxicity, and clonal expansion features were reduced in HS. Importantly, elevated granzyme-positive T and NK cells might interact with monocytes to induce pyroptosis of hepatic and renal cells and target organ injuries, and blocking the NLRP3 inflammasome pathway prior to the induction could alleviate organ injury in HS. This study offers deeper insights into the pathogenesis of HS, supporting the development of optimal treatment strategies.

Heat stroke (HS) is a life-threatening condition exacerbated by rising global temperatures, with children identified as a particularly vulnerable population. Despite this, basic research on age-related differences in thermotolerance remains limited. In this study, we established a high-temperature and high-humidity exposure model with real-time core body temperature (CBT) monitoring to investigate thermotolerance in young versus adult rats. The results showed that young rats exhibited prolonged CBT plateau phases and delayed HS onset, indicating enhanced thermotolerance compared to adult rats. This was accompanied by significantly milder multi-organ injury and reduced intestinal barrier damage. Young rats displayed lower serum levels of D-lactate and intestinal fatty acid-binding protein, better-preserved intestinal epithelial ultrastructure, and higher expression of tight junction proteins such as ZO-1, Occludin, and E-cadherin. Moreover, young rats showed elevated expression of heat shock proteins (HSP40 and HSP70) in intestinal tissues, which likely contributed to improved barrier integrity and cellular protection. These findings suggest that enhanced intestinal barrier stability and robust HSP responses underlie the superior thermotolerance observed in young rats. However, despite their physiological advantages, infants and young children often suffer poor HS outcomes due to behavioral limitations and caregiver negligence, especially in enclosed environments such as parked vehicles. This highlights the critical need for enhanced caregiver awareness, improved pediatric emergency response training, and preventive strategies to mitigate pediatric HS risk.