Exhaustive exercise is known to induce muscle damage characterized by inflammation and oxidative stress. Although “regular” and “weekend warrior” exercise regimens have been shown to confer comparable health benefits in human studies, such as reduced risks of all-cause, cardiovascular disease (CVD), and cancer mortality, their differential impacts on muscle damage post-exhaustive exercise remain unclear. This study aimed to compare the effects of long-term, moderate-intensity (LTMI) and short-term, high-intensity (STHI) training modalities, matched for total exercise volume, on gut microbiota, short-chain fatty acids (SCFAs), and exhaustive exercise-induced muscle damage in mice, as well as to evaluate the correlation between these factors. LTMI is considered a regular exercise regimen, while STHI shares some similarities with the “weekend warrior” pattern, such as promoting exercise intensity and condensing training sessions into a short period. Our findings indicate that LTMI training significantly enhanced the abundance of SCFA-producing bacteria, including Akkermansia, Prevotellaceae_NK3B31_group, Odoribacter, Alistipes, and Lactobacillus, thereby increasing SCFA levels and attenuating muscle damage following exhaustive swimming. In contrast, STHI training increased the abundance of opportunistic pathogens such as Staphylococcus and Bilophila, without altering SCFA levels, and was associated with exacerbated muscle damage. Moreover, we observed a significant negative correlation between the abundance of SCFA-producing bacteria and SCFA levels with the expression of inflammatory cytokines in the muscle of mice post-exhaustive exercise. Conversely, the abundance of Staphylococcus and Bilophila showed a notable positive correlation with these cytokines. Additionally, the effects of LTMI and STHI on exhaustive exercise-induced muscle damage were transmissible to untrained mice via fecal microbiota transplantation, suggesting that gut microbiota changes induced by these training modalities may contribute to their contrasting impacts on muscle damage. These results underscore the significance of selecting an appropriate training modality prior to engaging in exhaustive exercise, with implications for athletic training and injury prevention.

Background: The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) has increased worldwide. In recent years, fecal microbiota transplantation (FMT) has become an important promising method for the treatment of MASLD. However, the mechanism remains unclear.Methods: The animal model with C57BL/6 male mice induced by high-fat diet (HFD) for 12 weeks has been introduced. Fecal microbiota and indole-3-carbinol (I3C) was given by oral gavage.Results: Our study demonstrated that a 6-week healthy gut microbiota transplantation tended to ameliorate hepatic steatosis and reverse the decreased liver ILC1 induced by HFD. Interestingly, there was also a negative correlation between liver ILC1 and liver TG, TC level. Furthermore, the protective effect was associated with the elevated levels of serum indole-3-carbinol (I3C). Also, a I3C administration for 6 weeks improved liver steatosis and increased the frequency of liver ILC1 induced by HFD through aryl hydrocarbon receptor (AhR) activation. Moreover, I3C binds to the residues of ALA349, PHE348, LEU309, TYR316, PHE318 on AhR through hydrogen bonds, Π bonds, hydrophobic bonds which was proved by molecular docking.Conclusion: To conclude, our data demonstrated that FMT improved liver steatosis induced by HFD associated with liver ILC1 regulation and indole-3-carbinol level. The study highlighted the potential treatment value of FMT and microbiota-derived I3C in the MASLD treatment and regulation of liver ILC1 function.

Insulin resistance is a common metabolic disease, and its pathogenesis is still unclear. The decrease of glucagon‐like peptide‐1 (GLP‐1) level mediated by the alteration of gut microbiota may be the pathogenesis. The study was to investigate the regulatory effect of dihydromyricetin (DHM) on GLP‐1 level and insulin resistance induced by high‐fat diet (HFD), and to further explore its possible molecular mechanism. Mice were fed an HFD to establish the model of insulin resistance to determine whether DHM had a protective effect. DHM could improve insulin resistance. DHM increased serum GLP‐1 by improving intestinal GLP‐1 secretion and inhibiting GLP‐1 decomposition, associated with the alteration of intestinal intraepithelial lymphocytes (IELs) proportions and decreased expression of CD26 in IELs and TCRαβ⁺ CD8αβ⁺ IELs in HFD‐induced mice. DHM could ameliorate GLP‐1 level and insulin resistance by modulation of gut microbiota and the metabolites, particularly the regulation of chenodeoxycholic acid (CDCA) content, followed by the inhibition of farnesoid X receptor (FXR) expression in intestinal L cells and increased glucagon gene (Gcg) mRNA expression and GLP‐1 secretion. This research demonstrates the role of “gut microbiota‐CDCA” pathway in the improvement of intestinal GLP‐1 levels in HFD‐induced mice by DHM administration, providing a new target for the prevention of insulin resistance.

High-intensity exercise (HIE) induces liver dysfunction and is detrimental to exercise performance. The underlying mechanism and preventive strategy urgently need to be explored. We increased the amount of tryptophan appropriately in the diet and explored the effect of an L-tryptophan-rich diet on the alleviation of HIE-induced liver dysfunction and the underlying mechanism. In this work, by establishing a C57BL/6 mouse model of high-intensity swimming exercise, the results demonstrated an L-tryptophan-rich diet significantly attenuated HIE-induced liver dysfunction, which was associated with increased levels of the tryptophan metabolite indole-3-acetic acid (IAA). Furthermore, IAA indeed exerted a protective effect against HIE-induced liver dysfunction in vivo and LPS-induced hepatocyte dysfunction in vitro. In conclusion, an L-tryptophan-rich diet may be a promising strategy to prevent HIE-induced liver dysfunction and metabolic disturbance via the metabolite indole-3-acetic acid and AhR activation.

Excessive exercise can induce metabolic disturbances that precede overt clinical disease. As the central metabolic organ, the liver plays a pivotal role in systemic metabolic adaptations to exercise, although its dynamic metabolic response remains poorly characterized. Characterizing hepatic metabolic shifts could advance early diagnostic and preventive strategies. Single exhaustive exercise (SEE) is an acute, short‐duration, high exercise load, often used to model a single bout of supra‐physiological exertion, whereas repeated exhaustive exercise (REE) models the cumulative physiological stress induced by consecutive exhaustive exercise sessions. This study systematically delineates temporal metabolic alterations in murine liver following SEE and REE. C57BL/6J mice were subjected to a single bout of exhaustive exercise or daily REE regimens for 7 consecutive days. Liver tissues and serum samples were collected at predetermined intervals (0, 1, 6, 12, 24, 48 h post‐exercise) for comprehensive analysis, including untargeted metabolomics, histopathological evaluation, and quantification of liver injury biomarkers. SEE provoked transient metabolic perturbations that resolved within 24 h, whereas REE induced progressive metabolic remodeling, particularly involving amino acid metabolism. Both exercise modalities caused histologically confirmed hepatic injury, and the biomarkers for liver injury were elevated at an early stage but recovered within 24 h. Multivariate analysis identified “steroid hormone biosynthesis” and “taurine/hypotaurine metabolism” as key modules correlating with injury severity. Time‐series analysis showed that most injury‐related metabolites in the SEE group returned to baseline, whereas those in the REE group remained elevated through 48 h, suggesting sustained metabolic alterations within the observation window, which may reflect delayed recovery and/or adaptive metabolic remodeling in response to repeated exhaustive exercise. Our findings reveal distinct patterns of hepatic metabolic alteration: acute exhaustive exercise triggers self‐limited metabolic adjustments, whereas repeated exhaustive exercise induces more sustained metabolic remodeling. These results underscore the importance of personalized exercise regimens and suggest that modulation of specific metabolic pathways may represent a potential strategy for mitigating exercise‐induced hepatic stress.