Objective: To characterize longitudinal trajectories of testicular development in boys and breast development in girls, so as to provide reference data for understanding patterns of pubertal sexual maturation. Methods: Based on the Shanghai Pudong New Area Cohort Study on Growth, Development and Health in Children and Adolescents, a baseline survey was conducted in 2020 using a mult stage cluster random sampling method. A total of 2 184 children who completed all follow ups during the primary school period from 13 elementary schools in Pudong New Area,Shanghai,with annual follow ups during 2021-2025. Testicular volume and Tanner stage of breast development were assessed by professional physicians using standardized visual inspection and palpation. The age distribution of testicular volume and breast development was fitted by using cumulative link mixed models and Turnbull s nonparametric maximum likelihood estimation method. Results: Median ages for testicular volumes of 2, 3, 4 and 5 mL in boys were 7.07, 9.24, 10.29, and 11.57 years old, respectively. Median ages for Tanner breast stages Ⅱ, Ⅲ, Ⅳ, and Ⅴ in girls were 8.55 , 10.17, 11.18, and 13.78 years old, respectively. Based on overweight and obesity, stratified analysis showed that earlier pubertal onset among overweight/obesity children, and the key milestones for pubertal initiation were testicular volume reaching 4 mL in boys and breast Tanner II in girls for 10.29, 10.83; 8.18, 9.00 years. Conclusion Overweight and obesity are associated with earlier pubertal initiation,but there are certain gender and developmental stage specific patterns.

ObjectiveTo investigate the mechanism by which Notoginsenoside R1 （NGR1） ameliorates hypoxia/reoxygenation （H/R）-induced injury in AC16 human cardiomyocyte cell lines through the regulation of mitophagy. MethodsCommon genes linked to hypoxia/reoxygenation injury and mitophagy were identified by intersecting data from GeneCards and MitoCarta databases. AC16 cell viability was assessed via CCK-8 assay under varying NGR1 concentrations （0， 6.25， 12.5， 25， 50， 100， 200， 300， 400， 500 μmol/L）. AC16 cells were divided into the following groups： control group （Control）， model group （H/R）， and treatment groups （H/R + NGR1 at 100， 200 and 300 μmol/L）. Mitochondrial membrane potential （ΔΨm） was measured using 5，5'，6，6'-tetrachloro-1，1'，3，3'-tetraethylbenzimidazolylcarbocyanine iodide （JC-1） staining. Transcriptional levels of mitophagy-related genes （Parkin， Pink1， P62） were quantified by reverse transcription-quantitative PCR （RT-qPCR）. Protein expression of mitophagy-related markers （Parkin， Pink1， P62， and LC3BⅡ） was evaluated via Western blot analysis. Mitochondrial ultrastructure was visualized by transmission electron microscopy （TEM）. ResultsCompared to the control group， cell viability in the H/R group significantly decreased （P<0.01）. Treatment with NGR1 at concentrations above 100 μmol/L significantly enhanced the cell viability of AC16 cells compared to the H/R group （P<0.01）. H/R induced a significant decrease in mitochondrial membrane potential （P<0.01）， which was restored by NGR1 treatment （P<0.01）. The mRNA levels of Parkin， Pink1， and P62 in the H/R group were upregulated compared to the control group （P<0.05）， while NGR1 intervention downregulated their expression （P<0.05）. Protein expression levels of Parkin， Pink1， and LC3BⅡ in the H/R group significantly increased， while P62 expression decreased compared to the control group （P<0.01）. In contrast， different doses of NGR1 treatment significantly reduced the expression of Parkin， Pink1， and LC3BⅡ while increasing P62 expression （P<0.05）. TEM revealed that the mitochondrial structure in the H/R group was severely disrupted， with fragmented and disorganized cristae， which was alleviated by NGR1. ConclusionNGR1 ameliorates H/R-induced AC16 cell injury， and its mechanism may be associated with modulating the Pink1/Parkin pathway to suppress excessive mitophagy.

Objective:To analyze the clinical characteristics of children with head and neck rhabdomyosarcoma (RMS) and to summarize the mid-long term efficacy of Beijing Children′s Hospital Rhabdomyosarcoma 2006 (BCH-RMS-2006) regimen and China Children′s Cancer Group Rhabdomyosarcoma 2016 (CCCG-RMS-2016) regimen.Methods:A retrospective cohort study. Clinical data of 137 children with newly diagnosed head and neck RMS at Beijing Children′s Hospital, Capital Medical University from March 2013 to December 2021 were collected. Clinical characteristic of patients at disease onset and the therapeutic effects of patients treated with the BCH-RMS-2006 and CCCG-RMS-2016 regimens were compared. The treatments and outcomes of patients with recurrence were also summarized. Survival analysis was performed by Kaplan-Meier method, and Log-Rank test was used for comparison of survival rates between groups.Results:Among 137 patients, there were 80 males (58.4%) and 57 females (41.6%), the age of disease onset was 59 (34, 97) months. The primary site in the orbital, non-orbital non-parameningeal, and parameningeal area were 10 (7.3%), 47 (34.3%), and 80 (58.4%), respectively. Of all patients, 32 cases (23.4%) were treated with the BCH-RMS-2006 regimen and 105 (76.6%) cases were treated with the CCCG-RMS-2016 regimen. The follow-up time for the whole patients was 46 (20, 72) months, and the 5-year progression free survival (PFS) and overall survival (OS) rates for the whole children were (60.4±4.4)% and (69.3±4.0)%, respectively. The 5-year OS rate was higher in the CCCG-RMS-2016 group than in BCH-RMS-2006 group ((73.0±4.5)% vs. (56.6±4.4)%, χ2=4.57, P=0.029). For the parameningeal group, the 5-year OS rate was higher in the CCCG-RMS-2016 group (61 cases) than in BCH-RMS-2006 group (19 cases) ((57.3±7.6)% vs. (32.7±11.8)%, χ2=4.64, P=0.031). For the group with meningeal invasion risk factors, the 5-year OS rate was higher in the CCCG-RMS-2016 group (54 cases) than in BCH-RMS-2006 group (15 cases) ((57.7±7.7)% vs. (30.0±12.3)%, χ2=4.76, P=0.029). Among the 10 cases of orbital RMS, there was no recurrence. In the non-orbital non-parameningeal RMS group (47 cases), there were 13 (27.6%) recurrences, after re-treatment, 7 cases survived. In the parameningeal RMS group (80 cases), there were 40 (50.0%) recurrences, with only 7 cases surviving after re-treatment. Conclusions:The overall prognosis for patients with orbital and non-orbital non-parameningeal RMS is good. However, children with parameningeal RMS have a high recurrence rate, and the effectiveness of re-treatment after recurrence is poor. Compared with the BCH-RMS-2006 regimen, the CCCG-RMS-2016 regimen can improve the treatment efficacy of RMS in the meningeal region.

Malignant tumors are one of the major diseases that endanger human life and health. Chinese medicine has unique advantages in clinical anti-tumor treatment. However， how to translate the anti-tumor effects of Chinese medicine into clinical practice is the core issue that must be addressed in the process of treating malignant tumors with traditional Chinese medicine （TCM）. Unlike modern chemical drugs， the compatibility application of Chinese medicine is the key factor that determines whether Chinese medicine can achieve optimal anti-tumor efficacy and realize the goal of "enhancing efficacy and reducing toxicity". The formulation structure based on this compatibility is the basic form for the safe， efficient， and rational clinical use of anti-tumor Chinese medicine， and it mainly includes three categories： herb pairs， tri-herbal combinations， and compound compatibility. Although herb pairs have the characteristics of a simple structure and strong targeting （enhancing efficacy and reducing toxicity）， they often have a single effect and cannot fully address the complex pathogenesis of tumors. As a result， herb pairs are rarely used alone in practice. Compared to herb pairs， tri-herbal combinations broaden the application scope of herbs in clinical treatment， but their therapeutic range remains limited. The traditional "sovereign， minister， assistant， and guide" compound prescription， which includes herb pairs and tri-herbal combinations， improves the efficacy of herbs in treating serious diseases， hypochondriasis， chronic diseases， and miscellaneous disorders. However， due to the limitations of its historical background， it has not been integrated with modern clinical practice and modern pharmacological research， which restricts the development of compound compatibility theory. With the emergence of modern medical technology， it has been combined with traditional compatibility theory of Chinese medicine to create an innovative modern compatibility theory. This includes the "aid medicine" theory derived from modern Chinese medicine pharmacology， which compensates for the inability of the "sovereign， minister， assistant， and guide" theory to accurately apply medicine. Additionally， the "state-targeted treatment based on syndrome differentiation" theory， developed from pharmacology and modern medicine， addresses the deficiency in disease cognition in the "sovereign， minister， assistant， and guide" theory. Under the guidance of these compatibility forms and theories， clinical anti-tumor Chinese medicine can exert its maximum anti-tumor efficacy， which is of great significance for the application of Chinese medicine in clinical tumor treatment.

Objective To observe the clinical efficacy of Dan Qi Yishen Prescription in treating diabetic nephropathy(DN)and explore its renal protective mechanism.Methods A total of 150 patients with DN of qi-yin deficiency complicated with blood stasis syndrome who admitted to Sanya Hospital of Traditional Chinese Medicine Affiliated to Guangzhou University of Chinese Medicine from October 2021 to April 2023 were divided into a control group and an observation group according to the random number table method,with 75 patients in each group.Both groups were given conventional therapies such as dietary treatment,blood glucose control,blood pressure control,lipid-lowering treatment and treatment of complications.Additionally,the control group was given intravenous injection of reduced glutathione,while the observation group was given oral use of the decoction of Dan Qi Yishen Prescription and ionic introduction of Dan Qi Yishen Prescription in renal region.Thirty days constituted one course of treatment,and both groups were treated for three courses.Before and after treatment,the scores of traditional Chinese medicine(TCM)syndrome,and the levels of renal function indicators,renal hemodynamic indicators,coagulation and fibrinolysis indicators,and vascular endothelial function indicators in the two groups were observed.Results(1)After treatment,the scores of TCM symptoms such as fatigue and weakness,palpitations and shortness of breath,dizziness and tinnitus,spontaneous sweating and night sweating,restlessness and insomnia,and thirst with preference for drinks in the two groups were decreased compared with those before treatment(P<0.01),and the decrease in the observation group was significantly superior to that in the control group(P<0.01).(2)After treatment,the levels of renal function indicators such as blood urea nitrogen(BUN),serum creatinine(SCr),collagen Ⅳ(CⅣ),and plasma laminin(LN)of patients in the two groups were improved compared with those before treatment(P<0.01),and the improvement in the observation group was significantly superior to that in the control group(P<0.01).(3)After treatment,the levels of renal hemodynamic indicators such as systolic maximum blood flow velocity(Vsmax)and diastolic minimum blood flow velocity(Vdmin)of the main renal artery(MRA)and interlobar artery(IRA)in the two groups were increased compared with those before treatment(P<0.05 or P<0.01),while the resistance index(RI)and pulsatility index(PI)of MRA and RI of IRA in the two group as well as PI of IRA in the observation group were decreased compared with those before treatment(P<0.05 or P<0.01).The increase of Vsmax and Vdmin of MRA and IRA as well as the decrease of RI and PI of MRA and IRA in the observation group was significantly superior to that in the control group(P<0.05 or P<0.01).(4)After treatment,the levels of coagulation and fibrinolysis indicators such as prothrombin time(PT),activated partial thromboplastin time(APTT),D-dimer(D-D),and fibrinogen(FIB)in the two groups were improved compared with those before treatment(P<0.01),and the improvement in the observation group was significantly superior to that in the control group(P<0.01).(5)The analysis of vascular endothelial function indicators showed that after treatment,the serum vasohibin 1(VASH-1)level in the two groups was increased compared with that before treatment(P<0.01),and the serum vascular endothelial growth factor(VEGF)and endothelin 1(ET-1)levels were decreased compared with those before treatment(P<0.01),and the increase of serum VASH-1 level as well as the decrease of serum VEGF and ET-1 levels in the observation group was significantly superior to that in the control group(P<0.01).Conclusion Dan Qi Yishen Prescription exerts good clinical efficacy in treating patients with DN of qi-yin deficiency complicated with blood stasis syndrome,and it has protective effect on renal function probably by improving the coagulation and fibrinolysis system and vascular endothelial function of the patients.

OBJECTIVE: To observe the effect of electroacupuncture (EA) pretreatment of "biaoben acupoint combination" on cardiomyocyte mitochondrial fission in the rats with myocardial ischemia-reperfusion injury (MIRI) and explore its mechanism. METHODS: Fifty male SD rats were randomly divided into a sham-operation group, a model group, an EA pretreatment group, an EA pretreatment + Compound C group and an EA pretreatment+ML385 group, 10 rats in each group. In the EA pretreatment, the EA pretreatment + Compound C group and the EA pretreatment+ML385 group, EA was delivered at bilateral "Neiguan" (PC6), "Zusanli" (ST36) and "Guanyuan" (CV4) for 20 min, with continuous wave and 2 Hz of frequency, 1 mA of current, once daily for consecutive 7 days. On day 8, in the EA pretreatment + Compound C group and the EA pretreatment+ML385 group, 30 min before model preparation, the intraperitoneal injection with Compound C (0.3 mg/kg) and ML385 (30 mg/kg) was administered respectively. Except in the sham-operation group, the ligation of the left anterior descending coronary artery was performed to prepare MIRI rat model in the rest groups. In the sham-operation group, the thread was not ligated. After modeling, the content of reactive oxygen species (ROS) in the ischemic area was measured by flow cytometry, superoxide dismutase (SOD) was detected using xanthine oxidase method, and malondialdelyde (MDA) was detected using thiobarbituric acid (TBA) chromatometry. The morphology of myocardial tissue in the ischemic area was observed with HE staining, and the mitochondria ultrastructure of cardiomyocytes observed under transmission electron microscopy. Using immunofluorescence analysis, the positive expression of mitochondrial fission factor (MFF), mitochondrial fission 1 protein antibody (Fis1) and dynamin-related protein 1 (Drp1) was detected; and with immunohistochemical method used, the protein expression of adenosine monophosphate-activated protein kinase (AMPK), nuclear factor E2-associated factor2 (Nrf2) and Drp1 in the ischemic area was detected. RESULTS: Compared with the sham-operation group, the content of ROS and MDA in the myocardial tissue of the ischemic area, and the positive expression of MFF, Fis1 and Drp1 increased in the model group (P<0.01); the content of SOD and the protein expression of AMRK and Nrf2 decreased (P<0.01), and the protein expression of Drp1 elevated (P<0.01). Compared with the model group, the content of ROS and MDA in the myocardial tissue of the ischemic area, and the positive expression of MFF, Fis1 and Drp1 were dropped in the EA pretreatment group (P<0.01); the content of SOD and the protein expression of AMRK and Nrf2 rose (P<0.01), and the protein expression of Drp1 declined (P<0.01); and in the EA pretreatment+Compound C group and the EA pretreatment+ML385 group, the positive expression of MFF, Fis1 and Drp1, and the protein expression of Drp1 were all reduced (P<0.01). When compared with the EA pretreatment + Compound C group and the EA pretreatment+ML385 group, the content of ROS and MDA in the myocardial tissue of the ischemic area, and the positive expression of MFF, Fis1 and Drp1 were dropped in the EA pretreatment group (P<0.01); the content of SOD and the protein expression of AMRK and Nrf2 rose (P<0.01, P<0.05), and the protein expression of Drp1 decreased (P<0.05). In comparison with the model group, the EA pretreatment+Compound C group and the EA pretreatment+ML385 group, the cardiac muscle fiber rupture, cell swelling and mitochondrial disorders were obviously alleviated in the EA pretreatment group. The morphological changes were similar among the model group, the EA pretreatment+Compound C group and the EA pretreatment+ML385 group. CONCLUSION Electroacupuncture pretreatment of "biaoben acupoint combination" attenuates myocardial injury in MIRI rats, probably through promoting the phosphorylation of AMPK and Nrf2, inhibiting the excessive mitochondrial fission induced by Drp1, and reducing mitochondrial dysfunction caused by mitochondrial fragmentation and vacuolation.
Animals ; Electroacupuncture ; Male ; Rats, Sprague-Dawley ; Myocardial Reperfusion Injury/physiopathology* ; Myocytes, Cardiac/cytology* ; Rats ; Acupuncture Points ; Mitochondrial Dynamics ; Humans ; Reactive Oxygen Species/metabolism* ; NF-E2-Related Factor 2/genetics* ; Superoxide Dismutase/metabolism*

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021,and provide evidence for rational use of antimicrobial agents.Methods Data of H.influenzae and M.catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis,and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET.The results were interpreted according to the CLSI breakpoints in 2022.Beta-lactamases was detected by using nitrocefin disk.Results From 2015 to 2021,a total of 43 642 strains of Haemophilus species were isolated,accounting for 2.91％of the total clinical isolates and 4.07％of Gram-negative bacteria in CHINET program.Among the 40 437 strains of H.influenzae,66.89％were isolated from children and 33.11％were isolated from adults.More than 90％of the H.influenzae strains were isolated from respiratory tract specimens.The prevalence of β-lactamase was 53.79％in H.influenzae strains.The H.influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults.Overall,779 strains of H.influenzae did not produce β-lactamase but were resistant to ampicillin(BLNAR).Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains.Of the 16 191 M.catarrhalis strains,80.06％were isolated from children and 19.94％isolated from adults.M.catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime,evidenced by resistance rate lower than 2.0％.Conclusions The emergence of antibiotic-resistant H.influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment.Therefore,it is very important to implement antibiotic resistance surveillance for H.influenzae and guide rational antibiotic use.All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H.influenzae.

Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department(hereinafter referred to as outpatients)and inpatient children over time in various hospitals,and to provide laboratory evidence for rational antibiotic use.Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed.Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021.About 17.1％of the strains were isolated from outpatients,primarily group A β-hemolytic Streptococcus,Escherichia coli,and Staphylococcus aureus.Most of the strains(82.9％)were isolated from inpatients,mainly SS.aureus,E.coli,and H.influenzae.The prevalence of methicillin-resistant S.aureus(MRSA)in outpatients(24.5％)was lower than that in inpatient children(31.5％).The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children.The prevalence of vancomycin-resistant Enterococcus faecalis or E.faecium and penicillin-resistant S.pneumoniae was low in either outpatients or inpatient children.S.pneumoniae,β-hemolytic Streptococcus and S.viridans showed high resistance rates to erythromycin.The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children.The prevalence of β-lactamase-producing H.influenzae showed an overall upward trend in children,but lower in outpatients(45.1％)than in inpatient children(59.4％).The prevalence of carbapenem-resistant Klebsiella pneumoniae(CRKpn),carbapenem-resistant Pseudomonas aeruginosa(CRPae)and carbapenem-resistant Acinetobacter baumannii(CRAba)was 14％,11.7％,47.8％in outpatients,but 24.2％,20.6％,and 52.8％in inpatient children,respectively.The prevalence of multidrug-resistant E.coli,K.pneumoniae,Proteus mirabilis,P.aeruginosa and A.baumannii strains was lower in outpatients than in inpatient children.The prevalence of fluoroquinolone-resistant E.coli,ESBLs-producing K.pneumoniae,ESBLs-producing P.mirabilis,carbapenem-resistant E.coli(CREco),CRKpn,and CRPae was lower in children in outpatients than in inpatient children,but the prevalence of CRAba in 2021 was higher than in inpatient children.Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients.The prevalence of MRSA,ESBL,and CRO was higher in inpatient children than in outpatients.Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results.Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the changing antibiotic resistance profiles of E.coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021.Methods Antimicrobial susceptibility was tested for clinical isolates of E.coli according to the unified protocol of CHINET program.WHONET 5.6 and SPSS 20.0 software were used for data analysis.Results Atotal of 289 760 nonduplicate clinical strains ofE.coli were isolated from 2015 to 2021,mainly from urine samples(44.7±3.2)％.The proportion of E.coli strains isolated from urine samples was higher in females than in males(59.0％vs 29.5％).The proportion of E.coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults(16.7％vs 7.8％,0.8％vs 0.1％,both P＜0.05).The isolates from internal medicine department accounted for the largest proportion(28.9±2.8)％with an increasing trend over years.Overall,the prevalence of ESBLs-producing E.coli and carbapenem resistant E.coli(CREco)was 55.9％and 1.8％,respectively during the 7-year period.The prevalence of ESBLs-producing E.coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals.The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021.The prevalence of ESBLs-producing E.coli in tertiary hospitals and children's hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period.The prevalence of CREco in secondary and tertiary hospitals increased slowly.Antibiotic resistance rates changed slowly from 2015 to 2021.Carbapenem drugs(imipenem,meropenem)were the most active drugs amongβ-lactams against E.coli(resistance rate≤2.1％).The resistance rates of E.coli to β-lactam/β-lactam inhibitor combinations(piperacillin-tazobactam,cefoperazone-sulbactam),aminoglycosides(amikacin),nitrofurantoin and fosfomycin(for urinary isolates only)were all less than 10％.The resistance rate of E.coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated,especially for cefazolin and ciprofloxacin,to which the resistance rate of E.coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments(P＜0.05).The E.coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested(excluding tigecycline)than the strains isolated from other departments.The E.coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested(excluding tigecycline,polymyxin B,cefepime and carbapenems)than the strains from secondary hospitals and children's hospitals.Conclusions E.coli is an important pathogen causing clinical infection.More than half of the clinical isolates produced ESBL.The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low.This is an issue of concern.

Objective:To explore differences in the radiation-induced intestinal injury in mice exposed to ultra-high dose rate (FLASH) and conventional-dose-rate (CONV) pulsed X-ray irradiation in order to provide evidence for the application of ultra-high dose rate pulsed X-rays in gastrointestinal radiotherapy.Methods:Using the random number table method, 32 C57BL/6J mice were randomly divided into four groups: a sham irradiation group (SHAM), two conventional dose rate groups (CONV0.067 and CONV0.1), and an ultra-high dose rate group (F215), with each group containing eight mice. All groups, except SHAM, received a single 12 Gy abdominal X-ray irradiation at dose rates of 0.067, 0.1, and 215 Gy/s, respectively. At 3 d post-irradiation, histopathological (hematoxylin-eosin staining, HE staining), immunohistochemical, and Western blot analysis were performed to assess the histopathological markers and oxidative stress indicators of intestinal tissues, as well as relevant proteins involved in signaling pathways.Results:At 3 d post-irradiation, mice in all irradiation groups suffered from varying degrees of intestinal tissue degeneration and necrosis, epithelial cell shedding, villus shortening, and crypt loss ( t = 5.75, 8.79, 5.71, P < 0.05). Regarding oxidative stress, at 3 d post-irradiation, mice in the CONV0.067 and CONV0.1 groups showed significantly lower levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX), glutathione (GSH), and total antioxidant capacity (T-AOC) compared to those in the F215 group ( t = 7.06-10.64, P < 0.01). In contrast, their malondialdehyde (MDA) levels were significantly elevated ( t = 11.06, 8.31, P < 0.01), with no statistical significance observed between them and mice in the F215 group ( P > 0.05). Immunohistochemical and Western blot analyses indicated that at 3 d post-irradiation, mice in the three irradiation groups exhibited an upward trend in the Nrf2 and HO-1 protein levels and a downward trend in the Keap1 protein level compared to those in the SHAM group. Notably, statistical significance was observed between the F215 group and the two conventional dose rate groups ( t = 4.89-20.95, P < 0.05). These result were consistent with the prior changes in antioxidant markers. Conclusions:Ultra-high-dose-rate X-ray irradiation reduces acute RIII by alleviating oxidative stress and modulating the expression of the Keap1-Nrf2-HO-1 signaling pathway.