Objective:To investigate the efficacy and mechanism of botulinum toxin type A (BTX-A) combined with static progressive stretching (SPS) in the treatment of traumatic knee stiffness in rats.Methods:Forty healthy male SD rats aged 8 weeks and weighing 220-300 g, were randomly divided into blank control group ( n=8) and model groups ( n=28) (including injury group, BTX-A group, SPS group and BTX-A+SPS group, with 7 in each group). Hlidebrand′s method was used to construct a traumatic knee stiffness model, with the following main steps: destruction of the joint capsule, Kirschner wire fixation, joint drilling, and removal of the internal fixation at 4 weeks. The blank control group did not receive any treatment and could move freely in the cage. The injury group moved freely after successful modeling. On the day of internal fixation removal, BTX-A was injected into the joint cavity in group BTX-A, SPS treatment was started in the SPS group, BTX-A was injected into the joint cavity and SPS treatment was started in the BTX-A+SPS group. The treatments lasted 16 days. The range of motion (ROM) and joint stiffness were measured before treatment and at 16 days after treatment. At 16 days after treatment, knee joint tissue was collected and the rats were sacrificed, and the articular capsule fibrous tissue proliferation was observed by HE and Masson staining. The expression levels of phosphorylated (p)-Smad2, Smad2, p-Smad3, Smad3, Smad4, transforming growth factor-β1 (TGF-β1), collagen type I, collagen type III, and α-smooth actin (α-SMA) were determined by Western blot. The ratio of phosphorylated protein to total protein was calculated to reflect the phosphorylation level. Results:(1) ROM: Before treatment, the ROM in the blank control group was significantly higher than that in the other groups ( P<0.05), with no significant difference in ROM among the other groups ( P>0.05). At 16 days after treatment, ROM in the injury group, BTX-A group, SPS group, and BTX-A+SPS group was lower than that in the blank control group ( P<0.05), among which ROM in the BTX-A+SPS group was significantly higher than that in the injury group, BTX-A group, and SPS group ( P<0.05). At 16 days after treatment, there was no significant difference in ROM before and after treatment in the blank control group ( P>0.05), and ROM in the other groups was significantly increased compared with that before treatment ( P<0.01). (2) Joint stiffness: At 16 days after treatment, the joint stiffness levels in the injury group, the BTX-A group, and the SPS group were (0.95±0.24)N·cm/°, (0.86±0.22)N·cm/°, and (0.65±0.09)N·cm/° respectively, which were significantly lower than (0.36±0.03)N·cm/° in the blank control group ( P<0.05). The joint stiffness level of the BTX-A+SPS group was (0.49±0.04)N·cm/°, which was not significantly different from that in the blank control group ( P>0.05), but was significantly lower than those in the injury group, BTX-A group, and SPS group ( P<0.05). (3) Fibrous tissue proliferation: at 16 days after treatment, the joint capsular structure in the blank control group was complete and clear, the fibers were arranged in order, and there was no obvious fibrous tissue proliferation. The pathological changes in the injury group were the most serious, with a large number of synovial fibrous tissue proliferation, significantly increased blood vessels in the tissue, and inflammatory cell infiltration. Compared with the SPS group and BTX-A group, the lesions in BTX-A+SPS group were milder, with only slight increase in the number of synovial cells but no obvious vascular proliferation or lymphocytes, and the overall lesions were the least severe. (4) Protein expression: the ratios of p-Smad2/Smad2 in the injury group, BTX-A group and SPS group were 1.552±0.234, 1.328±0.272 and 1.194±0.277 respectively, which were higher than 0.794±0.082 in the blank control group ( P<0.05). The ratio of p-Smad2/Smad2 in the BTX-A+SPS group was 1.013±0.123, which was not significantly different from those in the blank control group, BTX-A group or SPS group ( P>0.05), but was lower than that in the injury group ( P<0.05). At 16 days after treatment, the p-Smad3/Smad3 ratios in the injury group, BTX-A group, SPS group and BTX-A+SPS group were 2.272±0.309, 1.664±0.285, 1.381±0.276 and 1.003±0.060 respectively, which were higher than 0.515±0.051 in the blank control group ( P<0.05). The p-Smad3/Smad3 ratio in the BTX-A+SPS group was significantly lower than those in the injury group, BTX-A group and SPS group ( P<0.05). At 16 days after treatment, the level of Smad4 in the injury group (1.001±0.015) was higher than 0.294±0.076 in the blank control group ( P<0.05). However, there was no significant difference between the BTX-A group (0.664±0.051), SPS group (0.833±0.045), BTX-A+SPS group (0.467±0.068) or the blank control group ( P>0.05). The level of Smad4 in the BTX-A+SPS group was significantly lower than those in the injury group, BTX-A group and SPS group ( P<0.05). At 16 days after treatment, the level of TGF-β1 in the injury group (1.004±0.407) was higher than 0.269±0.122 in the blank control group ( P<0.05), while there was no significant difference between the BTX-A group (0.564±0.194), SPS group (0.422±0.086) and BTX-A+SPS group (0.347±0.161) and the blank control group ( P>0.05). The level of TGF-β1 in the BTX-A+SPS group was significantly lower than those in the injury group, BTX-A group and SPS group ( P<0.05). At 16 days after treatment, the level of type I collagen in the injury group was 0.999±0.170, higher than 0.299±0.139 in the blank control group ( P<0.05), while there was no significant difference between the BTX-A group (0.542±0.278), SPS group (0.561±0.165), and BTX-A+SPS group (0.537±0.045) and the blank control group ( P>0.05). The level of collagen type I in the BTX-A+SPS group was significantly lower than those in the injury group, BTX-A group, and SPS group ( P<0.05). At 16 days after treatment, the level of type III collagen in the injury group was 1.002±0.126, higher than 0.239±0.106 in the blank control group ( P<0.05), while there was no significant difference between the BTX-A group (0.661±0.062), SPS group (0.595±0.062), and BTX-A+SPS group (0.504±0.269) and the blank control group ( P>0.05). The level of collagen type III in the BTX-A+SPS group was significantly lower than those in the injury group, BTX-A group, and SPS group ( P<0.05). At 16 days after treatment, the level of α-SMA in the injury group was 0.998±0.074, higher than 0.130±0.023 in the blank control group ( P<0.05), while there was no significant difference between the BTX-A group (0.358±0.060), SPS group (0.432±0.230), and BTX-A+SPS group (0.293±0.135) and the blank control group ( P>0.05). The level of α-SMA in the BTX-A+SPS group was significantly lower than those in the injury group, BTX-A group and SPS group ( P<0.05). Conclusions:Compared with single treatment, the combination of BTX-A and SPS demonstrates significantly greater efficacy in the treatment of traumatic knee stiffness in rats. This combined approach not only enhances joint mobility and elasticity but also effectively inhibits joint capsule fibrosis. The underlying mechanism may involve the further suppression of TGF-β1 expression in the joint capsule, leading to reduced phosphorylation levels of Smad2 and Smad3. This, in turn, inhibits the binding of Smad2 and Smad3 to the Smad4 receptor, ultimately downregulating the expression of the downstream proteins of the TGF-β/Smad signaling pathway, such as collagen type I, collagen type III and α-SMA.

Objective:To evaluate the early outcomes of total hip arthroplasty (THA) and discuss the revisions post THA in the treatment for Kashin-Beck disease (KBD) with severe hip problems.Methods:This retrospective cohort study enrolled 50 patients (64 hips) with a mean age of 52.4±8.7 years, including 25 male patients and 25 female patients (36 left hips and 28 right hips), who were diagnosed as KBD with hip problems and received THA at Arthritis Clinical and Research Centre, Peking University People's Hospital from October 2019 to January 2024. The leg length discrepancy (LLD), femoral offset (FO), abduction angle and anteversion angle were calculated preoperatively and one week post-operation. The postoperative radiological indexes and the functional outcomes in the last follow-up were compared with the preoperative assessment.Results:The surgical duration was 105(80, 120) min and the bleeding amount was 300(200, 400) ml. All the cases were followed up for an average of 37 months (ranging from 21 to 44 months). Significant differences were found on postoperative radiological images, with LLD improving to 0.50±0.78 cm from a preoperative value of -1.36±0.79 cm, and FO increasing to 3.28±1.01 cm from 2.72±0.83 cm ( P<0.05). The mean postoperative abduction angle and anteversion angle were 42.5°±7.7° and 15.1°±5.9°, respectively. A total of 71.8% and 95.3% hips fell within the Lewinnek safe zones of abduction angle and anteversion angle, respectively. In terms of functional outcomes, the average range of motion improved significantly to 185°(173°, 210°) from a preoperative value of 99°(76°, 123°), and the Harris Hip Score increased from 35(26, 43) preoperatively to 70(63, 80) postoperatively ( P<0.05). During the follow-up, there were complications for two cases of femoral stem loosening, one case of periprosthetic femoral fracture, one case of hip dislocation, and one case of acetabular component loosening with hip subluxation. Additionally, seven patients exhibited Trendelenburg gait. A total of five hips required revision surgery due to severe complications, including two cases of femoral stem loosening, one case of periprosthetic femoral fracture, one case of hip dislocation, and one case of acetabular component loosening with subluxation. Conclusions:Patients with KBD demonstrated significant early improvements in both radiological and functional outcomes following THA.

Dark plum can be used to treat symptoms such as consumptive thirst due to deficiency-heat and chronic cough due to lung deficiency.Its active ingredients have auxiliary effects on lowering blood glucose,antibacterial and anti-inflammatory activities.Insulin resistance is mainly characterized by the weakening of the physiological effects of insulin in the body,with a relatively complex mechanism that can lead to various metabolic-related diseases and seriously affect health.The active ingredients of dark plum can improve insulin resistance by regulating insulin signaling pathways,endoplasmic reticulum stress,antioxidant stress,inflammatory signaling pathways,levels of related inflammatory mediators,and free fatty acid levels.By reviewing the relevant literature on the improvement of insulin resistance by the active ingredients of dark plum,this article summarizes and analyzes its mechanism of action,aiming to provide new ideas and scientific evidence for in-depth research on insulin resistance and the development and application of drugs.

This study aimed to explore the effects and mechanisms of total extracts from Anthriscus sylvestris on pulmonary hypertension in rats. Sixty male SD rats were divided into normal(NC) group, model(M) group, positive drug sildenafil(Y) group, low-dose A. sylvestris(ES-L) group, medium-dose A. sylvestris(ES-M) group, and high-dose A. sylvestris(ES-H) group. On day 1, rats were intraperitoneally injected with monocrotaline(60 mg·kg~(-1)) to induce pulmonary hypertension, and the rat model was established on day 28. From days 15 to 28, intragastric administration of the respective treatments was performed. After modeling and treatment, small animal echocardiography was used to detect the right heart function of the rats. Arterial blood gas was measured using a blood gas analyzer. Hematoxylin and eosin(HE) staining and Masson staining were performed to observe cardiopulmonary pathological damage. Flow cytometry was used to detect apoptosis in the lung and myocardial tissues and reactive oxygen species(ROS) levels. Western blot was applied to detect the expression levels of transforming growth factor-β1(TGF-β1), phosphorylated mothers against decapentaplegic homolog 3(p-Smad3), Smad3, tissue plasminogen activator(t-PA), and plasminogen activator inhibitor-1(PAI-1) in lung tissue. A blood routine analyzer was used to measure inflammatory immune cell levels in the blood. Enzyme-linked immunosorbent assay(ELISA) was used to detect the expression levels of P-selectin and thromboxane A2(TXA2) in plasma. The results showed that, compared with the NC group, right heart hypertrophy index, right ventricular free wall thickness, right heart internal diameter, partial carbon dioxide pressure(PaCO_2), apoptosis in cardiopulmonary tissue, and ROS levels were significantly increased in the M group. In contrast, the ratio of pulmonary blood flow acceleration time(PAT)/ejection time(PET), right cardiac output, change rate of right ventricular systolic area, systolic displacement of the tricuspid ring, oxygen partial pressure(PaO_2), and blood oxygen saturation(SaO_2) were significantly decreased in the M group. After administration of the total extract of A. sylvestris, right heart function and blood gas levels were significantly improved, while apoptosis in cardiopulmonary tissue and ROS levels significantly decreased. Further testing revealed that the total extract of A. sylvestris significantly decreased the levels of interleukin-1β(IL-1β), interleukin-6(IL-6), and PAI-1 proteins in lung tissue, while increasing the expression of t-PA. Additionally, the extract reduced the levels of inflammatory cells such as leukocytes, lymphocytes, granulocytes, and monocytes in the blood, as well as the levels of P-selectin and TXA2 in plasma. Metabolomics results showed that the total extract of A. sylvestris significantly affected metabolic pathways, including arginine biosynthesis, tyrosine metabolism, and taurine and hypotaurine metabolism. In conclusion, the total extract of A. sylvestris may exert an anti-pulmonary hypertension effect by inhibiting the TGF-β1/Smad3 signaling pathway, thereby alleviating immune-inflammatory responses and thrombosis.
Animals ; Male ; Smad3 Protein/metabolism* ; Transforming Growth Factor beta1/metabolism* ; Rats, Sprague-Dawley ; Rats ; Signal Transduction/drug effects* ; Hypertension, Pulmonary/genetics* ; Thrombosis/immunology* ; Drugs, Chinese Herbal/administration & dosage* ; Humans ; Apoptosis/drug effects*

Through evidence mapping, this paper systematically summarized the research evidence on the use of traditional Chinese medicine(TCM) in treating renal anemia, displaying the distribution of evidence in this field. A systematic search was conducted across databases, including CNKI, Wanfang, VIP, SinoMed, Springner, PubMed, Engineering Village, and Web of Science, targeting studies published up to June 30, 2024. The research evidence was summarized and displayed through a combination of graphs, tables, and text. A total of 264 interventional studies, 37 observational studies, and 7 systematic reviews were included. The annual publication volumes related to TCM treatment in renal anemia showed an overall upward trend, with most studies involving sample sizes between 60 and 120 participants(224 articles, 74.42%). Intervention measures were categorized into 21 types, with oral TCM decoctions being the most common medicine(171 times, 56.81%). The use of self-made prescriptions was the most common TCM intervention method. The intervention duration was mainly between 8 weeks and 3 months(239 articles, 79.40%). The most frequently reported TCM syndrome was spleen and kidney Qi deficiency. The top 2 outcome indicators were the anemia indicators and renal injury/renal function markers. However, several issues were identified in these studies, such as insufficient attention to the sources, social/geographical information, and temporal continuity of research subjects in observational research. Randomized controlled trials mostly had a high risk of bias, mainly due to issues such as randomization bias, blinding bias, and failure to register research protocols. The methodology quality of systematic reviews was generally low, mainly due to inadequate inclusion of literature, failure to specify funding sources, and lack of pre-registrations. While the report quality of systematic review was acceptable, there were significant gaps in the reporting of protocols, registration, and funds. The results show that these issues affect the quality of research and the reliability of findings on TCM in treating renal anemia, underscoring the need to address them to conduct higher-quality research and provide more reliable medical evidence for TCM in treating renal anemia.
Humans ; Anemia/drug therapy* ; Drugs, Chinese Herbal/therapeutic use* ; Medicine, Chinese Traditional ; Kidney Diseases/drug therapy*

The aim of this study was to investigate the improvement effect of Wenpi Pills(WPP) on non-alcoholic fatty liver disease(NAFLD). The experiment was divided into two parts, using C57BL/6 mouse models induced by a high-fat diet(HFD) and a methionine and choline deficiency diet(MCD). The HFD-induced experiment lasted for 16 weeks, while the MCD-induced experiment lasted for 6 weeks. Mice in both parts were divided into four groups: control group, model group, low-dose WPP group(3.875 g·kg~(-1), WPP＿L), and high-dose WPP group(15.5 g·kg~(-1), WPP＿H). After sample collection from the HFD-induced mice, lipid content in the serum and liver, liver function indexes in the serum, and hepatic pathology were examined. Real-time fluorescent quantitative reverse transcription PCR(qRT-PCR) was used to detect the expression of lipid-related genes. After sample collection from the MCD-induced mice, serum liver function indexes and inflammatory factors were measured, and hepatic pathology and lipid changes were analyzed by hematoxylin-eosin(HE) staining and widely targeted lipidomic profiling, respectively. The results from the HFD-induced experiment showed that, compared with the HFD group, WPP administration significantly reduced the levels of aspartate aminotransferase(AST), alanine aminotransferase(ALT), triglyceride(TG), and total cholesterol(TC) in the serum, with the WPP＿H group showing the most significant improvement. HE staining results indicated that, compared with the HFD group, WPP treatment improved the morphology of white adipocytes, reducing their size, and alleviated hepatic steatosis and lipid droplet accumulation. The qRT-PCR results suggested that WPP might increase the mRNA expression of liver cholesterol-converting genes, such as liver X receptor α(LXRα) and cytochrome P450 family 27 subfamily A member 1(CYP27A1), as well as lipid consumption genes like peroxisome proliferator-activated receptor α(PPARα) and adenosine mono-phosphate-activated protein kinase(AMPK). Meanwhile, WPP decreased the mRNA expression of lipid synthesis genes, including fatty acid synthetase(FAS), stearoyl-CoA desaturase 1(SCD1), and sterol regulatory element-binding protein 1c(SREBP-1c), thereby reducing liver lipid accumulation. The results from the MCD-induced experiment showed that, compared with the MCD group, WPP administration reduced the levels of ALT, AST, and inflammatory factors in the serum, thereby alleviating liver injury and the inflammatory response. HE staining of liver tissue indicated that WPP effectively improved hepatic steatosis. Non-targeted lipidomics analysis showed that WPP improved lipid metabolism disorders in the liver, mainly by affecting the metabolism of TG and cholesterol esters. In conclusion, WPP can improve hepatic lipid accumulation in NAFLD mice induced by both HFD and MCD. This beneficial effect is primarily achieved by alleviating liver injury and inflammation, as well as regulating lipid metabolism.
Animals ; Non-alcoholic Fatty Liver Disease/genetics* ; Lipid Metabolism/drug effects* ; Mice ; Mice, Inbred C57BL ; Drugs, Chinese Herbal/administration & dosage* ; Male ; Diet, High-Fat/adverse effects* ; Liver/drug effects* ; Humans ; Disease Models, Animal ; Methionine

This study investigated the protective effect of arbutin(Arb) in yam on lipopolysaccharide(LPS)-induced acute lung injury(ALI) in a mouse model and revealed its possible mechanism of action by metabolomics technology, providing a theoretical basis for clinical treatment of ALI. SPF BALB/c mice were randomly divided into normal control group, model group, resveratrol(Rv)-positive control group, Arb low-dose(15 mg·kg~(-1)) group, and Arb high-dose(30 mg·kg~(-1)) group. The LPS-induced ALI model was established in all groups except the normal control group. Hematoxylin-eosin(HE) staining, TUNEL staining, and WBP whole-body non-invasive pulmonary function testing were used to evaluate the degree of lung tissue damage and lung function changes. Enzyme-linked immunosorbent assay(ELISA) was used to detect the level of inflammatory factors in lung tissue. Flow cytometry was used to analyze the M1/M2 polarization status of macrophages in lung tissue. Western blot was used to detect the expression levels of the TLR4 signaling pathway and related apoptotic proteins. Liquid chromatograph-mass spectrometer(LC-MS) metabolomics was used to analyze the changes in serum metabolic profile after Arb intervention. The results showed that Arb pretreatment significantly alleviated LPS-induced lung tissue injury, improved lung function, reduced the levels of pro-inflammatory factors(IL-6, TNF-α, IL-18, and IL-1β), and regulated the polarization status of M1/M2 macrophages. In addition, Arb inhibited the activation of the TLR4 signaling pathway, reduced the expression of pro-apoptotic proteins such as Bax, caspase-3, and caspase-9, up-regulated the level of Bcl-2 protein, and inhibited apoptosis of lung cells. Metabolomic analysis showed that Arb significantly improved LPS-induced metabolic abnormalities, mainly involving key pathways such as galactose metabolism, phenylalanine metabolism, and lipid metabolism. In summary, Arb can significantly reduce LPS-induced ALI by regulating the release of inflammatory factors, inhibiting the activation of the TLR4 signaling pathway, improving metabolic disorders, and regulating macrophage polarization, indicating that Arb has potential clinical application value.
Animals ; Acute Lung Injury/chemically induced* ; Mice ; Mice, Inbred BALB C ; Arbutin/administration & dosage* ; Male ; Toll-Like Receptor 4/immunology* ; Apoptosis/drug effects* ; Lung/metabolism* ; Signal Transduction/drug effects* ; Protective Agents/administration & dosage* ; Humans ; Macrophages/immunology* ; Drugs, Chinese Herbal/administration & dosage*

OBJECTIVE: To explore the co-morbid influencing factors of postmenopausal osteoporosis(PMOP) and dyslipidemia, and to provide evidence-based basis for clinical co-morbidity management. METHODS: Based on the 2017 to 2018 Beijing community cross-sectional survey data, PMOP patients were included and divided into the dyslipidemia group and the uncomplicated dyslipidemia group according to whether they were comorbid with dyslipidemia. Demographic characteristics, living habits and disease history were collected through questionnaires, and bone mineral density and bone metabolism biomarkers (osteocalcin, blood calcium, serum typeⅠprocollagen N-terminal prepeptide, etc.) were detected on site. Co-morbidity risk factors were analyzed using binary logistic regression. RESULTS: Three hundred and twenty patients with PMOP were included, including the comorbid group (75 patients) and the uncomplicated group (245 patients). The results showed that history of cardiovascular disease [OR=1.801, 95%CI(1.003, 3.236), P=0.049], history of cerebrovascular disease [OR=2.923, 95%CI(1.460, 5.854), P=0.002], frying and cooking methods[OR=5.388, 95%CI(1.632, 17.793), P=0.006], OST results[OR=0.910, 95%CI(0.843, 0.983), P=0.016], and blood Ca results [OR=60.249, 95%CI(1.862, 1 949.926), P=0.021] were the influencing factors of PMOP complicated with dyslipidemia. CONCLUSION Focus should be placed on the influencing factors of PMOP and dyslipidemia co-morbidities, with emphasis on multidimensional assessment, combining lifestyle interventions with bone metabolism marker monitoring to optimize co-morbidity management.
Humans ; Dyslipidemias/epidemiology* ; Female ; Middle Aged ; Osteoporosis, Postmenopausal/metabolism* ; Aged ; Cross-Sectional Studies ; Risk Factors ; Bone Density

OBJECTIVES: To evaluate the safety and efficacy of thiotepa (TT)-containing conditioning regimens for allogeneic hematopoietic stem cell transplantation (HSCT) in children with inborn errors of immunity (IEI). METHODS: Clinical data of 22 children with IEI who underwent HSCT were retrospectively reviewed. Survival after HSCT was estimated using the Kaplan-Meier method. RESULTS: Nine patients received a traditional conditioning regimen (fludarabine + busulfan + cyclophosphamide/etoposide) and underwent peripheral blood stem cell transplantation (PBSCT). Thirteen patients received a TT-containing modified conditioning regimen (TT + fludarabine + busulfan + cyclophosphamide), including seven PBSCT and six umbilical cord blood transplantation (UCBT) cases. Successful engraftment with complete donor chimerism was achieved in all patients. Acute graft-versus-host disease occurred in 12 patients (one with grade III and the remaining with grade I-II). Chronic graft-versus-host disease occurred in one patient. The incidence of EB viremia in UCBT patients was lower than that in PBSCT patients (P<0.05). Over a median follow-up of 36.0 months, one death occurred. The 3-year overall survival (OS) rate was 100% for the modified regimen and 88.9% ± 10.5% for the traditional regimen (P=0.229). When comparing transplantation types, the 3-year OS rates were 100% for UCBT and 93.8% ± 6.1% for PBSCT (P>0.05), and the 3-year event-free survival rates were 100% and 87.1% ± 8.6%, respectively (P>0.05). CONCLUSIONS TT-containing conditioning for allogeneic HSCT in children with IEI is safe and effective. Both UCBT and PBSCT may achieve high success rates.
Humans ; Retrospective Studies ; Transplantation Conditioning/methods* ; Thiotepa/therapeutic use* ; Hematopoietic Stem Cell Transplantation/adverse effects* ; Male ; Female ; Child, Preschool ; Infant ; Child ; Transplantation, Homologous ; Graft vs Host Disease ; Adolescent

This study was aimed at identifying the pathogenic bacteria responsible for the death of a young tiger at the Fujian Meihua Mountain South China Tiger Breeding Research Institute.Tissue samples from the lungs,liver,and intestines of the deceased tiger were collected,and the bacteria were cultured inasterile environment.The bacterial strains were characterized according to their morphological and molecular biological properties,including assessment of virulence genes and antibiotic resistance genes,mouse lethality tests,and antibiotic susceptibility evaluations.A predominant bacterial strain isolated from the liver of the deceased tiger was identified as enterotoxigenic Escherichia coli(ETEC)strain Tiger22513F.Phylogenetic analysis of the 16S rRNA gene revealed that the Tiger22513F strain exhibited close genetic similarity to the reference strain ETEC(MF919609.1),with 99.9%nucleotide similarity,and resided on the same evolutionary branch.The Tiger22513F strain contained 11 antibiotic resistance genes(tetA,sul1,sul3,cmlA,floR,blaTEM,blaSHV,blaCMY-2,qnrA,qnrS,and qnrD)along with five virulence genes(VT1,fyuA,tsh,iucD,and ST).Mouse lethality tests indicated significant pathogenicity toward mice,affecting primarily the lungs,liver,and intestines.Antibiotic susceptibility testing demonstrated that this strain exhibited resistance to various classes of beta-lactam antibiotics,as well as quinolones and aminoglycosides.This investigation successfully isolated a multi-drug resistant enterotoxigenic Escherichia coli strain with pronounced pathogenicity from the liver of a deceased tiger;thus providing valuable scientific insights for clinical diagnosis,as well as prevention and control measures,against ETEC infections in South China tigers.