1.Qishen Granules Attenuate Doxorubicin-induced Cardiotoxicity via TBC1D15-mediated Mitochondria-lysosome Contacts
Nannan TAN ; Weili LI ; Guanjing LING ; Yan WEI ; Linghui LU ; Yong WANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(21):99-109
ObjectiveTo verify the protective effect and pharmacological mechanism of Qishen granules against doxorubicin-induced cardiotoxicity, thus providing a basis for developing new drug options for clinical treatment of cardio-oncology disease. MethodsFifty mice were randomly assigned into a normal group (n=10) and a modeling group (n=40). The model was established by intravenous injection of doxorubicin (5 mg·kg-1) via the tail vein, once a week for 4 consecutive weeks. The normal group was injected with an equal volume of normal saline during the same period. The modeled mice were further assigned into four groups: doxorubicin (no drug control), low-dose (3.33 mg·kg-1) Qishen granules, high-dose (6.67 mg·kg-1) Qishen granules, and enalapril (15 mg·kg-1). Mice were administrated with corresponding drugs by gavage for 4 consecutive weeks. At the end of the experiment, echocardiography, histopathological staining, and live-cell imaging were employed to determine relevant indicators, on the basis of which the protective effect of Qishen granules against doxorubicin-induced cardiotoxicity was evaluated. ResultsCompared with the normal group, doxorubicin treatment reduced the left ventricular ejection fraction (LVEF) (P<0.05) and caused pathological changes including disarrangement of cardiomyocytes, increased cell spacing, cardiomyocyte hypertrophy, and increased apoptosis in the heart tissue. Meanwhile, doxorubicin prolonged the mitochondria-lysosome contact time, downregulated the expression of TBC1 domain family member 15 (TBC1D15) (P<0.01), upregulated the levels of microtubule-associated protein 1 light chain 3 (LC3) and sequestosome 1 (p62) (P<0.01), and induced mitochondrial cristae breakage, resulting in mitochondrial dysfunction. Compared with the doxorubicin group, intervention with Qishen granules reversed the above indicators. It not only increased the LVEF (P<0.01) and alleviated pathological damage to the heart, but also upregulated the expression of TBC1D15 (P<0.01), shortened the mitochondria-lysosome contact time (P<0.05), and downregulated the protein levels of LC3 and p62. When TBC1D15 in cells was knocked down, the autophagy-activating and mitochondrion-protecting effects of Qishen granules partially disappeared. ConclusionQishen granules upregulate the expression of TBC1D15 to shorten the mitochondria-lysosome contact time, thereby activating autophagy and ultimately exerting a protective effect against doxorubicin-induced cardiotoxicity.
2.Qishen Granules Attenuate Doxorubicin-induced Cardiotoxicity via TBC1D15-mediated Mitochondria-lysosome Contacts
Nannan TAN ; Weili LI ; Guanjing LING ; Yan WEI ; Linghui LU ; Yong WANG
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(21):99-109
ObjectiveTo verify the protective effect and pharmacological mechanism of Qishen granules against doxorubicin-induced cardiotoxicity, thus providing a basis for developing new drug options for clinical treatment of cardio-oncology disease. MethodsFifty mice were randomly assigned into a normal group (n=10) and a modeling group (n=40). The model was established by intravenous injection of doxorubicin (5 mg·kg-1) via the tail vein, once a week for 4 consecutive weeks. The normal group was injected with an equal volume of normal saline during the same period. The modeled mice were further assigned into four groups: doxorubicin (no drug control), low-dose (3.33 mg·kg-1) Qishen granules, high-dose (6.67 mg·kg-1) Qishen granules, and enalapril (15 mg·kg-1). Mice were administrated with corresponding drugs by gavage for 4 consecutive weeks. At the end of the experiment, echocardiography, histopathological staining, and live-cell imaging were employed to determine relevant indicators, on the basis of which the protective effect of Qishen granules against doxorubicin-induced cardiotoxicity was evaluated. ResultsCompared with the normal group, doxorubicin treatment reduced the left ventricular ejection fraction (LVEF) (P<0.05) and caused pathological changes including disarrangement of cardiomyocytes, increased cell spacing, cardiomyocyte hypertrophy, and increased apoptosis in the heart tissue. Meanwhile, doxorubicin prolonged the mitochondria-lysosome contact time, downregulated the expression of TBC1 domain family member 15 (TBC1D15) (P<0.01), upregulated the levels of microtubule-associated protein 1 light chain 3 (LC3) and sequestosome 1 (p62) (P<0.01), and induced mitochondrial cristae breakage, resulting in mitochondrial dysfunction. Compared with the doxorubicin group, intervention with Qishen granules reversed the above indicators. It not only increased the LVEF (P<0.01) and alleviated pathological damage to the heart, but also upregulated the expression of TBC1D15 (P<0.01), shortened the mitochondria-lysosome contact time (P<0.05), and downregulated the protein levels of LC3 and p62. When TBC1D15 in cells was knocked down, the autophagy-activating and mitochondrion-protecting effects of Qishen granules partially disappeared. ConclusionQishen granules upregulate the expression of TBC1D15 to shorten the mitochondria-lysosome contact time, thereby activating autophagy and ultimately exerting a protective effect against doxorubicin-induced cardiotoxicity.
3.Application and dosimetric study of different modal-based images in delineation for target area of liver cancer
Wei LU ; Feifei ZHANG ; Qian SUN ; Lei ZHANG ; Wei LI ; Yang HAN ; Nannan QIN ; Xin CHEN ; Shimiao DUAN
China Medical Equipment 2025;22(7):10-15
Objective:To compare the differences of three-dimensional computed tomography(3DCT),four-dimensional computed tomography(4DCT),and multi-parametric magnetic resonance(MR)sequences of the radiotherapy for liver cancer in delineation for target area,and analyze which MR sequence was more accurate in assisting CT image to delineate the target area,and design respectively reverse intensity modulated radiotherapy plan,and compare the dosimetric parameters of the target areas of receiving radiotherapy and normal liver tissue.Methods:This retrospective study was conducted to analyze radiotherapy data from case data of 18 patients with hepatocellular carcinoma(HCC)who admitted to the First Affiliated Hospital of Bengbu Medical University between August 2023 and June 2024.These data included 10 respiratory phases in 3DCT and 4DCT,and free-breathing sequence(MR-FB),diaphragm navigation sequence(MR-NAVI),and breath-hold(MR-BH)sequence of multi-parametric MRI,and the gross tumor volumes(GTVs)of them were delineated,which were respectively 5 modal images and liver contours included GTV3D,GTV4D,GTVMR-FB,GTVMR-NAVI,and GTVMR-BH.Pinnacle3 9.8 treatment plan system(TPS)was applied to conduct registration and fusion for image by using mutual information method.The 3DCT(GTV3D)was used as reference image to compare the volume of target area,and the displacement of mass center with other 4 kinds of images.The volume difference(VD),overlap ratio(OR),Dice similarity coefficient(DSC),and Jaccard index(JAC)were used to assess the differences among different target area.The indicators of plan evaluation included conformity index(CI),homogeneity index(HI),GTV doses(D2%,D98%,Dmean),and the exposure dose of normal tissue of liver.Results:In images of five modalities,the GTV median volumes were respectively 28.83,33.10,26.75,25.05,and 22.65 cm3.In images of five modalities,the median volume of liver were respectively 1293.46,1483.09,1213.81,1195.69,and 1141.02 cm3.Compared with other 3 target areas,the displacement of GTVMR-BH was the smallest on head-foot direction,with statistically significant differences among them(Z=-2.305,-2.307,-2.134,P<0.05).The OR,DSC,and JAC values of GTV4D were significantly better than these of GTVMR-FB,GTVMR-NAVI,and GTVMR-BH(ZOR=-2.911,-3.006,-3.195,ZDSC=-2.726,-2.215,-2.556,ZJAC=-2.556,-2.704,-2.953,P<0.05).The VD value of GTVMR-FB was better than that of GTV4D,GTVMR-NAVI,and GTVMR-BH,with statistically significant(Z=-2.675,-2.817,-2.580,P<0.05).Additionally,the OR,DSC,and JAC values of GTVMR-FB and GTVMR-NAVI were better than those of GTVMR-BH,with statistically significant(ZOR=-2.859,-2.817,ZDSC=-2.184,-2.783,ZJAC=-2.385,-2.783,P<0.05).All five plans met clinical dose requirements.Friedman test showed there was no statistically significant differences in dosimetric parameters of target area among different plans(P>0.05).However,compared to the PTV3D plan,the PTVMR-FB,PTVMR-NAVI,and PTVMR-BH plans resulted in lower levels in mean dose(Dmean)of liver and volume parameters(V5,V10,V20,V30)of various doses,with statistically significant differences(Dmean:Z=-2.433,-2.307,-2.807,ZV5=-2.512,-2.433,-2.652,ZV10=-2.433,-2.536,-2.968,ZV20=-2.536,-2.652,-2.807,ZV30=-2.611,-2.652,-2.968,P<0.05).Conclusion:In actually clinical application,MR-NAVI and 4DCT also can be adopted to assist 3DCT to delineate target area besides MR-FB sequence that is conventionally used in MR location,thus can enhance precision of delineation,and optimize radiotherapy plan,and decrease exposure dose of normal liver tissue.
4.Visualization analysis of the application of external traditional Chinese medicine treatments in diabetic foot ulcer based on CiteSpace
Ke DAI ; Nannan ZHENG ; Wenjiao ZHU ; Xiang GAO ; Wei SHEN
China Modern Doctor 2025;63(24):44-49
Objective Based on CiteSpace,this study analyzes the current research status,hotspots,and trends in the field of external traditional Chinese medicine treatments for diabetic foot ulcer,aiming to support the optimization of clinical practice and guide future research directions.Methods Literature related to external traditional Chinese medicine treatments for diabetic foot ulcer was retrieved using CiteSpace software from China National Knowledge Infrastructure,Wanfang Data Knowledge Service Platform,VIP,and SinoMed databases.The analysis was conducted from multiple perspectives,including keywords,authors,and institutions.Results A total of 1807 articles were included.The annual publication volume showed a trend of initial increase followed by a decline,reaching a peak in 2014 with 137 articles,and then maintaining a relatively high level.Research institutions demonstrated limited collaboration,forming small-scale cooperative clusters.Research hotspots primarily focused on the development of external treatment techniques and the integration of Chinese and Western medicine.The research trend reveals a shift from single treatment approaches to comprehensive therapies,integrating with modern medical technologies and gradually moving toward precision medicine.Conclusion Visual analysis intuitively reveals research hotspots and frontiers in this field.In the future,the development of standardized protocols through evidence-based medicine and strengthened collaboration among institutions could promote the advancement of external traditional Chinese medicine treatments in the management of diabetic foot ulcer.
5.The mediating effect of protracted abstinence duration and impulsivity in heroin addicts
Nannan CAO ; Jiajie CHEN ; Zhidong WANG ; Liyang DANG ; Jia ZHU ; Yongbin LI ; Wei WANG
Journal of Practical Radiology 2025;41(8):1267-1270
Objective To explore the impact of the duration of protracted abstinence(PA)treatment on the level of impulsivity among heroin addicts and to analyze the mediating effect of impulsive cognition between abstinence duration and impulsive behavior.Methods Thirty-six heroin addicts undergoing PA treatment(PA group)and forty matched healthy controls(HC)(HC group)were recruited.Demographic information was collected via questionnaires,and impulsive cognition assessments were conducted.Participants completed the GO/NOGO task to collect data on impulsive behavior.Intergroup differences were compared using the independent sample t-test,and multiple linear regression analysis and mediating effect analysis were performed on the PA group.Results The PA group exhibited significantly higher scores on motor impulsivity,non-planning impulsivity,and total impulsivity compared to the HC group.Additionally,the PA group demonstrated significantly increased NOGO error rate during the GO/NOGO task compared to the HC group(P<0.001).Multiple linear regression analysis revealed that abstinence duration had a significant negative impact on total impulsivity and non-planning impulsivity(P<0.001).Mediating effect analysis found a partial mediation effect of total impulsivity between abstinence duration and NOGO error rate(P<0.001).Conclusion The PA treatment has a significant impact on the level of impulsivity among heroin addicts.Impulsive cognition play a partial mediating role between abstinence duration and impulsive behavior.These results provide an important theoretical and practical basis for optimizing PA treatment programs.
6.The role of leucine-rich α2 glycoprotein in evaluating mucosal healing in small bowel Crohn′s disease
Yuanyuan FANG ; Chenyu ZHANG ; Nannan ZHU ; Wei HAN ; Jing HU ; Juan WU ; Peipei ZHANG ; Qiuyuan LIU ; Hao DING ; Qiao MEI
Chinese Journal of Digestion 2025;45(5):317-323
Objective:To investigate the correlation between leucine-rich α2 glycoprotein (LRG) and endoscopic activity in patients with Crohn′s disease (CD), based on the assessment of inflammation in small intestinal lesion by double-balloon enteroscope (DBE).Methods:From 15 August 2022 to 22 August 2023, the clinical data of 139 patients with small bowel CD diagnosed by DBE at the First Affiliated Hospital of Anhui Medical University were prospectively collected, which included fecal calprotectin (FC), C-reactive protein (CRP), white blood cell count, hemoglobin, albumin, Crohn′s disease activity index (CDAI), and simple endoscopic score for Crohn′s disease (SES-CD). According to the SES-CD, endoscopic activity was classified as mucosal healing (0), endoscopic remission (0 to 2), mild activity (3 to 6), moderate activity (7 to 15), and severe activity (≥16). LRG levels were detected in all patients. Spearman rank correlation was used to analyze the correlation between LRG, clinical biochemical parameters and endoscopic scores. Receiver operating characteristic curve (ROC) was performed to determine the optimal cut-off value of LRG for evaluating endoscopic mucosal healing. Mann-Whitney U test, Kruskal-Wallis H test, and Bonferroni corrected test were used for statistical analysis. Results:Among 139 patients with small bowel CD, the LRG level was 17.3 (13.0, 25.2) mg/L, and SES-CD was 5 (1, 9); 32 patients achieved mucosal healing, 50 patients achieved endoscopic remission; 39 patients had mild activity, 40 patients had moderate activity, and 10 patients had severe activity. The SES-CD was negatively correlated with both hemoglobin and albumin ( r=-0.177 (95% confidence interval, 95% CI: -0.334 to -0.011), -0.293 (95% CI: -0.438 to -0.133)), with statistical significance ( P=0.037, <0.001). The SES-CD was positively correlated with CRP, CDAI, LRG and FC ( r=0.344 (95% CI: 0.188 to 0.482), 0.429 (95% CI: 0.282 to 0.556), 0.525 (95% CI: 0.393 to 0.636), 0.661 (95% CI: 0.556 to 0.745)), with statistical significant (all P<0.001). For the 64 small bowel CD patients with CRP in the normal reference value, SES-CD was positively correlated with CDAI, LRG and FC ( r=0.296 (95% CI: 0.054 to 0.505), 0.364 (95% CI: 0.129 to 0.559), 0.547 (95% CI: 0.348 to 0.699)), with statistical significance ( P=0.017, =0.003, <0.001). The LRG level of patients with endoscopic mucosal healing was significantly lower than that of patients with endoscopic remission (11.5 (10.1, 17.2) mg/L vs. 17.3 (13.4, 23.5) mg/L), with statistical significance ( Z=-3.25, P<0.001). ROC analysis showed that the area under the curve (AUC) of LRG in predicting endoscopic mucosal healing was 0.81 (95% CI: 0.73 to 0.89), with an optimal cut-off value of 15.27 mg/L. The sensitivity, specificity, positive predictive value and negative predictive value were 0.757, 0.718, 0.900 and 0.469, respectively. The accuracy of the combination of LRG and FC (AUC was 0.88, 95% CI: 0.82 to 0.94) in predicting endoscopic mucosal healing was higher than that of LRG alone (AUC was 0.81, 95% CI: 0.73 to 0.89), and the difference was statistically significant ( P=0.011). Conclusion:Based on the results of DBE, LRG may be a reliable biomarker for predicting endoscopic remission and mucosal healing in patients with small bowel CD.
7.Research on risk assessment and dynamic management based on HACCP system for operational safety of medical equipment
Yingming SONG ; Qingyuan LIU ; Yutao CHENG ; Nannan WEI
China Medical Equipment 2025;22(8):130-135
Objective:To study the application effect of the Hazard Analysis and Critical Control Point(HACCP)system in risk assessment and dynamic management of operational safety of medical equipment in surgery rooms.Methods:Based on the HACCP principle,hazard analysis and risk assessment were conducted on the operational safety of equipment in surgery room,and the critical control points were determined,and measures of monitor and management were formulated to conduct whole-process dynamic management for equipment in surgery room.A total of 120 medical equipment in use in the surgery room of Shaanxi Provincial Cancer Hospital from January 2022 to January 2024 were selected.According to random number table method,they were divided into conventional management mode group(60 equipment that received conventional management mode)and dynamic management mode group(60 equipment that received the mode of risk assessment and dynamic management based on HACCP system for operational safety of medical equipment in surgery rooms)to receive different managements.The effect,operational quality,the score of management standardization,and management level for equipment in managing and controlling risk of safety of equipment were compared between two management modes.Results:The average pressure-related injury,electrical injury,extravasation of body fluid,and incidence of unqualified cleaning and disinfection of equipment in the dynamic management mode group were respectively(3.01±1.01)%,(2.65±0.78)%,(1.65±0.64)%and(1.15±0.16)%,all of which were lower than those in the conventional management mode group,and the differences were statistically significant(t=16.311,13.434,12.018,12.629,P<0.05).The average utilization rate,cost-benefit amplification and social benefit amplification of the equipment in the dynamic management mode group were respectively(95.36±2.87)%,(7.98±1.32)%and(10.68±2.36)%,all of which were higher than those in the conventional management mode group,and the average operating rate in the dynamic management mode group was(9.87±1.54)%,which was lower than that in the conventional management mode group,and the differences of the above indicators were significant(t=7.657,15.567,10.354,12.466,P<0.05).The scores of the standard degrees of use and operation,disinfection and sterilization,operation and maintenance,and repairing fault of equipment in the dynamic management mode group were higher than those in the conventional management mode group,and the differences of the above data between two groups were statistically significant(t=16.289,11.415,13.396,9.420,P<0.05),respectively.The rate of standard placement,the rate of reasonable recording and integrity rate of equipment in the dynamic management mode group were higher than those in the conventional management mode group,and the failure rate was lower than that of the conventional management mode group,and the differences of the above indicators between the two groups were statistically significant(x2=6.708,7.070,8.491,13.333,P<0.05).Conclusion:The risk assessment and dynamic management based on HACCP system for operational safety of medical equipment in surgery room can improve the management effect for equipment in surgery room,and reduce the operational risk of equipment,and realize the whole-process management and control for medical equipment in surgery room.
8.Distribution of allergen components of dust mite in children with airway allergic diseases
Huijie HUANG ; Li XIANG ; Nannan JIANG ; Mian WEI ; Xiaoling HOU
Chinese Journal of General Practitioners 2025;24(5):581-586
Objective:To analyze the distribution of allergen components of dust mite in children with airway allergic diseases.Methods:This was a cross-sectional study. The clinical data of children with dust mite-induced allergic asthma (AA) complicated with allergic rhinitis (AR) or allergic rhinitis who were treated in Department of Allergy,Beijing Children′s Hospital from January 2019 to October 2022 were retrospectively analyzed. The spedific IgE (sIgE) levels to Der p1,Der p2,Der p5,Der p7,Der p10,Der p21,Der p23 and Der f1,Der f2 were detected by protein chip method. The distribution of dust mite sensitized components and the sIgE levels in children with different airway allergic diseases and different ages were compared.Results:Among 138 children with airway allergic diseases,there were 97 boys and 41 girls,age (6.86±2.61) years old,and there were 106 cases of AA combined AR (AAAR group) and 32 cases of AR alone (AR group). The sensitization rates of Der p2 was the highest (75.4%,104/138),followed by Der f2 (74.6%,103/138),Der f1 (73.9%,102/138),Der p1 (71.7%,99/138),Der p21 (19.6%,27/138),Der p5 (16.7%,23/138),Der p23 (14.5%,20/138),Der p7 (11.6%,16/138) and Der p10 (2.9%,4/138). The co-sensitization rate of Der p1,Der p2,Der f1 and Der f2 was the highest (31.2%,43/138). There was no significant difference in sensitization rate of dust mites components between AAAR group and AR group(all P>0.05). AAAR group had higher levels of sIgE to Der p23 than AR group [0.1 (0,0.1) IU/ml vs. 0 (0,0.1) IU/ml,Z=-2.819, P=0.005]. There were no significant differences in the positive rate of dust mite components and sIgE levels between children aged≤6 and>6 years old with airway allergic diseases(all P>0.05). Conclusions:Der p1,Der p2,Der f1 and Der f2 are the major components of dust mites sensitizing airway allergic diseases in children. Der p1,Der p2,Der f1 and Der f2 are the main co-sensitizing components in children with dust mite-induced airway allergic diseases. Compared with AR,the sIgE level to Der p23 in children with AAAR is higher.
9.Risk factors for sarcopenia in patients with Wilson’s disease-related liver cirrhosis and their impact on clinical outcomes
Weiqi WANG ; Taohua WEI ; Nannan QIAN ; Wenming YANG ; Yulong YANG ; Yuqi SONG ; Wenjie HAO ; Yue YANG ; Hu XI ; Wei HE
Journal of Clinical Hepatology 2025;41(10):2075-2081
ObjectiveTo investigate the incidence rate of sarcopenia in patients with Wilson’s disease (WD)-related liver cirrhosis, as well as the risk factors for sarcopenia and their impact on clinical outcomes. MethodsA total of 140 patients with WD-related liver cirrhosis who were treated in The First Affiliated Hospital of Anhui University of Chinese Medicine from January 2019 to June 2020, and according to the third lumbar skeletal muscle mass index (L3 SMI), the patients were divided into sarcopenia group and non-sarcopenia group. Nutritional risk screening, anthropometric measurements, and blood biochemical tests were performed for the patients to identify the influencing factors for sarcopenia. The patients were followed up for 36 — 48 months, and survival status and complications were compared between the two groups. The independent-samples t test was used for comparison of normally distributed continuous data between two groups, and the chi-square test and the Mann-Whitney U rank sum test were used for comparison of categorical data between two groups. A binary Logistic regression analysis was used to investigate the influencing factors for sarcopenia, and univariate and multivariate Cox regression analyses were used to investigate the risk factors for the prognosis of patients with WD-related liver cirrhosis. The Kaplan-Meier survival curve was plotted, and the Log-rank test was used for comparison between groups. ResultsAmong the 140 patients with WD-related liver cirrhosis, 53 (37.9%) developed sarcopenia, with significantly lower body mass index (BMI) and L3 SMI than the patients without sarcopenia (t=10.550 and 3.982, both P<0.001). The multivariate Logistic regression analysis showed that age (odds ratio [OR]=2.243, 95% confidence interval [CI]: 1.196 — 4.208, P=0.012), sex (OR=0.450, 95%CI: 0.232 — 0.872, P=0.018), BMI (OR=0.126, 95%CI: 0.089 — 0.294, P<0.001), and hepatic encephalopathy (OR=8.367, 95%CI: 2.423 — 28.897, P<0.001) were the main influencing factors for sarcopenia in patients with WD-related liver cirrhosis. Compared with the non-sarcopenia group, the sarcopenia group had significantly higher mortality rate (χ2=6.158, P=0.019) and significantly higher incidence rates of infection (χ2=8.008, P=0.040), recurrent abdominal/pleural efflux (χ2=17.742, P<0.001), and hepatic encephalopathy (χ2=4.338, P=0.039). The multivariate Cox regression analysis showed that sarcopenia (hazard ratio [HR]=4.685, P=0.002) and hepatic encephalopathy (HR=19.156, P<0.001) were independent risk factors for death in patients with WD-related liver cirrhosis. The Kaplan-Meier survival curve analysis showed a significant reduction in survival rate in the patients with sarcopenia (P=0.003). ConclusionSarcopenia is one of the manifestations of malnutrition in patients with WD-related liver cirrhosis, which increases the risk of mortality and other complications and has an adverse effect on prognosis. There is an increased risk of sarcopenia in male patients or patients with hepatic encephalopathy, a lower level of BMI or an older age.
10.Construction and biological characterization of a dual sagA/aroA gene deletion mutant strain of donkey-derived Streptococcus equi subsp. equi
Bing LIU ; Guangyuan LIU ; Nannan GAO ; Zhaoliang DING ; Jie YU ; Chuanlu WEI ; Haijing LI ; Hua WANG ; Shishan DONG ; Jianbao DONG
Chinese Journal of Veterinary Science 2025;45(11):2365-2371
Strangles,caused by Streptococcus equi subsp.equi,remains one of the most prevalent and high-incidence infectious diseases in intensive donkey farms,posing a significant threat to the healthy development of the donkey industry.Vaccination serves as an effective measure for the pre-vention and control of the disease,however,there is currently no attenuated vaccine against this disease in China.To provide a candidate strain for the development of a live attenuated strangles vaccine,this study focused on a wild-type S.equi subsp.equi strain isolated from donkeys.Using homologous recombination gene knockout technology,the aroA gene(encoding 5-enolpyru-vylshikimate-3-phosphate synthase)and the sag A gene(encoding the precursor of streptolysin S toxin)were sequentially deleted to construct a double-gene-deletion strain(ΔsagA/aroA).The virulence and key biological characteristics of the mutant strain were systematically evaluated.TheΔsagA/aroA strain was successfully generated,exhibiting complete loss of hemolytic activity and maintaining stable genetic inheritance over 60 consecutive passages.Electron microscopy revealed that the mutant retained morphological characteristics compared to the wild-type strain,and its growth rate was significantly slower(P<0.000 1).Virulence assessment using a challenge dose of 1× 105 CFU/0.2 mL(the minimum fully lethal dose of the wild-type strain)demonstrated markedly attenuated virulence in the mutant.Immunization trials with 1 ×104 CFU/0.2 mL of theΔsagA/aroA strain revealed a increase in ELISA antibody titers by day 7 post-vaccination,and higher levels at days 14 and 21.Notably,antibody levels in the experimental group were significant-ly higher than those in the control group(P<0.000 1).These findings confirm that the double-gene-deletion strain S.equi subsp.equi ΔsagA/aroA exhibits reduced virulence while retaining im-munogenicity,which suggested it can be used as a promising candidate strain for further develop-ment of a live attenuated strangles vaccine.

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