1.Progress in depression research using genetically modified animal models
Mengyao LI ; Feng GAO ; Fanfan ZHENG ; Mengze HE ; Zhao HE ; Youlei LI
Acta Laboratorium Animalis Scientia Sinica 2023;31(12):1610-1616
Depression is a complex mental disease with polygenic inheritance and a high incidence.Our understanding of the clinical manifestations and pathogenesis of depression has recently improved.Continuous progress in gene-editing technologies has increased the construction efficiency and reduced the cost of gene-knockout animals,leading to their increasing use in the fields of basic research and drug development for depression and providing a powerful tool for revealing the pathogenesis of depression.In this review,we summarize recent progress in understanding the roles and mechanisms of candidate genes in depression using knockout model mice.
2.Research progress on the correlation between cirrhosis and frailty
Yafang ZHAO ; Mengyao ZHENG ; Huiling ZHU ; Jinhui YANG
Chinese Journal of Hepatology 2023;31(8):891-896
Frailty, which predicts high dependency and mortality, is a major challenge for healthcare systems in nations that are rapidly aging and is receiving increasing attention. Cirrhosis is often combined with frailty, which has a significant impact on patient health outcomes. Understanding the risk factors for frailty, elucidating the mechanism of cirrhosis combined with frailty, and early recognition and slowing down the occurrence and development of frailty are of great significance for the prognosis of cirrhotic patients. This article reviews the current research status of cirrhosis combined with frailty, including the definition and risk factors, mechanism, correlation, and intervention measures, in order to improve understanding and provide assistance for strengthening early identification, management, and intervention.
3.Effects of stress-induced protein Sestrin2 on necroptosis of dendritic cells induced by lipopolysaccharide
Mengyao WU ; Renqi YAO ; Yu DUAN ; Lu WANG ; Liyu ZHENG ; Pengyi HE ; Ning DONG ; Yao WU ; Yongming YAO
Chinese Critical Care Medicine 2024;36(3):237-243
Objective:To investigate the effect of stress-induced protein Sestrin2 (SESN2) on necroptosis of mouse dendritic cell (DC) induced by lipopolysaccharide (LPS) combined with zVAD, a panaspartate-specific cysteine protease (caspase) inhibitor.Methods:The DC2.4 cell line derived from the bone marrow of mouse in the 3rd to 10th generations was cultured. The cells were stimulated with LPS for 0 hour, 6 hours, 12 hours, and 24 hours, and grouped according to the stimulation time points. Western blotting was performed to determine the protein expression of SESN2 in each group. Overexpression empty lentivirus (NC), SESN2 gene overexpression RNA sequence lentivirus (SESN2 LV-RNA), small interfering empty lentivirus (NS), and SESN2 gene small interfering RNA sequence lentivirus (SESN2 siRNA) were transfected into DC2.4 cells. After 72 hours of transfection, cell fluorescence expression was observed under the inverted fluorescence microscope. Cells in each transfection group were stimulated with LPS for 24 hours. The blank control groups were set up and cultured with phosphate buffered saline (PBS) for 24 hours. Western blotting was performed to measure SESN2 protein expression. In the same groups as above, cells were stimulated with LPS+zVAD for 24 hours. The blank control groups were set up and cultured with PBS for 24 hours. Western blotting was used to determine the expression of mixed lineage kinase domain-like protein (MLKL) and phosphorylated-MLKL (p-MLKL). The p-MLKL levels and the number of positive cells were observed using laser scanning confocal microscopy. The necroptotic cell ratios were assessed by both flow cytometry and Hoechst staining.Results:Compared to the LPS 0 hour group, the expression of SESN2 in the LPS 24 hours group showed a significant increase. Therefore, 24 hours was chosen as the subsequent stimulation time point. After successful lentivirus transduction and 24 hours of cultivation, the MLKL phosphorylation level in the SESN2 siRNA+LPS+zVAD group was significantly higher than that in the NS+LPS+zVAD group. The MLKL phosphorylation in the SESN2 LV-RNA+LPS+zVAD group was significantly lower than that in the NC+LPS+zVAD group. The MLKL phosphorylation levels in both the NS+LPS+zVAD group and the NC+LPS+zVAD group were obviously higher than those in the NS+PBS group and the NC+PBS group, respectively. Laser scanning confocal microscopy showed that the trends in quantity and fluorescence intensity of p-MLKL protein expressions were consistent with the above results. The results from flow cytometry analysis and Hoechst staining showed that the rates of cell necrotic apoptosis in SESN2 siRNA+LPS+zVAD group were significantly higher than those in NS+LPS+zVAD group [flow cytometry analysis: (30.800±1.153)% vs. (20.800±1.114)%, Hoechst staining: (75.267±0.451)% vs. (46.267±3.371)%, both P < 0.05], indicating that knocking down SESN2 further exacerbated the occurrence of necroptosis. The necrotic apoptosis rates in SESN2 LV-RNA+LPS+zVAD group were significantly lower than those in NC+LPS+zVAD group [flow cytometry analysis: (7.160±0.669)% vs. (19.240±2.322)%, Hoechst staining: (32.433±3.113)% vs. (48.567±4.128)%, both P < 0.05], indicating that overexpressing SESN2 reversed such response and markedly reduced the proportion of necroptotic cells compared to the corresponding empty vector group. Conclusion:SESN2 exhibits an inhibitory effect on necroptosis of DC in sepsis. Targeted SESN2 expression may regulate the process of DC-mediated immune response in sepsis.
4.Association of metabolic associated fatty liver disease with carotid atherosclerotic plaque and stenosis
Yingdie ZHU ; Zhijiao ZHANG ; Guilin ZHANG ; Yunkun GAO ; Mengyao ZHENG ; Hua HUANG ; Gongfang ZHAO
Journal of Clinical Hepatology 2024;40(8):1591-1597
Objective To investigate the association between metabolic associated fatty liver disease(MAFLD)and carotid atherosclerotic plaque.Methods A total of 1 107 patients who were hospitalized in The Second Affiliated Hospital of Kunming Medical University from July,2014 to December,2022 were enrolled,and all patients underwent abdominal ultrasound and CT angiography of the head and neck arteries.Baseline data and clinical diagnosis were collected,and the patients were divided into MAFLD group with 499 patients and non-MAFLD group with 608 patients based on medical history,clinical tests,and imaging findings.According to the CT value,carotid plaques were classified into calcified plaques,non-calcified plaques,and mixed plaques.According to the NASCET criteria,carotid stenosis was categorized as normal vessel,slight stenosis,mild stenosis,moderate stenosis,and severe stenosis/occlusion.The independent-samples t test was used for comparison of normally distributed continuous data between two groups,and the Mann-Whitney U rank sum test was used for comparison of non-normally distributed continuous data between two groups;the chi-square test was used for comparison of categorical data between two groups.Univariate and multivariate Logistic regression analyses were used to investigate the influencing factors for carotid atherosclerosis.Results Compared with the non-MAFLD group,the MAFLD group had a significantly higher proportion of patients with calcified plaques(74.3%vs 63.3%,P<0.05),non-calcified plaques(27.1%vs 17.1%,P<0.05),or mixed plaques(27.3%vs 20.7%,P<0.05),as well as a significantly higher proportion of patients with mild stenosis(50.9%vs 44.9%,P<0.05),moderate stenosis(14.6%vs 8.4%,P<0.05),or severe stenosis/occlusion(6.6%vs 3.5%,P<0.05).The univariate logistic regression analysis showed that MAFLD was a risk factor for calcified carotid plaques,non-calcified plaques,and mixed plaques,and it was also a risk factor for mild stenosis,moderate stenosis,and severe stenosis/occlusion of the carotid artery(all P<0.05).After adjustment for confounding factors,the multivariate Logistic regression analysis showed that MAFLD was an independent risk factor for calcified plaque,non-calcified plaque,mixed plaque,and moderate stenosis of the carotid arteries(all P<0.05).Conclusion MAFLD is an independent risk factor for moderate stenosis,calcified plaques,non-calcified plaques,and mixed plaques of the carotid arteries.
5.Regulatory role of circIGF2BP3 in autophagy in photoaged dermal fibroblasts
Yingying QU ; Jiaqi FANG ; Mengting OUYANG ; Mengyao WANG ; Xianyin HUANG ; Yue ZHENG ; Wei LAI ; Qingfang XU
Chinese Journal of Dermatology 2022;55(1):40-46
Objective:To preliminarily investigate the effect of circIGF2BP3 on autophagy in photoaged dermal fibroblasts.Methods:Human dermal fibroblasts were isolated from circumcised foreskin tissues from 6 children in the Department of Urological Surgery, Third Affiliated Hospital of Sun Yat-sen University. An ultraviolet A (UVA) -induced photoaged human dermal fibroblast model (UVA radiation group) was established by repeated UVA radiation at a dose of 10 J/cm 2 for 14 consecutive days, and human dermal fibroblasts receiving no treatment served as control group. The photoaged cell model was verified by β-galactosidase staining, Western blot analysis for determining P21 protein expression, and cell counting kit-8 (CCK8) assay for evaluating cell viability. Moreover, Western blot analysis was performed to determine the protein expression of autophagy-related proteins P62, microtubule-associated protein 1 light chain 3 (LC3) -Ⅰand LC3-Ⅱ in photoaged human dermal fibroblasts, and real-time quantitative RCR (qRT-PCR) to verify the differential expression of circIGF2BP3 between photoaged and normal human dermal fibroblasts. Furthermore, circIGF2BP3 was biologically annotated. Some cultured primary human dermal fibroblasts were divided into 4 groups: empty vector group transfected with an empty vector, UVA + empty vector group transfected with an empty vector followed by repeated UVA radiation, circIGF2BP3 group transfected with a circIGF2BP3-overexpressing lentiviral vector, UVA + circIGF2BP3 group transfected with a circIGF2BP3-overexpressing lentiviral vector followed by repeated UVA radiation. Western blot analysis was performed to determine the expression of autophagy-related proteins. Statistical analysis was carried out by using t test, one-way analysis of variance and least significant difference- t test. Results:Compared with the control group, the UVA radiation group showed significantly increased proportions of β-galactosidase-positive cells (61.33% ± 5.78% vs. 6.37% ± 0.32%, t = 9.49, P < 0.01) and P21 expression (1.25 ± 0.03 vs. 1.00 ± 0.05, t = 4.26, P < 0.05), but significantly decreased cell viability (74.33% ± 3.48% vs. 100%, t = 7.38, P < 0.01). Moreover, the P62 expression and LC3-Ⅱ/Ⅰ ratio were significantly higher in the UVA radiation group than in the control group (both P < 0.05). The relative expression of circIGF2BP3 was 0.72 ± 0.04 in the photoaged human dermal fibroblasts, which was significantly lower than that in the normal human dermal fibroblasts (1.00 ± 0.03, t = 5.46, P < 0.01). The P62 expression and LC3-Ⅱ/Ⅰ ratio were significantly lower in the circIGF2BP3 group (0.60 ± 0.01, 0.71 ± 0.01, respectively) than in the empty vector group (1.00 ± 0.02, 1.00 ± 0.01, t = 16.25, 2.75, P < 0.01, < 0.05, respectively), and lower in the UVA + circIGF2BP3 group (1.05 ± 0.02, 2.04 ± 0.05, respectively) than in the UVA + empty vector group (1.31 ± 0.02, 2.72 ± 0.14, t = 10.493, 6.472, respectively, both P < 0.01) . Conclusion:circIGF2BP3 can regulate autophagy in UVA-induced photoaged dermal fibroblasts, which provides a new potential therapeutic target for the prevention and treatment of skin photoaging.
6.The effect of glycopyrrolate on intestinal spasm and hemodynamics in painless colonoscopy
Yan ZHANG ; Mengyao YI ; Changfeng FANG ; Le ZHANG ; Jie ZHENG ; Yuanxiao LU ; Qi YE ; Zhijian YE ; Tao FANG
Chinese Journal of Internal Medicine 2024;63(6):600-604
Objective:To investigate the effects of glycopyrrolate on intestinal spasm and hemodynamics in painless colonoscopy.Methods:A total of 100 patients who were scheduled to undergo painless colonoscopy were selected as the study subjects and randomly divided into two groups by a computerized number method. Ten patients in both groups dropped out because of disruption of the study protocol, and 45 patients from each group were included in the final analysis. Before anesthesia induction, patients in group glycopyrrolate (group G) were injected with 0.2 mg glycopyrrolate, while those in congtrol group (group C) were injected with an equal amount of saline. The heart rate, systolic blood pressure, and diastolic blood pressure were recorded at T 0 (baseline period), T 1 (after anesthesia induction), T 2 (colonoscopy over sigmoid colon), T 3 (colonoscopy over the liver region), T 4 (after the end of examination), and T 5 (at the awakening phase), and the degree of intestinal spasm was assessed intraoperatively using the Likert′s four-point scale. The numerical rating scale (NRS) was used to assess preoperative and postoperative pain. The incidence of adverse events was recorded. Results:The general data at baseline were not statistically different between the two groups ( P>0.05). During the procedure, patients in group G had lower intraoperative intestinal spasm scores than those in group C ( P=0.028). Intraoperative hypotension and bradycardia occurrence were lower in group G than in group C ( P<0.05), and intraoperative norepinephrine use was also lower than in the group C ( P=0.034). Postoperative visual analog scale pain scores were lower in group G ( P=0.047), but patients who used glycopyrrolate had a higher proportion of dry mouth ( P=0.035). Conclusion:During painless colonoscopy, preoperative administration of glycopyrrolate significantly improved intraoperative hemodynamic fluctuations, reduced the incidence of hypotension and bradycardia, and relieved postoperative pain. However, glycopyrrolate use resulted in the risk of dry mouth.
7.Effects of stimulator of interferon gene on ferroptosis mediated by acyl-CoA synthetase long-chain family member 4 in mouse dendritic cells under sepsis
Mengyao WU ; Pengyi HE ; Yu DUAN ; Liyu ZHENG ; Renqi YAO ; Qiyuan ZHOU ; Yu CHEN ; Ning DONG ; Yao WU ; Yongming YAO
Chinese Journal of Burns 2024;40(10):920-929
Objective:To investigate the effects of stimulator of interferon gene (STING) on ferroptosis mediated by acyl-CoA synthetase long-chain family member 4 (ACSL4) in mouse dendritic cells (DCs) under sepsis, providing a basis for improving the dysregulation of immune response in sepsis caused by factors such as wound infection.Methods:This study was an experimental research. The mouse DC line DC2.4 in the logarithmic growth phase (with passages 3-10) were divided into lipopolysaccharide (LPS) stimulation 0 h (unstimulated) group, LPS stimulation 6 h group, LPS stimulation 12 h group, LPS stimulation 18 h group, and LPS stimulation 24 h group according to the random number table (the same grouping method below), which were cultured with 1 μg/mL LPS (the same concentration below) for the corresponding time. The protein expressions of phosphorylated STING (p-STING), STING, and ACSL4 in cells were determined by Western blotting. DC2.4 successfully transfected with lentivirus containing STING gene small interfering RNA (hereinafter referred to as siSTING) were divided into siSTING+phosphate buffer solution (PBS) group and siSTING+LPS group. DC2.4 successfully transfected with empty lentivirus were divided into empty vector+PBS group and empty vector+LPS group. After being stimulated with PBS or LPS and cultured for 24 hours, the protein expressions of p-STING, STING, and ACSL4 in cells were determined as above. Cell lipid peroxidation degrees were observed using the lipid peroxidation assay kit, and cell apoptosis rates were detected using flow cytometry. The sample numbers in the above cell experiments were all 3. Eighty male C57BL/6J mice aged 6 to 8 weeks were divided into sham surgery+normal saline (NS) group, cecal ligation and puncture (CLP)+NS group, sham surgery+C-176 group, and CLP+C-176 group, with 20 mice in each group. Mice in the two C-176 groups were intraperitoneally injected with C-176, while mice in the two NS groups were intraperitoneally injected with an equivalent volume of NS. One hour later, sham surgery was performed on the mice in the two sham surgery groups, and CLP surgery was performed on the mice in the two CLP groups to establish a sepsis model. At 24 h post-surgery, 10 mice from each group were sacrificed to extract spleen DCs, and protein expression, lipid peroxidation, and apoptosis rates were detected as above ( n=3). Hematoxylin-eosin staining was performed to observe pathological damage in the heart, liver, lung, and kidney tissue. The remaining 10 mice in each group were observed for survival within 7 days after surgery. Results:The protein expressions of p-STING, STING, and ACSL4, as well as the p-STING/STING ratio in DC2.4 in LPS stimulation 24 h group were significantly higher than those in LPS stimulation 0 h group ( P<0.05). After 24 h of culture, the protein expressions of p-STING, STING, and ACSL4 in DC2.4 in siSTING+LPS group and empty vector+PBS group were significantly lower than those in empty vector+LPS group ( P<0.05); the lipid peroxidation degrees of DC2.4 in siSTING+LPS group and empty vector+PBS group were weaker than those in empty vector+LPS group. The apoptosis rates of DC2.4 in empty vector+PBS group, empty vector+LPS group, siSTING+PBS group, and siSTING+LPS group were (15.7±3.0)%, (37.8±2.9)%, (13.1±2.1)%, and (20.6±1.8)%, respectively. The apoptosis rates of DC2.4 in empty vector+PBS group and siSTING+LPS group were significantly lower than that in empty vector+LPS group ( P<0.05). At 24 h post-surgery, the protein expressions of p-STING and ACSL4, and the p-STING/STING ratio in spleen DCs of mice in CLP+NS group were significantly higher than those in sham surgery+NS group and CLP+C-176 group ( P<0.05); the protein expression of STING in spleen DCs of mice in CLP+NS group was significantly higher than that in sham surgery+NS group ( P<0.05); the lipid peroxidation degrees of spleen DCs of mice in CLP+C-176 group and sham surgery+NS group were weaker than that in CLP+NS group. The apoptosis rates of spleen DCs of mice in sham surgery+NS group and CLP+C-176 group were significantly lower than that in CLP+NS group ( P<0.05), and the apoptosis rate of spleen DCs of mice in CLP+C-176 group was significantly higher than that in sham surgery+C-176 group ( P<0.05). Pathological tissue damage in the heart, liver, lung, and kidney of mice in CLP+NS group was significantly worse than that in sham surgery+NS group, while such damage in the above organs of mice in CLP+C-176 group was significantly alleviated compared with that in CLP+NS group. The survival ratio of mice in CLP+NS group within 7 days after surgery was significantly lower than that in sham surgery+NS group ( χ2=8.30, P<0.05). Conclusions:Under sepsis, STING activation in mouse DCs is significant, which enhances ACSL4-mediated ferroptosis. Inhibiting STING activation can significantly reduce ACSL4-mediated ferroptosis level in mouse DCs under sepsis, thereby improving the survival rate of septic mice.
8.Effect of Yiguan Decoction on the efficacy of M1 bone marrow-derived macrophages in treatment of liver cirrhosis rats and its mechanism
Mengyao ZONG ; Xun JIAN ; Danyang WANG ; Yannan XU ; Xinrui ZHENG ; Feifei XING ; Gaofeng CHEN ; Jiamei CHEN ; Ping LIU ; Yongping MU
Journal of Clinical Hepatology 2024;40(8):1612-1619
Objective To investigate the effect and mechanism of Yiguan Decoction(YGJD)on the efficacy of M1 bone marrow-derived macrophages(M1-BMDMs)in the treatment of rats with liver cirrhosis induced by 2-AAF/CCl4.Methods BMDMs were isolated and induced into M1-BMDMs by lipopolysaccharide.A total of 50 male Wistar rats were randomly divided into normal group with 5 rats and model group with 45 rats.The rats for modeling were given subcutaneous injection of 50%CCl4 twice a week.Since week 7,the rats for modeling were randomly divided into model group(M group),YGJD group,M1-BMDM group,M1-BMDM+YGJD group,and sorafenib(SORA)group,and they were given subcutaneous injection of 30%CCl4 to maintain the progression of liver cirrhosis and intragastric administration of 2-AAF.CCR2 inhibitors were added to the drinking water,and each group was given the corresponding intervention.Related samples were collected at week 9.The rats were observed in terms of serum liver function parameters,liver pathology,hydroxyproline(Hyp)content in liver tissue,hepatic stellate cell activation,hepatic fibrosis and inflammation factors,and the expression levels of molecules associated with the Wnt signaling pathway.A one-way analysis of variance was used for comparison of continuous data between multiple groups,and the least significant difference t-test was used for further comparison between two groups.Results Compared with the M group,the M1-BMDM+YGJD group had significant reductions in the serum levels of alanine aminotransferase,aspartate aminotransferase,and total bilirubin(TBil)(all P<0.05)and a significant increase in the content of albumin(Alb)(P<0.05),and compared with the M1-BMDM group,the M1-BMDM+YGJD group had a significant reduction in the serum level of TBil(P<0.05)and a significant increase in the serum level of Alb(P<0.05).Compared with the M1-BMDM group,the M1-BMDM+YGJD group had significant reductions in the expression levels of CD68 and TNF-α(P<0.05).Compared with the M1-BMDM group,the M1-BMDM+YGJD group had significant reductions in Hyp content and Sirius red positive area(P<0.05).As for the non-canonical Wnt signaling pathway molecules,compared with the M1-BMDM group,the M1-BMDM+YGJD group had significantly lower mRNA and protein expression levels of Wnt5a(P<0.05)and mRNA expression level of Fzd2(P<0.05),as well as significant reductions in the mRNA expression levels of Wnt4,Wnt5b,and Fzd3(P<0.05),while there were no significant changes in the mRNA expression levels of the canonical Wnt signaling pathway molecules β-catenin,LRP5,LRP6,Fzd5,and TCF.Conclusion YGJD can enhance the therapeutic effect of M1-BMDMs on rats with liver cirrhosis induced by 2-AAF/CCl4,possibly by inhibiting the non-canonical Wnt5a/Fzd2 signaling pathway,which provides new ideas for the synergistic effect of traditional Chinese medicine on M1-BMDMs in the treatment of liver cirrhosis.
9.The influence of diagnostic criteria of different guidelines on short-term prognosis of artificial liver therapy for acute-on-chronic liver failure
Yuhang CHEN ; Zimeng JIANG ; Zhijiao ZHANG ; Mengyao ZHENG ; Meilian WANG ; Hua HUANG ; Gongfang ZHAO
Journal of Clinical Hepatology 2023;39(11):2629-2634
ObjectiveTo investigate the influence of different diagnostic criteria on the short-term prognosis of patients with acute-on-chronic liver failure (ACLF). MethodsA total of 115 ACLF patients who were hospitalized in Department of Gastroenterology, The Second Affiliated Hospital of Kunming Medical University, from January 2018 to January 2022 were enrolled, and all patients received internal medical treatment combined with artificial liver therapy. According to the guidelines, the patients were divided into CMA guideline group (Diagnostic and treatment guidelines for liver failure by Chinese Medical Association)(n=100), APASL guideline group (Consensus statements of Asian Pacific Association for the Study of the Liver)(n=94), and EASL guideline group (Criteria proposed by European Association for the Study of the Liver)(n=36). The above three guidelines were compared in terms of 90-day mortality rate. A one-way analysis of variance was used for comprision of continuous date between groups; the chi-square test was used for comprision of categorical date between groups. The receiver operating characteristic (ROC) curve of related variables. ResultsThe 90-day mortality rate was 50.0% in the CMA guideline group, 51.1% in the APASL guideline group, and 77.8% in the EASL guideline group, and the EASL guideline group had a significantly higher 90-day mortality rate than the CMA guideline group (χ2=8.351, P=0.004) and the APASL guideline group (χ2=7.650, P=0.006). EASL guideline had a sensitivity of 22.2% and a specificity of 92.3% in predicting the risk of short-term mortality, with an area under the ROC curve was 0.576. ConclusionACLF patients who meet EASL guideline tend to have a worse short-term prognosis, and this guideline may help to identify patients at a relatively high risk of short-term death.
10.Muscle Force Characteristics of Knee Joints in Taekwondo Roundhouse Kick
Mengyao JIA ; Yong MA ; Jun XIONG ; Lin LIU ; Qian PENG ; Shijie LIN ; Weitao ZHENG
Journal of Medical Biomechanics 2024;39(5):969-977
Objective To explore the muscle force characteristics of the knee joint during a Taekwondo roundhouse kick in Korea.Methods Kinematic and dynamic data from twelve elite Taekwondo athletes were collected using the DaeDo electronic scoring system,Vicon optical motion capture system,Kistler three-dimensional force plates.The OpenSim software was used to simulate these movements and calculate the muscle forces,joint torques,joint stiffness,and muscle coordination patterns of the knee.Results During the knee-lifting and striking phases,the coronal torque of the knee joint in the attacking leg was significant,and the sagittal torque peaked during the strike.For the supporting leg,the highest coronal torque of the knee joint occurred during knee lifting,with the sagittal torque reaching its peak during strike.In terms of muscle activity,the semimembranosus and long head of the biceps femoris in the attacking leg exerted greater force during the striking phase,whereas the semimembranosus and medial head of the gastrocnemius in the supporting leg were more active during the recovery phase.Five muscle synergy patterns were observed during the Taekwondo roundhouse kick.Conclusions Significant differences were found in the muscle forces and knee joint torques of the attacking and supporting legs when athletes performed the roundhouse kick,and there was a complex muscle synergy.