ObjectiveTo investigate the mechanism of Zuogui Wan （ZGW） in improving ovarian inflammatory microenvironment and stemness of ovarian germline stem cells （OSCs） for treating ovarian aging via the cyclic guanosine monophosphate/adenosine monophosphate synthase （cGAS）/stimulator of interferon genes （STING） signaling pathway. MethodsForty C57BL/6 female mice were randomly divided into a blank group， a model group， a low-dose ZGW group （2.7 g·kg^-1）， a high-dose ZGW group （5.4 g·kg^-1）， and an estradiol valerate group （0.15 mg·kg^-1）， with 8 mice in each group. Except the blank group， all other groups received a single intraperitoneal injection of cyclophosphamide at 120 mg·kg^-1 to establish an ovarian aging mouse model. After successful modeling， each group was continuously administered for 4 weeks， once daily. The physiological status of the mice was observed， and the ovarian index was calculated. The estrus cycle of the mice was monitored. Hematoxylin-eosin （HE） staining was used to observe pathological changes in ovarian tissue. Enzyme-linked immunosorbent assay （ELISA） was used to detect serum sex hormone levels. Serum inflammatory factors interleukin-1β （IL-1β）， tumor necrosis factor-α （TNF-α）， and mouse interleukin-6 （IL-6） levels were detected using kits. Western blot was used to detect the protein expression of ovarian cGAS， STING， p-STING， TANK-binding kinase 1 （TBK1）， p-TBK1， interferon-induced transmembrane protein 3 （Fragilis）， and Vasa homolog protein （MVH）. Quantitative real-time polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of inflammatory factors in ovarian tissue. Immunofluorescence double labeling was performed to locate OSCs in ovarian tissues， and fluorescence intensities of OSCs markers MVH and octamer binding transcription factor 4 （Oct4） were calculated. ResultsCompared with the blank group， the model group showed reduced body weight， ovarian wet weight， and ovarian index （P<0.01） and a disordered estrus cycle （P<0.01）. In addition， the levels of serum follicle-stimulating hormone （FSH）， TNF-α， IL-6， and IL-1β were increased （P<0.01）， while anti-Müllerian hormone （AMH） and estradiol （E₂） levels were decreased （P<0.01）. The protein expression of cGAS， p-STING/STING， and p-TBK1/TBK1 in ovarian tissue was increased （P<0.05， P<0.01）， while that of OSCs stemness factors MVH and Fragilis was reduced （P<0.01）. Immunofluorescence indicated a reduction in MVH and Oct4 expression in OSCs （P<0.01）. The mRNA expression of inflammatory factors TNF-α， IL-6， and IL-1β in ovarian tissue was increased （P<0.05， P<0.01）. Compared with the model group， the treatment groups exhibited improved body weight， ovarian wet weight， and ovarian index （P<0.05） and a reduced rate of estrus cycle disorder （P<0.05， P<0.01）. The levels of serum FSH， TNF-α， IL-6， and IL-1β were decreased （P<0.05， P<0.01）， while AMH and E₂ levels were increased （P<0.01）. The protein expression levels of cGAS， p-STING/STING， and p-TBK1/TBK1 in ovarian tissue were decreased （P<0.05）， while the protein expression of MVH and Fragilis was increased （P<0.05）， and the fluorescence intensities of MVH and Oct4 were increased （P<0.05， P<0.01）. The mRNA expression of inflammatory factors in ovarian tissue was decreased （P<0.05）. ConclusionZGW alleviate ovarian inflammatory response， regulate ovarian microenvironment homeostasis， and maintain stemness of OSCs in ovarian aging mice probably by modulating the cGAS-STING signaling pathway， thereby improving ovarian function and delaying ovarian aging.

Objective:To investigate the incidence of shoulder work-related musculoskeletal disorders (WMSDs) among occupational population in China, and to explore their intrinsic association with personal and work-related factors.Methods:In April 2024, 73497 valid questionnaires of the Chinese version of the Musculoskeletal Disorders Electronic Questionnaire were retrospectively analyzed from June 2018 to December 2023 in 22 provinces and 29 key industries in China, and the general information, occurrence of WMSDs and related risk factors of key occupational populations in different regions in China were collected. By using Chi-square test and confirmatory factor analysis, the relationship between shoulder fatigue and pain in key occupational groups and individual factors, work type, work posture and work organization was discussed, and the internal relationship was analyzed based on structural equation model.Results:Higher incidence of shoulder fatigue and pain were associated with female, lack of physical exercise, uncomfortable working posture and neck leaning forward ( P<0.05). Structural equation model analysis showed that work type, work posture and work organization were strongly correlated ( r=0.58, 0.55). Work organization and work type were strongly correlated with shoulder fatigue ( r=0.65) and moderately correlated with shoulder fatigue ( r=0.21). Shoulder fatigue was moderately associated with shoulder pain ( r=0.40). Individual factors, work type, work posture and shoulder fatigue could directly affect shoulder pain ( OR=0.07, -0.09, 0.17 and 0.40), and work type and work posture could also indirectly affect shoulder pain through shoulder fatigue ( OR=0.08, 0.03). Work organization only indirectly affected shoulder pain through shoulder fatigue ( OR=0.26) . Conclusion:The main influencing factor of shoulder pain is shoulder fatigue, followed by work posture and individual factors. Structural equation model can better reflect the complex relationship between work type, work posture and work organization and shoulder WMSDs. Improving work posture and work organization may be an effective way to control the influence of shoulder fatigue on shoulder pain.

Objective:To explore the structural equation model to explore the levels of work-related musculoskeletal disorders (WMSDs) and various risk factors in the feet and ankle of China's occupational population, providing scientific basis for for preventing WMSDs in feet and ankles.Methods:Data of 73497 national occupational epidemiological cases were selected from June 2018 to December 2023 used the Chinese version of the Electronic Questionnaire on Musculoskeletal Disorders. The adverse ergonomic factors and their source classification standard and confirmatory factor analysis were used to investigate foot and ankle WMSDs and their related risk factors (including individual factors, work organization, work posture, work type, fatigue, etc.) in key occupational groups in China, and structural equation model hypothesis, fitting, verification, and path and intermediary effect analysis were carried out. The model fit evaluation indexes included Chi-square specific degrees of freedom ( χ2/ df), gauge fit index (NFI), Tucker Lewis index (TLI), goodness of Fit index (GFI), adjusted Goodness of Fit index (AGFI) and approximate root mean square error (RMSEA) . Results:A total of 73497 occupational workers were surveyed, with local muscle fatigue and WMSDs incidence rates in the feet and ankles being 17.17% and 12.06%, respectively. The fitting index of the adjusted structural equation model basically meets the standard (GFI=1, AGFI=1, RMESA=0.042, NFI=0.716, TLI=0.663). The top three factors affecting feet and ankle WMSDs are feet and ankle muscle fatigue, work type, and work organization, with standardized path coefficients of 0.221, 0.105, and 0.095, respectively. The top two factors affecting feet and ankle muscle fatigue are work organization and work type, with standardized path coefficients of 0.548 and 0.383, respectively. Feet and ankle muscle fatigue, work type, work organization, and work posture have a direct effect on feet and ankle WMSDs, with effect values of 0.221, 0.105, 0.095, and 0.077, respectively. The organization and type of work can also have indirect effects through feet and ankle muscle fatigue, with effect values of 0.121 and 0.084, respectively.Conclusion:Feet and ankle muscle fatigue has a direct impact on WMSDs, and plays a mediating role between ankle and ankle WMSDs caused by work organization and work type. Feet and ankle muscle fatigue is an important pathway leading to feet and ankle WMSDs. It is recommended that employers and managers detect job fatigue early and take corresponding prevention and intervention measures, which can play a key role in preventing feet and ankle WMSDs.

Objective:To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases.Methods:The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established.Results:The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture ( r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture ( r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion:When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.

OBJECTIVE: To evaluate the efficacy and safety of Shexiang Tongxin Dropping Pill (STDP) in treating stable angina patients with phlegm-heat and blood-stasis syndrome by exercise duration and metabolic equivalents. METHODS: This multicenter, randomized, double-blind, placebo-controlled clinical trial enrolled stable angina patients with phlegm-heat and blood-stasis syndrome from 22 hospitals. They were randomized 1:1 to STDP (35 mg/pill, 6 pills per day) or placebo for 56 days. The primary outcome was the exercise duration and metabolic equivalents (METs) assessed by the standard Bruce exercise treadmill test after 56 days of treatment. The secondary outcomes included the total angina symptom score, Chinese medicine (CM) symptom scores, Seattle Angina Questionnaire (SAQ) scores, changes in ST-T on electrocardiogram and adverse events (AEs). RESULTS: This trial enrolled 309 patients, including 155 and 154 in the STDP and placebo groups, respectively. STDP significantly prolonged exercise duration with an increase of 51.0 s, compared to a decrease of 12.0 s with placebo (change rate: -11.1% vs. 3.2%, P<0.01). The increase in METs was significantly greater in the STDP group than in the placebo group (change: -0.4 vs. 0.0, change rate: -5.0% vs. 0.0%, P<0.01). The improvement of total angina symptom scores (25.0% vs. 0.0%), CM symptom scores (38.7% vs. 11.8%), reduction of nitroglycerin consumption (100.0% vs. 11.3%), and all domains of SAQ, were significantly greater with STDP than placebo (all P<0.01). The changes in Q-T intervals at 28 and 56 days from baseline were similar between the two groups (both P>0.05). Twenty-five participants (16.3%) with STDP and 16 (10.5%) with placebo experienced AEs (P=0.131), with no serious AEs observed. CONCLUSION STDP could improve exercise tolerance in patients with stable angina and phlegm-heat and blood stasis syndrome, with a favorable safety profile. (Registration No. ChiCTR-IPR-15006020).
Humans ; Double-Blind Method ; Drugs, Chinese Herbal/adverse effects* ; Male ; Female ; Middle Aged ; Angina, Stable/physiopathology* ; Aged ; Syndrome ; Treatment Outcome ; Placebos ; Tablets

Objective:To systematically compares the medial plantar venous flap (MPVF) and the lateral toe flap (LTF) reconstruction of digit-pulp defect, aiming to establish whether there exist significant differences between the 2 flaps in flap survival rate, two-point discrimination (TPD), score of Vancouver Scar Scale (VSS) and score of digit-pulp defect reconstruction evaluation.Methods:With a prospective cohort design, this study enrolled 36 patients who were admitted in Department of Hand Surgery, Longgang Eighth People's Hospital of Shenzhen for digit-pulp defects with bone or tendon exposure between January 2024 and September 2024. According to the random grouping method, participants were divided into 2 groups. The MPVF group comprised 18 patients (21 digits) of 13 males (15 digits) and 5 females (6 digits), aged 13-58 (mean 44±12) years. The MPVF group included 9 left and 12 right digits, with distribution as follows: 2 thumbs, 5 index fingers, 7 middle fingers, 5 ring fingers and 2 little fingers. The soft tissue defect area ranged from 2.0 cm × 1.0 cm to 9.2 cm × 3.3 cm (mean 6.69 cm 2± 6.69 cm 2). Flap dimensions ranged from 2.1 cm×1.1 cm to 9.5 cm×3.5 cm (mean 7.54 cm 2±7.22 cm 2). Donor sites were closed primarily or by full-thickness skin grafts harvested from the leg. The LTF group included 18 patients (21 digits) of 15 males (17 digits) and 3 females (4 digits), aged 22-62 (mean 41±12) years. The affected digits in LTF group comprised 12 left and 9 right digits, with a distribution of: 3 thumbs, 9 index fingers, 5 middle fingers, 2 ring fingers and 2 little fingers. The area of soft tissue defect ranges from 1.4 cm × 1.0 cm to 3.9 cm × 1.8 cm (mean 3.93 cm 2± 1.80 cm 2). Flap dimensions ranged from 1.5 cm×1.2 cm to 4.0 cm×1.9 cm (mean 4.52 cm 2±1.89 cm 2). Donor sites were closed primarily, or by full-thickness skin grafts harvested through extension of proximal wound extension or from calf for defect coverage. Patients were contacted for postoperative follow-up by telephone or WeChat to arrange a visit of outpatient clinic or a home visit by surgeon. Statistical analysis was conducted to compare the 2 groups regarding: gender, age and flap dimensions, flap survival rate at 2 weeks after surgery and TPD of flaps, VSS scores, and digit-pulp defect reconstruction evaluation scale scores at 4 months and 6 months postoperatively. P<0.05 indicates a statistically significant difference. Results:The comparative analysis revealed no statistically significant differences between 2 groups in baseline characteristics: gender distribution ( χ2=0.53, P=0.47), mean age ( t=0.75, P=0.46), flap dimensions ( t=1.86, P=0.08), confirming a demographic and surgical parameter equivalence in subsequent outcome comparisons ( P>0.05). All flaps survived at 2 weeks after surgery. All skin grafts at donor sites demonstrated complete viability with uneventful primary wound healing. At 4 months after surgey, the TPD in the MPVF group were 14.71 mm±1.90 mm and 7.81 mm±1.78 mm, respectively, compared to 14.48 mm±1.57 mm and 7.67 mm±1.39 mm in the LTF group at 6 months after surgery. The VSS scores were 1.67±1.11 and 1.29±0.72 for MPVF versus 1.86±1.15 and 1.38±0.81 for LTF at corresponding time points. The digit-pulp defects reconstruction evaluation scale scores showed 88.43±2.62 and 91.43±3.59 for MPVF versus 88.19±2.70 and 91.19±3.50 for LTF. Statistical analysis revealed no significant differences (all P>0.05) at 2 postoperative time points. Conclusion:The MPVF demonstrated non-inferior clinical efficacy to the LTF in reconstruction of digit-pulp defects, with comparable outcomes in flap survival rate at 2 weeks, and in TPD, VSS scores, digit-pulp defect reconstruction evaluation scale scores at 4 months and at 6 month after surgey.

Objective:To systematically compares the medial plantar venous flap (MPVF) and the lateral toe flap (LTF) reconstruction of digit-pulp defect, aiming to establish whether there exist significant differences between the 2 flaps in flap survival rate, two-point discrimination (TPD), score of Vancouver Scar Scale (VSS) and score of digit-pulp defect reconstruction evaluation.Methods:With a prospective cohort design, this study enrolled 36 patients who were admitted in Department of Hand Surgery, Longgang Eighth People's Hospital of Shenzhen for digit-pulp defects with bone or tendon exposure between January 2024 and September 2024. According to the random grouping method, participants were divided into 2 groups. The MPVF group comprised 18 patients (21 digits) of 13 males (15 digits) and 5 females (6 digits), aged 13-58 (mean 44±12) years. The MPVF group included 9 left and 12 right digits, with distribution as follows: 2 thumbs, 5 index fingers, 7 middle fingers, 5 ring fingers and 2 little fingers. The soft tissue defect area ranged from 2.0 cm × 1.0 cm to 9.2 cm × 3.3 cm (mean 6.69 cm 2± 6.69 cm 2). Flap dimensions ranged from 2.1 cm×1.1 cm to 9.5 cm×3.5 cm (mean 7.54 cm 2±7.22 cm 2). Donor sites were closed primarily or by full-thickness skin grafts harvested from the leg. The LTF group included 18 patients (21 digits) of 15 males (17 digits) and 3 females (4 digits), aged 22-62 (mean 41±12) years. The affected digits in LTF group comprised 12 left and 9 right digits, with a distribution of: 3 thumbs, 9 index fingers, 5 middle fingers, 2 ring fingers and 2 little fingers. The area of soft tissue defect ranges from 1.4 cm × 1.0 cm to 3.9 cm × 1.8 cm (mean 3.93 cm 2± 1.80 cm 2). Flap dimensions ranged from 1.5 cm×1.2 cm to 4.0 cm×1.9 cm (mean 4.52 cm 2±1.89 cm 2). Donor sites were closed primarily, or by full-thickness skin grafts harvested through extension of proximal wound extension or from calf for defect coverage. Patients were contacted for postoperative follow-up by telephone or WeChat to arrange a visit of outpatient clinic or a home visit by surgeon. Statistical analysis was conducted to compare the 2 groups regarding: gender, age and flap dimensions, flap survival rate at 2 weeks after surgery and TPD of flaps, VSS scores, and digit-pulp defect reconstruction evaluation scale scores at 4 months and 6 months postoperatively. P<0.05 indicates a statistically significant difference. Results:The comparative analysis revealed no statistically significant differences between 2 groups in baseline characteristics: gender distribution ( χ2=0.53, P=0.47), mean age ( t=0.75, P=0.46), flap dimensions ( t=1.86, P=0.08), confirming a demographic and surgical parameter equivalence in subsequent outcome comparisons ( P>0.05). All flaps survived at 2 weeks after surgery. All skin grafts at donor sites demonstrated complete viability with uneventful primary wound healing. At 4 months after surgey, the TPD in the MPVF group were 14.71 mm±1.90 mm and 7.81 mm±1.78 mm, respectively, compared to 14.48 mm±1.57 mm and 7.67 mm±1.39 mm in the LTF group at 6 months after surgery. The VSS scores were 1.67±1.11 and 1.29±0.72 for MPVF versus 1.86±1.15 and 1.38±0.81 for LTF at corresponding time points. The digit-pulp defects reconstruction evaluation scale scores showed 88.43±2.62 and 91.43±3.59 for MPVF versus 88.19±2.70 and 91.19±3.50 for LTF. Statistical analysis revealed no significant differences (all P>0.05) at 2 postoperative time points. Conclusion:The MPVF demonstrated non-inferior clinical efficacy to the LTF in reconstruction of digit-pulp defects, with comparable outcomes in flap survival rate at 2 weeks, and in TPD, VSS scores, digit-pulp defect reconstruction evaluation scale scores at 4 months and at 6 month after surgey.

Objective:To investigate the incidence of shoulder work-related musculoskeletal disorders (WMSDs) among occupational population in China, and to explore their intrinsic association with personal and work-related factors.Methods:In April 2024, 73497 valid questionnaires of the Chinese version of the Musculoskeletal Disorders Electronic Questionnaire were retrospectively analyzed from June 2018 to December 2023 in 22 provinces and 29 key industries in China, and the general information, occurrence of WMSDs and related risk factors of key occupational populations in different regions in China were collected. By using Chi-square test and confirmatory factor analysis, the relationship between shoulder fatigue and pain in key occupational groups and individual factors, work type, work posture and work organization was discussed, and the internal relationship was analyzed based on structural equation model.Results:Higher incidence of shoulder fatigue and pain were associated with female, lack of physical exercise, uncomfortable working posture and neck leaning forward ( P<0.05). Structural equation model analysis showed that work type, work posture and work organization were strongly correlated ( r=0.58, 0.55). Work organization and work type were strongly correlated with shoulder fatigue ( r=0.65) and moderately correlated with shoulder fatigue ( r=0.21). Shoulder fatigue was moderately associated with shoulder pain ( r=0.40). Individual factors, work type, work posture and shoulder fatigue could directly affect shoulder pain ( OR=0.07, -0.09, 0.17 and 0.40), and work type and work posture could also indirectly affect shoulder pain through shoulder fatigue ( OR=0.08, 0.03). Work organization only indirectly affected shoulder pain through shoulder fatigue ( OR=0.26) . Conclusion:The main influencing factor of shoulder pain is shoulder fatigue, followed by work posture and individual factors. Structural equation model can better reflect the complex relationship between work type, work posture and work organization and shoulder WMSDs. Improving work posture and work organization may be an effective way to control the influence of shoulder fatigue on shoulder pain.

Objective:To explore the structural equation model to explore the levels of work-related musculoskeletal disorders (WMSDs) and various risk factors in the feet and ankle of China's occupational population, providing scientific basis for for preventing WMSDs in feet and ankles.Methods:Data of 73497 national occupational epidemiological cases were selected from June 2018 to December 2023 used the Chinese version of the Electronic Questionnaire on Musculoskeletal Disorders. The adverse ergonomic factors and their source classification standard and confirmatory factor analysis were used to investigate foot and ankle WMSDs and their related risk factors (including individual factors, work organization, work posture, work type, fatigue, etc.) in key occupational groups in China, and structural equation model hypothesis, fitting, verification, and path and intermediary effect analysis were carried out. The model fit evaluation indexes included Chi-square specific degrees of freedom ( χ2/ df), gauge fit index (NFI), Tucker Lewis index (TLI), goodness of Fit index (GFI), adjusted Goodness of Fit index (AGFI) and approximate root mean square error (RMSEA) . Results:A total of 73497 occupational workers were surveyed, with local muscle fatigue and WMSDs incidence rates in the feet and ankles being 17.17% and 12.06%, respectively. The fitting index of the adjusted structural equation model basically meets the standard (GFI=1, AGFI=1, RMESA=0.042, NFI=0.716, TLI=0.663). The top three factors affecting feet and ankle WMSDs are feet and ankle muscle fatigue, work type, and work organization, with standardized path coefficients of 0.221, 0.105, and 0.095, respectively. The top two factors affecting feet and ankle muscle fatigue are work organization and work type, with standardized path coefficients of 0.548 and 0.383, respectively. Feet and ankle muscle fatigue, work type, work organization, and work posture have a direct effect on feet and ankle WMSDs, with effect values of 0.221, 0.105, 0.095, and 0.077, respectively. The organization and type of work can also have indirect effects through feet and ankle muscle fatigue, with effect values of 0.121 and 0.084, respectively.Conclusion:Feet and ankle muscle fatigue has a direct impact on WMSDs, and plays a mediating role between ankle and ankle WMSDs caused by work organization and work type. Feet and ankle muscle fatigue is an important pathway leading to feet and ankle WMSDs. It is recommended that employers and managers detect job fatigue early and take corresponding prevention and intervention measures, which can play a key role in preventing feet and ankle WMSDs.

Objective:To explore the structural relationship between WMSDs in the upper limbs and various risk factors in the occupational population in China, based on a large sample epidemiological survey and structural equation analysis, and to establish a structural equation model, so as to lay a foundation for the prevention and control of such diseases.Methods:The Chinese version of the Musculoskeletal Disorders Electronic Questionnaire was used to conduct a nationwide survey on the prevalence of WMSDs in the upper extremity. Six factors related to WMSDs in the upper extremity were extracted by the classification standard of adverse ergonomic factors and their source and confirmatory factor analysis, including work organization, work type, upper extremity work posture, individual factors, upper extremity fatigue and upper extremity WMSDs. The structural equation analysis was carried out and the structural equation model was established.Results:The incidence of WMSDs and fatigue in the upper limbs was 24.44% and 43.76%, respectively. The adjusted structural equation model fitting indicators were generally up to the standard (GFI=1.000, AGFI=1.000, RMSEA=0.043, NFI=0.808, TLI=0.784) . The four exogenous latent variables of work organization, work type, upper limb work posture and individual factors were correlated. There was a strong positive correlation between job type and upper limb work posture ( r=0.865) , a moderate positive correlation between work organization and job type and upper limb work posture ( r=0.570, 0.490) , and a weak negative correlation between individual factors and the other three exogenous latent variables. Upper limb work posture and individual factors had direct effects on upper limb WMSDs, and the effect coefficients were 0.10 and 0.06, respectively. Upper limb fatigue played a mediating role between work organization, work type, upper limb work posture and upper limb WMSDs. The effect coefficient was 0.46, and the composition ratios of indirect effects were 100.0%, 100.0%, and 38.3%, respectively. The direct path effect of upper limb work posture, individual factors and upper limb WMSDs was weaker than the mediating path through upper limb fatigue. Conclusion:When carrying out the prevention and control of upper limbWMSDs, it is necessary to comprehensively consider the pathogenesis path of upper limb muscle fatigue and upper limb WMSDs caused by work organization, work type, and upper limb work posture, so as to provide theoretical reference for improving the prevention and control level of such diseases.