Ergonomic Principle for the Prevention of Work-Related Musculoskeletal Disorders Part 1: General Principles (T/WSJD 14.1-2020) is the first guideline standard for the prevention of work-related musculoskeletal disorders provided to employers and occupational health technical service institutions in China, which covers ergonomic risk factors and their hazard definition, ergonomic prevention principles, risk assessment process, risk control process and risk evaluation principles. The standard specifically clarify the specific types of adverse ergonomic risk factors and control strategies and the standard process of systematic ergonomic risk assessment, providing implementation paths and practical guidance for eliminating/reducing adverse ergonomic risks and enhance workplace environments to prevent work-related musculoskeletal disorders. This paper interprets and analyzes the background of standard establishment, formulation process, fundamental basis, and main content, etc., to provide scientific and accurate technical support for enterprise managers, labours and technical personnel of occupational health institutions to optimize the use of this standard.

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.

Ergonomic Principle for the Prevention of Work-Related Musculoskeletal Disorders Part 1: General Principles (T/WSJD 14.1-2020) is the first guideline standard for the prevention of work-related musculoskeletal disorders provided to employers and occupational health technical service institutions in China, which covers ergonomic risk factors and their hazard definition, ergonomic prevention principles, risk assessment process, risk control process and risk evaluation principles. The standard specifically clarify the specific types of adverse ergonomic risk factors and control strategies and the standard process of systematic ergonomic risk assessment, providing implementation paths and practical guidance for eliminating/reducing adverse ergonomic risks and enhance workplace environments to prevent work-related musculoskeletal disorders. This paper interprets and analyzes the background of standard establishment, formulation process, fundamental basis, and main content, etc., to provide scientific and accurate technical support for enterprise managers, labours and technical personnel of occupational health institutions to optimize the use of this standard.

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 predict and verify the mechanism of Naoan capsules(NAC)in treatment of ischemic stroke(IS)by network pharmacology,Gene Expression Omnibus(GEO)database,and molecular docking technology.Methods The active components in NAC were collected using the Traditional Chinese Medicine System Pharmacological Analysis Platform,and the disease-related differential genes were screened using GEO database.After screening and obtaining the common targets of the two,the compound disease network was constructed by Cytoscape 3.8.2 software.At the same time,protein-protein interaction networks were created to identify candidate targets for NAC treatment of IS,and gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses were performed.Finally,core targets were verified by molecular docking technology.Results A total of 56 candidate compounds and 18 544 disease-related differential genes were screened.Further,quercetin,kaempferol,luteolin and baicalein were found to be the key active compounds of NAC in the treatment of IS through the compound disease network.In the search of PPI network core,eight key targets for NAC treatment of IS were screened,including mitogen-activated protein kinase 1(MAPK1),B-cell lymphoma factor 2(Bcl-2),cysteinylaspartate specific protease 3(CASP3),etc.In addition,the key pathways of NAC treatment of IS are mainly concentrated in lipid and atherosclerosis,advanced glycation end products and receptor for advanced glycation end products(AGE-RAGE),tumor necrosis factor(TNF),interleukin17(IL-17),C-type lectin receptor,apoptosis,hypoxia-inducing factor-1(HIF-1),MAPK and other signaling pathways.Finally,the molecular docking results showed that the key active compounds(quercetin,kaempferol,luteolin and baicalein)had good binding force with the 8 key targets,which initially verified the results of network pharmacology.Conclusion NAC plays a role in the treatment of IS through multi-component,multi-target and multi-pathway.

Objective To develop a matrix metalloproteinase(MMP)-responsive hyaluronic acid(HA)-based controlled-release material for brain-derived neurotrophic factor(BDNF)to provide a novel therapeutic strategy for intervention and repair of traumatic brain injury(TBI).Methods HA was modified with amination,followed by condensation with Suflo-SMCC carboxyl group to form amide,and then linked with glutathione(GSH)to synthesize HA-GSH.The recombinant glutathione S-transferase(GST)-tissue inhibitor of metalloproteinase(TIMP)-BDNF(GST-TIMP-BDNF)expression plasmid was constructed using molecular cloning technique with double enzyme digestion by Bam H Ⅰ and Eco R Ⅰ.The recombinant GST-TIMP-BDNF protein was expressed in the Escherichia coli prokaryotic expression system,and purified by ion exchange chromatography,confirmed by Western blotting.MMP diluents were supplemented with PBS,MMP inhibitor marimastat,and varing concentrations(0.4,0.6,0.8 mg/ml)of GST-TIMP-BDNF or GST-BDNF.MMP-2 activity was analyzed using an MMP activity detection kit to evaluate the inhibitory effect of the recombinant protein on MMP.Primary rat neurons were extracted and cultured to establish an iron death model induced by RSL3.The effect of recombinant protein GST-TIMP-BDNF on neuronal injury was detected by immunofluorescence staining.Results MRI hydrogen spectrum identification confirmed the successful synthesis of HA-GSH.Western blotting results showed the successful expression of the recombinant protein GST-TIMP-BDNF containing the GST tag using the E.coli prokaryotic expression system.MMP activity detection results indicated that the recombinant protein GST-TIMP-BDNF had a superior inhibitory effect on MMP-2 activity compared to GST-BDNF(P<0.05).Immunofluorescence staining results showed a significant increase in fluorescence intensity in rat neurons treated with GST-TIMP-BDNF after RSL3 induction(P<0.05).Conclusion A MMP-responsive HA-based BDNF controlled-release material has been successfully developed,exhibiting a protective effect on neuron damage.

Objective To explore the regulatory role of transient receptor potential channel 6(TRPC6)on podocyte autophagy under the influence of homocysteine(Hcy)in mouse kidney.Methods Mouse renal podocytes were divided into control group and Hcy groups(stimulated by Hcy at 40,60,80 and 100 μmol/L for 48 h).The level of TRPC6 mRNA was assessed using quantitative reverse transcription polymerase chain reaction(qRT-PCR)to identify the optimal Hcy concentration for subsequent experiments.Western blotting was employed to evaluate the expression levels of autophagy-related proteins LC3 Ⅱ and p62,as well as the expression levels of podocyte structural proteins Nephrin and Podocin.The expression levels of TRPC6 mRNA and protein in both groups were determined using qRT-PCR,Western blotting and immunofluorescence.Transfections of cells with TRPC6 overexpression or interference were set as follows:(1)control group(untreated),negative control group of TRPC6 overexpression,and TRPC6 overexpression group;(2)control group(untreated),negative control group of TRPC6 interference,and TRPC6 interference group(si-1,si-2,si-3).The expression level of TRPC6 was detected using qRT-PCR.The cells after overexpressing or interfering of TRPC6 were further set as follows:(1)control group(untreated),Hcy group(80 μmol/L Hcy added),TRPC6 overexpression control+Hcy group,TRPC6 overexpression+Hcy group;(2)control group(untreated),Hcy group,TRPC6 interference control+Hcy group,and TRPC6 interference+Hcy group.The expression levels of p62,LC3 Ⅱ,and TRPC6 proteins were detected using Western blotting.Results qRT-PCR detection results showed that compared with control group,the expression level of TRPC6 mRNA in Hcy group increased with the increase of Hcy concentration,with the highest expression level observed at 80 μmol/L Hcy.Therefore,80 μmol/L Hcy was selected as the optimal concentration for intervention.At this time,the expression level of autophagy-related protein LC3 Ⅱ increased,and the expression level of p62 decreased(P<0.05).Western blotting results showed that compared with control group,the expression levels of podocyte-related proteins Nephrin and Podocin in Hcy group were significantly decreased(P<0.05).qRT-PCR results showed that compared with control group,the expression level of TRPC6 mRNA in Hcy group was significantly increased(P<0.05).Compared with negative control group for TRPC6 overexpression,both mRNA and protein expression levels of TRPC6 in TRPC6 overexpression group were significantly higher(P<0.05).Compared with negative control group for TRPC6 interference,both mRNA and protein expression levels of TRPC6 in TRPC6 interference group were significantly decreased(P<0.05).Western blotting results showed that compared with negative control group for TRPC6 overexpression,the expression level of autophagy-related protein LC3 Ⅱ in TRPC6 overexpression+Hcy group was significantly increased,and the expression level of p62 was significantly decreased(P<0.05).Compared with TRPC6 negative control+Hcy group for TRPC6 interference+Hcy,the expression level of autophagy-related protein LC3 Ⅱ in TRPC6 interference+Hcy group was significantly decreased,and the expression level of p62 was significantly increased(P<0.05).Conclusion Hcy can induce autophagy of renal podocytes.Inhibiting the expression of TRPC6 can significantly reduce the autophagy damage to podocytes.

Objective:To analyze the distribution characteristics of work-related musculoskeletal disorders (WMSDs) among the occupational population in China's key industries during the period from 2018 to 2023, and to provide data support for the formulation of targeted prevention strategies.Methods:Between January 1, 2018, and December 31, 2023, a cross-sectional epidemiological survey and a retrospective investigation were conducted in seven geographical regions of North China, East China, Central China, South China, Southwest China, Northwest China, and Northeast China, using a combination of epidemiological cross-sectional and retrospective surveys. The industries were stratified according to the degree of closeness to WMSDs, the size of the occupational population, and the importance of the national economy, and then cluster sampling was conducted according to the size of the enterprises (large, medium, and small) within each stratum. Representative enterprises were selected, and workers who had been employed for more than one year and met the inclusion criteria were selected as the study subjects. The survey subjects completed the Chinese version of the Musculoskeletal Disorders Survey Questionnaire online by scanning a QR code. A total of 88, 609 valid questionnaires were collected. Continuous data were described by means and standard deviations, and the standardized incidence rates of WMSDs were evaluated using chi-square tests to compare the standardized incidence rates of different body parts.Results:The standardized prevalence rate of WMSDs among the frontline working population in China was 36.7%, with the top three being the neck (21.37%), shoulders (18.23%), and lower back (14.92%). There was a statistically significant difference in the standardized prevalence rate of WMSDs between different body parts (χ 2=47577.82, P<0.05). The lowest standardized prevalence rate of WMSDs was found in the southeast coastal region of China (32.54%), while the highest was in the northwest (49.70%) and northeast regions (46.16%). The standardized prevalence rate of WMSDs decreased from 42.88% in 2018 to 29.94% in 2023. The micro-enterprise observation group had a higher concentration of WMSDs in the neck (20.66%), lower back (17.95%), and shoulders (17.79%), while the large enterprise observation group had a higher concentration in the neck (20.54%), shoulders (17.52%), and lower back (14.65%). Among the industries surveyed, the highest standardized prevalence rate of WMSDs was found in the healthcare industry (53.18%), followed by the toy manufacturing industry (50.54%), the automotive manufacturing industry (43.39%), general aviation services (42.71%), and the ship and related equipment manufacturing industry (40.56%). The standardized prevalence rate of WMSDs among women was significantly higher than that of men ( OR value=1.44, P<0.05). In addition, the standardized prevalence rate of WMSDs with multiple affected body parts (four or more body parts affected simultaneously) was higher, and the risk of WMSDs increased with subjective fatigue, showing a significant "S-shaped" trend (the OR value was 2.19, 3.16, 4.71, 5.49, and 3.97 when the RPE was 13, 15, 17, 19, and 20, respectively. χ 2trend=17.23, P<0.001) . Conclusion:The distribution characteristics of WMSDs in key industries in China show obvious differences in different parts, regions, time, enterprise scale, industry and population attributes. Agriculture, pharmaceutical manufacturing, packaging and decoration and other printing industries have a high proportion of WMSDs in multiple parts at the same time and in a single site. It is necessary to study and implement precise preventive measures according to specific regions, industries and enterprise scales, as well as the characteristics of multi-site WMSDs, so as to effectively protect the health and well-being of the working population.

Objective:To explore the occupational contact characteristics of work-related musculoskeletal disorders (WMSDs) among key occupational groups in China, assess the impact of occupational factors on the occurrence of WMSDs, and propose corresponding preventive strategies.Methods:Between January 1, 2018, and December 31, 2023, a cross-sectional epidemiological survey method was employed to retrospectively investigate the occurrence of WMSDs and related occupational factors. Valid questionnaire data from 88609 on-the-job workers in 441 enterprises across 29 industries or job types in seven regions of China were collected, and the relationship between WMSDs and various occupational factors was discussed using multifactorial logistic regression analysis. Odds ratios ( OR) and their 95% confidence intervals ( CI) were calculated to assess the impact of different factors on the risk of WMSDs occurrence, with all statistical tests performed as two-tailed tests, using P<0.05 as the criterion for statistical significance. Results:Among the surveyed subjects, 59989 were male, accounting for 67.7% (59989/88609) ; 28620 women, accounting for 32.3% (28620/88609). The standardized incidence rate of work related musculoskeletal disorders (WMSDs) in 9 parts of the body was statistically significant ( P<0.05) among different working age groups without considering specific parts. The average length of service for onset of WMSDs (regardless of location) is (4.52±2.67) years, and there is a statistically significant difference in the length of service for onset of WMSDs in different locations ( P<0.05). As the frequency of heavy object handling increases, the standardization rate and OR value of WMSDs in various parts show a significant increase trend. The incidence of WMSDs is significantly correlated with maintaining poor work posture for a long time, frequent repetitive operations, and heavy object handling ( OR=1.52, 1.45, 1.63, P<0.01) . Conclusion:This study reveals that the risk of WMSDs in China's occupational population shows a non-linear change with increasing length of service, especially with a significant increase in 10 to 25 years of service. Poor work posture, frequent repetitive operations, and heavy object handling are significantly correlated with WMSDs, providing a scientific basis for developing more accurate and effective prevention strategies for WMSDs.

Objective:To investigate the relationships and impacts between various occupational ergonomic hazards and hand and wrist fatigue, as well as work-related musculoskeletal disorders (WMSDs) of the hand and wrist, and to propose targeted preventive and intervention measures for adverse occupational ergonomic factors causing WMSDs of the hand and wrist.Methods:From 2018 to December 2023, a nationwide epidemiologic survey study of wrist WMSDs was conducted using the Chinese version of the electronic questionnaire system for musculoskeletal disorders.A total of 88, 609 valid questionnaires were collected. The exclusion criteria were as follows: patients with congenital spinal deformities, as well as those with wrist WMSDs caused by external injuries, infectious diseases, and malignant tumors. A total of 73, 497 questionnaires were finally included in the study analysis, with an effective questionnaire return rate of 82.5%. Exploratory factor analysis was used to analyze and summarize the factors affecting wrist WMSDs from the questionnaires, including individual factors, work organization, work type, wrist work posture, wrist fatigue, and wrist WMSDs as latent variables, and to hypothesize, fit, and validate the structural aspect model, as well as to conduct mediation effect analysis.Results:The incidence of WMSDs and fatigue in wrist was 12.19% and 16.30% respectively. The fitting indexes of the modified structural equation model were basically up to the standard (GFI was 0.981, AGFI was 0.973, RMSEA was 0.031, NFI was 0.863, IFI and CFI were 0.865). There is a correlation between individual factors, work organization, wrist working posture and work type. There was a low negative correlation between individual factors and other factors, and there was a positive correlation between work organization, work type and wrist WMSDs ( r=0.346, 0.295), and these two factors were positively correlated with wrist fatigue height ( r=0.862, 0.599), and were positively correlated with wrist working posture ( r=0.443, 0.620). There was moderate positive correlation between wrist working posture and wrist fatigue ( r=0.469). The three most influential factors on wrist WMSDs were work organization, individual factor and work type, and the path coefficients were 0.247, 0.210 and 0.136, respectively. The first two factors that have the greatest influence on wrist fatigue are work organization and work type, and the path coefficients are 0.758 and 0.188, respectively. Individual factors, work type, wrist working posture and work organization had direct effects on wrist WMSDs, and the effect values were 0.093, 0.253, 0.718 and 0.583, respectively. Wrist fatigue played a partial mediating role between individual factors, work type, wrist working posture and work organization and wrist WMSDs, with the indirect effect ratio of 25.6%, 45.8%, 3.2% and 65.5%. Conclusion:Wrist fatigue plays an important mediating role in the path of various factors affecting wrist WMSDs, especially in the path of work organization, work type, individual factors and wrist WMSDs. Poor wrist working posture is an important risk factor that directly affects the occurrence of wrist WMSDs.