1.Status and correlations of psychological distress, job satisfaction, and sleep quality among prehospital emergency medical personnel in Guangzhou
Jiarui LIANG ; Huilin JIANG ; Baoling WU ; Hanxiang GONG ; Jiangli WU ; Tongtong DENG ; Zhengyu CHEN ; Xiaohui CHEN
Journal of Environmental and Occupational Medicine 2026;43(5):614-620
Background Prehospital emergency medical personnel (PEMP) are exposed to long-term high-pressure work, which can exacerbate psychological distress and impair job satisfaction and sleep quality. However, in-depth research on the interactions among these factors is lacking. Objective To assess the status of psychological distress, job satisfaction, and sleep quality of PEMP in Guangzhou and to explore the mediating role of sleep quality in the relationship between psychological distress and job satisfaction. Methods From February to May 2025, 1085 PEMP from "120" emergency network hospitals in Guangzhou were selected using convenience sampling. Data were collected via the General Information Questionnaire, Kessler Psychological Distress Scale, Minnesota Satisfaction Questionnaire, and Pittsburgh Sleep Quality Index. Statistical analyses were performed using SPSS 25.0, and The mediation model of sleep quality in linking psychological distress and job satisfaction was constructed using AMOS 28.0. The bias-corrected Bootstrap method was employed to assessed the significance of the mediating effect. Results A total of 1063 valid responses were received (97.97% valid response rate). The mean scores were: psychological distress (27.99±10.75), job satisfaction (69.45±15.84), and sleep quality (9.82±4.47). Significant differences in the three scores were found across gender, age, monthly night shift frequency, and hospital grade (P<0.05). Higher job satisfaction was linked to lower psychological distress and better sleep quality and its dimensions, while psychological distress directly correlated with poorer sleep quality (P<0.01). Sleep quality partially mediated the relationship between psychological distress and job satisfaction, with a mediating effect of −0.195, accounting for 43.62% of the total effect. Conclusion The participants report moderate psychological distress, moderate-to-high job satisfaction, and poor sleep quality. Psychological distress directly affects job satisfaction and indirectly through its impact on sleep quality. Interventions aimed at improving sleep health and mental health are essential to improve personnel well-being and work efficiency.
2.Status and correlations of psychological distress, job satisfaction, and sleep quality among prehospital emergency medical personnel in Guangzhou
Jiarui LIANG ; Huilin JIANG ; Baoling WU ; Hanxiang GONG ; Jiangli WU ; Tongtong DENG ; Zhengyu CHEN ; Xiaohui CHEN
Journal of Environmental and Occupational Medicine 2026;43(5):614-620
Background Prehospital emergency medical personnel (PEMP) are exposed to long-term high-pressure work, which can exacerbate psychological distress and impair job satisfaction and sleep quality. However, in-depth research on the interactions among these factors is lacking. Objective To assess the status of psychological distress, job satisfaction, and sleep quality of PEMP in Guangzhou and to explore the mediating role of sleep quality in the relationship between psychological distress and job satisfaction. Methods From February to May 2025, 1085 PEMP from "120" emergency network hospitals in Guangzhou were selected using convenience sampling. Data were collected via the General Information Questionnaire, Kessler Psychological Distress Scale, Minnesota Satisfaction Questionnaire, and Pittsburgh Sleep Quality Index. Statistical analyses were performed using SPSS 25.0, and The mediation model of sleep quality in linking psychological distress and job satisfaction was constructed using AMOS 28.0. The bias-corrected Bootstrap method was employed to assessed the significance of the mediating effect. Results A total of 1063 valid responses were received (97.97% valid response rate). The mean scores were: psychological distress (27.99±10.75), job satisfaction (69.45±15.84), and sleep quality (9.82±4.47). Significant differences in the three scores were found across gender, age, monthly night shift frequency, and hospital grade (P<0.05). Higher job satisfaction was linked to lower psychological distress and better sleep quality and its dimensions, while psychological distress directly correlated with poorer sleep quality (P<0.01). Sleep quality partially mediated the relationship between psychological distress and job satisfaction, with a mediating effect of −0.195, accounting for 43.62% of the total effect. Conclusion The participants report moderate psychological distress, moderate-to-high job satisfaction, and poor sleep quality. Psychological distress directly affects job satisfaction and indirectly through its impact on sleep quality. Interventions aimed at improving sleep health and mental health are essential to improve personnel well-being and work efficiency.
3.Curcumin extraction and preparation and optimization of curcumin nanoparticles
Yuhang WANG ; Han ZHANG ; Chaojing ZHANG ; Xurong KOU ; Tongtong JING ; Rimei LIN ; Xinyu LIU ; Shilei LOU ; Hui YAN ; Cong SUN
Chinese Journal of Tissue Engineering Research 2026;30(2):362-374
BACKGROUND:Curcumin is the main active ingredient of turmeric and has significant medicinal value in anti-tumor,anti-inflammatory,antioxidant and other aspects.However,its poor water solubility,unstable chemical properties and easy decomposition lead to difficulty in extracting curcumin and low extraction yield.Therefore,it is particularly important to optimize the curcumin extraction method.OBJECTIVE:To enhance the extraction yield and utilization value of curcumin and optimize the curcumin extraction process and curcumin nanoparticle preparation process.METHODS:Curcumin was extracted from turmeric by ethanol extraction,ultrasonic extraction,ionic liquid extraction,enzyme extraction,and ionic liquid combined with ultrasonic assisted enzyme extraction.The curcumin extraction yield was detected by high performance liquid chromatography;the best extraction method was determined,and subsequent process optimization experiments were carried out.The curcumin extraction yield was the response value with the type of ionic liquid,reaction temperature,ultrasonic time,liquid-to-solid ratio,ionic liquid concentration,and enzyme-drug mass ratio as parameters.The optimal production process of ionic liquid combined with ultrasonic assisted enzyme extraction was determined by single factor combined response surface experiment.The optimal process for preparing curcumin nanoparticles by ionic crosslinking method was determined by single factor combined response surface experiment with acetic acid concentration,chitosan to sodium tripolyphosphate mass ratio,stirring rate,curcumin mass concentration,sodium tripolyphosphate mass concentration,and chitosan mass concentration as parameters,and drug encapsulation efficiency as response value.Curcumin nanoparticles were prepared under the optimal process,and the particle size,polydispersity index,Zata potential value,drug loading,stability,hemolysis rate,and antioxidant capacity in vivo and in vitro of the nanoparticles were detected.RESULTS AND CONCLUSION:(1)Among the five extraction methods,the curcumin yield of ionic liquid combined with ultrasound-assisted enzyme extraction was the highest,and this method was selected as the curcumin extraction method for subsequent experiments.The results of single factor combined response surface experiment showed that the optimal process for curcumin extraction was:ionic liquid selected 1-hexyl-3-methylimidazolium chloride,reaction temperature 55 ℃,liquid-to-solid ratio 40 mL/g,ultrasound time 57 minutes,ionic liquid concentration 57%,enzyme-drug mass ratio 3.5:10,and the obtained turmeric extraction yield was 3.10%.The optimal preparation process of curcumin nanoparticles was:glacial acetic acid concentration 0.5%,chitosan and sodium tripolyphosphate mass ratio 5.0:1,stirring speed 150 r/min,curcumin mass concentration 2.23 mg/mL,sodium tripolyphosphate mass concentration 1.45 mg/mL,chitosan mass concentration 3.63 mg/mL,and the obtained drug encapsulation efficiency was 90.61%.(2)The drug loading of curcumin nanoparticles was(14.49±0.23)%,the average particle size was(76.95±1.65)nm,the polydispersity coefficient was 0.15±0.02,and the Zata potential value was(32.37±1.46)mV.The curcumin nanoparticles had good stability and blood compatibility,did not induce hemolysis,and had stronger antioxidant capacity in vivo and in vitro than free curcumin.(3)The results show that the process optimization not only solves the problems of low extraction yield,poor solubility,and low bioavailability of curcumin,but also enhances its antioxidant activity in vivo and in vitro.
4.Curcumin extraction and preparation and optimization of curcumin nanoparticles
Yuhang WANG ; Han ZHANG ; Chaojing ZHANG ; Xurong KOU ; Tongtong JING ; Rimei LIN ; Xinyu LIU ; Shilei LOU ; Hui YAN ; Cong SUN
Chinese Journal of Tissue Engineering Research 2026;30(2):362-374
BACKGROUND:Curcumin is the main active ingredient of turmeric and has significant medicinal value in anti-tumor,anti-inflammatory,antioxidant and other aspects.However,its poor water solubility,unstable chemical properties and easy decomposition lead to difficulty in extracting curcumin and low extraction yield.Therefore,it is particularly important to optimize the curcumin extraction method.OBJECTIVE:To enhance the extraction yield and utilization value of curcumin and optimize the curcumin extraction process and curcumin nanoparticle preparation process.METHODS:Curcumin was extracted from turmeric by ethanol extraction,ultrasonic extraction,ionic liquid extraction,enzyme extraction,and ionic liquid combined with ultrasonic assisted enzyme extraction.The curcumin extraction yield was detected by high performance liquid chromatography;the best extraction method was determined,and subsequent process optimization experiments were carried out.The curcumin extraction yield was the response value with the type of ionic liquid,reaction temperature,ultrasonic time,liquid-to-solid ratio,ionic liquid concentration,and enzyme-drug mass ratio as parameters.The optimal production process of ionic liquid combined with ultrasonic assisted enzyme extraction was determined by single factor combined response surface experiment.The optimal process for preparing curcumin nanoparticles by ionic crosslinking method was determined by single factor combined response surface experiment with acetic acid concentration,chitosan to sodium tripolyphosphate mass ratio,stirring rate,curcumin mass concentration,sodium tripolyphosphate mass concentration,and chitosan mass concentration as parameters,and drug encapsulation efficiency as response value.Curcumin nanoparticles were prepared under the optimal process,and the particle size,polydispersity index,Zata potential value,drug loading,stability,hemolysis rate,and antioxidant capacity in vivo and in vitro of the nanoparticles were detected.RESULTS AND CONCLUSION:(1)Among the five extraction methods,the curcumin yield of ionic liquid combined with ultrasound-assisted enzyme extraction was the highest,and this method was selected as the curcumin extraction method for subsequent experiments.The results of single factor combined response surface experiment showed that the optimal process for curcumin extraction was:ionic liquid selected 1-hexyl-3-methylimidazolium chloride,reaction temperature 55 ℃,liquid-to-solid ratio 40 mL/g,ultrasound time 57 minutes,ionic liquid concentration 57%,enzyme-drug mass ratio 3.5:10,and the obtained turmeric extraction yield was 3.10%.The optimal preparation process of curcumin nanoparticles was:glacial acetic acid concentration 0.5%,chitosan and sodium tripolyphosphate mass ratio 5.0:1,stirring speed 150 r/min,curcumin mass concentration 2.23 mg/mL,sodium tripolyphosphate mass concentration 1.45 mg/mL,chitosan mass concentration 3.63 mg/mL,and the obtained drug encapsulation efficiency was 90.61%.(2)The drug loading of curcumin nanoparticles was(14.49±0.23)%,the average particle size was(76.95±1.65)nm,the polydispersity coefficient was 0.15±0.02,and the Zata potential value was(32.37±1.46)mV.The curcumin nanoparticles had good stability and blood compatibility,did not induce hemolysis,and had stronger antioxidant capacity in vivo and in vitro than free curcumin.(3)The results show that the process optimization not only solves the problems of low extraction yield,poor solubility,and low bioavailability of curcumin,but also enhances its antioxidant activity in vivo and in vitro.
5.A menstrual diary-based investigation of dysmenorrhea symptoms among female medical students
Bingbing SUN ; Xuan LU ; Tongtong XIAO ; Hui TAN ; Xu QIAN
Shanghai Journal of Preventive Medicine 2026;38(6):458-462
ObjectiveTo describe the prevalence and dynamic pain characteristics of dysmenorrhea among female medical students through a menstrual diary-based observational study. MethodsFrom April to June 2021, female students were recruited from a medical college in Shanghai to complete menstrual diaries and record dysmenorrhea-related characteristics for two menstrual cycles. Dysmenorrhea severity was assessed using the visual analogue scale (VAS) (no pain: 0; mild: 1‒3; moderate: 4‒6; severe: 7‒10). A total of 323 diaries were collected, of which 303 were 93.81% valid (valid response rate: 93.81%), covering 596 complete menstrual cycles. Among them, 293 participants completed diaries for two cycles and were included in the analysis of persistent dysmenorrhea. Period, point, and persistent prevalence of dysmenorrhea were calculated using the number of participants as the denominator. Paired comparisons were performed using Cochran’s Q test and Bonferroni-adjusted McNemar tests. Using menstrual cycles with dysmenorrhea as the unit of analysis, the distributions of pain onset, peak timing, and pain duration across different severities were compared using the χ² tests or Fisher’s precision probability tests. ResultsAmong 303 female college students, 269 experienced dysmenorrhea during the first recorded cycle, and 288 had dysmenorrhea in any cycle. Among 596 complete menstrual cycles recorded, 527 were associated with dysmenorrhea (88.42%), and among 293 students who completed 2 complete recorded cycles, 239 had persistent dysmenorrhea. The period, point, and persistent prevalence of dysmenorrhea among female college students were 95.05% (288/303), 88.78% (269/303), and 81.57% (239/293), respectively (Q=61.61, P<0.001). The prevalence of persistently severe dysmenorrhea was 5.12% (15/293). Among the 527 dysmenorrheic cycles, there were statistically significant differences in the distribution of pain onset time (P=0.003) and pain duration (P<0.001) among different degrees of dysmenorrhea; mild dysmenorrhea mostly started on the first day of menstruation (52.83%), and moderate dysmenorrhea mostly started before menstruation (50.19%). Pain duration increased with severity; the proportions of cycles with pain lasting ≥4 days were 13.20%, 43.03%, and 51.56% for mild, moderate, and severe dysmenorrhea cycles, respectively. For all severity groups, mean pain scores peaked on the first day of menstruation and then decreased day by day to a stable level. ConclusionDysmenorrhea is highly prevalent among female medical students, and differences exist across pain severity levels in onset time, duration, and dynamic changes in pain. Identification and health guidance for those with persistently moderate-to-severe dysmenorrhea should be strengthened, and medical evaluation should be conducted when necessary.
6.Application of ICF in visual impairment rehabilitation: a scoping review
Tongtong WEI ; Yifan TIAN ; Ting CHEN ; Qi YAO ; Jianmin HU
Chinese Journal of Rehabilitation Theory and Practice 2026;32(9):1025-1032
ObjectiveTo review the application of the International Classification of Functioning, Disability and Health (ICF) in the field of visual impairment (VI) rehabilitation. MethodsLiterature related to ICF and VI rehabilitation was retrieved from PubMed, Web of Science, CNKI, Wanfang Data, and VIP from inception to May, 2026. Standards and policy documents related to VI published before May, 2026 were retrieved from the National Standards Full-text Disclosure System of the Standardization Administration of China, the China Disabled Persons' Federation and the Chinese Government Portal. Following PRISMA-ScR, based on the three-dimensional ICF framework, an integrated analysis was conducted from the dimensions of theory, practice and policy. ResultsA total of 17 articles involving 2 648 participants, and four domestic VI assessment standards and one guideline were included. At the theoretical level, domestic VI standards showed the highest alignment with the ICF dimension of body functions, while the coverage of the activities and participation dimension was uneven, and the coverage of the environmental factors dimension was the weakest. At the practical level, the ICF was primarily used for developing assessment tools, conducting clinical evaluations, implementing interventions and exploring service models. At the policy level, the overall orientation of domestic special education and medical insurance payment aligned with the ICF concept of whole person rehabilitation, yet specific implementation rules remained to be formulated. ConclusionICF provides a comprehensive and systematic approach for integrating the VI rehabilitation system in China, demonstrating significant application value in standard construction, clinical practice optimization and policy refinement.
7.Characteristics and prognosis of patients with primary sclerosing cholangitis
Sha CHEN ; Tongtong MENG ; Weijia DUAN ; Shuxiang LI ; Tingting LYU ; Yu WANG ; Jidong JIA ; Yuanyuan KONG ; Hong YOU
Chinese Journal of Internal Medicine 2025;64(3):206-211
Objective:Primary sclerosing cholangitis (PSC) is a rare autoimmune disease. This study aims to describe the baseline characteristics and clinical outcomes of Chinese PSC patients and explore risk factors associated with prognosis, addressing the lack of long-term prognostic analysis in China.Methods:Clinical data of PSC patients were retrospectively collected from May 2009 to June 2023 in Beijing Friendship Hospital Affiliated to Capital Medical University, and patient follow-up was conducted through outpatient visits, telephone calls, and medical record reviews. The Cox proportional hazards model and the Kaplan-Meier method were employed to identify risk factors and estimate transplant-free survival.Results:A total of 65 PSC patients were enrolled, with male patients accounting for 50.8% and an average age of onset of 44 years. The disease types primarily included large duct PSC (57.9%) and whole duct PSC (22.8%). Most patients (78.5%) sought medical attention due to symptoms, with common clinical manifestations including jaundice (32.3%), fatigue (23.1%), abdominal discomfort (21.5%), pruritus (16.9%), and fever (10.8%). A total of 19 patients (29.2%) had concomitant ulcerative colitis. Compared to large duct PSC or whole duct PSC, small duct PSC showed a lower proportion of concomitant ulcerative colitis ( P<0.001) and milder baseline disease severity. After a median follow-up of 29 months (interquartile range: 11,53), 19 patients experienced liver transplantations and/or liver disease-related deaths. The overall 2-year and 5-year transplant-free survival rates for PSC patients were 76.0% and 59.5%, respectively. Elevated bile acid levels were identified as an independent risk factor for poor outcomes in PSC patients. Conclusion:The study population of Chinese PSC patients predominantly consisted of middle-aged males, characterized by a low ratio of asymptomatic cases, a low incidence of associated inflammatory bowel disease, and a low rate of transplant-free survival. Elevated bile acid level was identified as an independent risk factor for poor outcomes in PSC patients.
8.A case of kidney transplant patient with chronic diarrhea caused by Cyclospora cayetanensis infection
Yuanyuan XU ; Tongtong XU ; Muyun WEI ; Min LI ; Changsheng WANG
Chinese Journal of Laboratory Medicine 2025;48(3):409-411
A 66-year-old female kidney transplant recipient presented to Shanghai Jiao Tong University Affiliated Renji Hospital on May 24th, 2024 due to recurring intermittent diarrhea for over 16 years. The parasites were found through examination of small intestinal fluid. Small intestinal fluid mNGS combined with blood mNGS confirmed Cyclospora cayetanensis infection. The cause of the diarrhea was clarified. Oral compound sulfamethoxazole was used as treatment, and the patient's diarrhea symptoms improved, and no Cyclospora cayetanensis was found in the small intestinal fluid smear three consecutive times. Parasitic infection factors should be excluded in patients with low immune function and chronic diarrhea. Non-invasive small intestinal fluid smear combined with mNGS detection provides a new method to clarify the cause of chronic diarrhea.
9.Analysis of microbial community composition of lower respiratory tract in patients with severe hospital-acquired pneumonia in critical care
Tongtong ZHENG ; Min WANG ; Qi SHAN ; Minghang LI ; Yazhen BAI ; Qizhi FU
Tianjin Medical Journal 2025;53(11):1145-1151
Objective To investigae microbial community structure of lower respiratory tract in severe hospital-acquired pneumonia(SHAP)patients in intensive care unit(ICU)using metagenomic next-generation sequencing(mNGS).Methods mNGS was performed on bronchoalveolar lavage fluid(BALF)of 84 patients with SHAP.Patients were grouped based on age,smoking status,underlying diseases and duration of artificial airway.The differences in α diversity,β diversity,microbial composition and community structure of airway microbiota were compared between different groups.The differential airway microbiota associated with artificial airway were screened,and microbial co-occurrence networks was constructed to observe the interaction in microorganisms.Results Results of α diversity analysis revealed that diversity and evenness of the microbial community were higher in young adults compared to those of middle-aged patients,while microbial diversity and evenness were significantly reduced in patients with comorbid stroke.In the group of artificial airway treatment,the diversity and uniformity of microorganisms decreased as the duration of artificial airway treatment increased.The diversity was the lowest when the artificial airway treatment lasted for more than 3 days.β diversity analysis confirmed that there were significant differences in the distinct microbial community structures between the>3 days support group and the non-intubated and≤3 days support cohorts.Acinetobacter baumannii was dominant in all groups.The bacterial diversity was significantly higher in the middle-aged group,the non-smoking group,the group without artificial airway therapy,the group without diabetes mellitus,the group with artificial airway therapy≥3 days and the group with chronic lung disease than those of other groups.In particular,pseudomonas aeruginosa,corynebacterium striatum and veillonella parvula were enriched in these groups.Difference analysis showed that there were significant differences in pseudomonas aeruginosa and corynebacterium striatum between the group with artificial airway treatment>3 days,the group without artificial airway therapy and the group with artificial airway treatment≤3 days.Network co-occurrence showed that there may be synergistic or antagonistic relationships between some microorganisms.Conclusion The microbial diversity of the lower respiratory tract in patients with SHAP significantly decreases in the elderly,those with concurrent stroke and those receiving artificial airway treatment.For these groups,rational use of antibiotics should be adopted to guide precise anti-infection treatment.
10.CHK1 attenuates cardiac senescence of mice through activating Rap1/Nox4 mediated oxidative stress homeostasis
Peng JING ; Liuhua ZHOU ; Yixi CHEN ; Lingfeng GU ; Chong DU ; Tongtong YANG ; Shuxuan CHEN ; Hao WANG ; Liansheng WANG
Chinese Journal of Cardiology 2025;53(12):1411-1421
Objective:To investigate the biological role and molecular mechanism of checkpoint kinase 1 (CHK1) in delaying cardiac aging in mice.Methods:In vitro, a senescence model of H9C2 cells (a cardiomyocyte line) was induced using H 2O 2. A control group (without H 2O 2 treatment) and three H 2O 2-treated groups (at concentrations of 10, 30, and 50 μmol/L) were set up. The CCK-8 assay was used to evaluate the proliferative activity of cells in each group; Western blot analysis was employed to detect the expression level of CHK1; and quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to determine the messenger RNA (mRNA) expression levels of P16 and interleukin-1β (IL-1β). In vivo, C57BL/6 wild-type mice aged 2 months ( n=15) and 24 months ( n=40), as well as myocardial-specific CHK1-overexpressing (CHK1-TG) mice aged 2 months ( n=15) and 24 months ( n=40), were selected. The mice were divided into four groups based on age and genotype: 2-month-old wild-type (WT-2M), 24-month-old wild-type (WT-24M), 2-month-old CHK1-TG (CHK1-TG-2M), and 24-month-old CHK1-TG (CHK1-TG-24M). Echocardiography was used to evaluate cardiac function of mice in the WT-24M and CHK1-TG-24M groups. Western blot analysis was conducted to measure the protein expression levels of CHK1, total Ras-related protein 1 (Rap1), NADPH oxidase 4 (Nox4), and Rap1-guanosine triphosphate (Rap1-GTP, the active form of Rap1) in the cardiac tissue of mice in each group. qRT-PCR was used to detect the messenger RNA (mRNA) expression levels of CHK1, collagen type Ⅰ (Coll1), matrix metalloproteinase-2 (Mmp2), alpha-smooth muscle actin (α-SMA), P53, P21, P16, thioredoxin 1 (Trx1), thioredoxin reductase (TrxR), glutathione recluctase (GR), Rap1, and Nox4. Immunofluorescence staining was employed to determine the protein expression levels of P53, P21, and P16, as well as the proportion of histone H2AX phosphorylation-positive cells. Dihydroethidium (DHE) staining was used to detect the relative intensity of DHE. Wheat germ agglutinin staining, HE staining, Masson staining and Sirius red staining were applied to measure the cross-sectional area of cardiomyocytes, cardiac morphology, and myocardial fibrosis area. Mice in the WT-24M and CHK1-TG-24M groups were intraperitoneally injected with the Rap1 activity inhibitor GGTI298 (25 μmol/kg). After injection, the oxidative stress damage in the cardiac tissue of the mice was detected, along with the mRNA expression levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P16, P21, and P53). Results:A concentration of 30 μmol/L was determined as the optimal concentration for establishing an H 2O 2-induced senescence model of myocardial cells in vitro. The expression level of CHK1 in H9C2 cells of the 30 μmol/L H 2O 2 group was lower than that in the control group ( P<0.05). Echocardiographic examination showed that the left ventricular ejection fraction ((61.08±1.13)% vs. (52.55±2.02)%) and fractional shortening ((31.80±1.27)% vs. (25.18±1.59)%) of mice in the CHK1-TG-24M group were higher than those in the WT-24M group (both P<0.05). qRT-PCR and Western blot analysis revealed that, compared with the WT-24M group, mice in CHK1-TG-24M group had higher expression levels of CHK1 and its mRNA, lower expression levels of Nox4 and its mRNA, and higher expression level of Rap1-guanosine triphosphate (Rap1-GTP) (all P<0.05). However, there were no statistically significant differences in the total expression level of Rap1 and its mRNA between the two groups (both P>0.05). In addition, the mRNA expression levels of Coll1, Mmp2, and α-SMA in myocardial tissue of mice in the CHK1-TG-24M group were lower than those in the WT-24M group (all P<0.05). Immunofluorescence staining results showed that the expression levels of P53, P21, and P16 proteins, as well as the proportion of phosphorylated histone H2AX-positive cells in myocardial tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). qRT-PCR further confirmed that the mRNA expression levels of the above-mentioned proteins in cardiac tissue of mice in the WT-24M group were higher than those in the CHK1-TG-24M group (all P<0.05). DHE staining results indicated that the relative intensity of DHE in cardiac tissue of mice in the CHK1-TG-24M group was lower than that in the WT-24M group ( P<0.05). Meanwhile, the left ventricular internal diameter, cross-sectional area of cardiomyocytes, and myocardial fibrosis area of mice in the CHK1-TG-24M group were all smaller than those in the WT-24M group (all P<0.05). Furthermore, the degree of DNA damage in cardiac tissue as well as the mRNA levels of fibrosis-related indicators (Coll1, Mmp2, and α-SMA) and cell cycle inhibitory proteins (P53, P21, P16) in mice of the WT-24M+GGTI298 group were higher than those in the WT-24M group and the CHK1-TG-24M+GGTI298 group (all P<0.05). Conclusion:CHK1 alleviates oxidative stress-induced damage in mouse cardiomyocytes by activating the Rap1/Nox4 signaling pathway, thereby delaying cardiac aging in mice.

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