1.Novel Structural Features of Isoflavone Synthase from Medicago truncatula Shed Light on Its Unique Enzymatic Mechanism
Chao SHI ; Zhao-Yang YE ; Fei XU ; Xiang-Ning DU ; Zhang-Xin CHEN ; Ming-Yue GU ; Jie DENG ; Wei WANG ; Liang-Yu LIU ; Mei-Ying WANG ; Xiao-Dong SU ; He-Li LIU ; Ming-Ying SHANG ; Li-Xin HUANG ; Zhen-Zhan CHANG
Chinese Journal of Biochemistry and Molecular Biology 2025;41(8):1204-1213,中插1-中插6
Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 ? by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Ⅰa-loop-helix Ⅰβ motif which cor-responds to helix Ⅰ of other P450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,the γ-domain.The structure reveals a homodimer in which the γ-domain of one molecule interacts with the β-domain of another.The plane of heme group makes an angle of ap-proximately 40° with the helix Ⅰa-loop-helix Ⅰβ motif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recogni-tion.Phe-301,Ser-303 and Gly-305 from the helix Ⅰa-loop-helix Ⅰβ motif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.
2.Comparative effectiveness of small optical zone orthokeratology lenses and repeated low-level red-light therapy for controlling myopia in adolescents
Shi-mei LIU ; Li CHEN ; Da LUO ; Qi-hui LUO ; Yu CHENG ; Ren-xiang TANG ; Wei YANG ; Bo LIU
Journal of Regional Anatomy and Operative Surgery 2025;34(11):972-976
Objective To compare the effect of small optical zone orthokeratology lenses(OK lenses)and repeated low-level red-light(RLRL)therapy in controlling myopia progression for adolescents,and the therapeutic effectiveness of RLRL is evaluated.Methods A retrospective analysis was conducted on the clinical data of 80 adolescent myopic patients in the First Affiliated Hospital of Army Medical University.The patients were divided into the RLRL group and the OK lenses group according to different intervention methods,with 40 cases in each group.Patients in the RLRL group received RLRL therapy combined with single-vision spectacles,and patients in the OK lenses group were treated with OK lenses.The changes of spherical equivalent(SE),axial length and subfoveal choroidal thickness(SFCT)1,3,6,and 12 months after treatment compared with the baseline,and color vision of patients were assessed.Based on the mean baseline axial length of the RLRL group,the patients in this group were subdivided into the short axial group and the long axial group,and the changes of the axial length and SFCT were further analyzed.Results The diopter 1,3,6,and 12 months after treatment in the RLRL group were not significantly different from the baseline(P>0.05).Axial lengths of patients in the RLRL group progressively shortened after treatment and returned close to the baseline 12 months after treatment.In contrast,axial lengths of patients in the OK lens continued to grow within 12 months after treatment;the axial lengths at each time point after treatment of patients in the two groups were significantly different from the baseline(P<0.05).The changes of axial length of patients in the RLRL group at each time point after treatment were significantly smaller than those in the OK lenses group(P<0.05).The SFCT changes of patients in the RLRL group at each time point after treatment were all greater than those in the OK lenses group(P<0.05).The SFCT at each time point after treatment in the RLRL group were significantly different from the baseline(P<0.05),whereas the SFCT at each time point after treatment in the OK lenses group were not significantly different from the baseline(P>0.05).The changes of axial length at each time point after treatment of patients in the long axial group were all greater than those in the short axial group(P<0.05);the SFCT changes 6 months after treatment of patients in the long axial group was greater than that in the short axial group(P<0.05);the SFCT at each time point after treatment of patients in the two groups were signifi-cantly different from the baseline(P<0.05).Color vision tests revealed no abnormities after treatment in the RLRL group and the OK lenses group.Conclusion RLRL therapy is effective in controlling myopia progression and demonstrates superior axial length control compared to orthokeratology lenses.
3.Novel Structural Features of Isoflavone Synthase from Medicago truncatula Shed Light on Its Unique Enzymatic Mechanism
Chao SHI ; Zhao-Yang YE ; Fei XU ; Xiang-Ning DU ; Zhang-Xin CHEN ; Ming-Yue GU ; Jie DENG ; Wei WANG ; Liang-Yu LIU ; Mei-Ying WANG ; Xiao-Dong SU ; He-Li LIU ; Ming-Ying SHANG ; Li-Xin HUANG ; Zhen-Zhan CHANG
Chinese Journal of Biochemistry and Molecular Biology 2025;41(8):1204-1213,中插1-中插6
Isoflavones which mainly distributed in leguminous plants have plenty of health benefits.Isoflavone synthase(IFS)is a membrane-associated cytochrome P450 enzyme(CYP450)which carries out the unique aryl-ring migration and hydroxylation.So far,few crystal structures of plant P450s have been obtained.We determined the crystal structure of IFS from Medicago truncatula at 1.9 ? by MAD method using a selenomethionine substituted crystal and conducted molecular docking and mutagenesis study.The structure of IFS complexed with imidazole exhibits the helix Ⅰa-loop-helix Ⅰβ motif which cor-responds to helix Ⅰ of other P450s.Compared with structures of common P450s,IFS/imidazole structure contains an extra domain,i.e.,the γ-domain.The structure reveals a homodimer in which the γ-domain of one molecule interacts with the β-domain of another.The plane of heme group makes an angle of ap-proximately 40° with the helix Ⅰa-loop-helix Ⅰβ motif.Molecular docking combined with mutagenesis study suggested that Trp-128 and Asp-300 might play important roles in substrate binding and recogni-tion.Phe-301,Ser-303 and Gly-305 from the helix Ⅰa-loop-helix Ⅰβ motif may play important roles in the aryl-ring migration.These novel structural features reveal insights into the unique reaction mechanism of IFS and provide a basis for engineering IFS in leguminous crops for health purpose.
4.Comparative effectiveness of small optical zone orthokeratology lenses and repeated low-level red-light therapy for controlling myopia in adolescents
Shi-mei LIU ; Li CHEN ; Da LUO ; Qi-hui LUO ; Yu CHENG ; Ren-xiang TANG ; Wei YANG ; Bo LIU
Journal of Regional Anatomy and Operative Surgery 2025;34(11):972-976
Objective To compare the effect of small optical zone orthokeratology lenses(OK lenses)and repeated low-level red-light(RLRL)therapy in controlling myopia progression for adolescents,and the therapeutic effectiveness of RLRL is evaluated.Methods A retrospective analysis was conducted on the clinical data of 80 adolescent myopic patients in the First Affiliated Hospital of Army Medical University.The patients were divided into the RLRL group and the OK lenses group according to different intervention methods,with 40 cases in each group.Patients in the RLRL group received RLRL therapy combined with single-vision spectacles,and patients in the OK lenses group were treated with OK lenses.The changes of spherical equivalent(SE),axial length and subfoveal choroidal thickness(SFCT)1,3,6,and 12 months after treatment compared with the baseline,and color vision of patients were assessed.Based on the mean baseline axial length of the RLRL group,the patients in this group were subdivided into the short axial group and the long axial group,and the changes of the axial length and SFCT were further analyzed.Results The diopter 1,3,6,and 12 months after treatment in the RLRL group were not significantly different from the baseline(P>0.05).Axial lengths of patients in the RLRL group progressively shortened after treatment and returned close to the baseline 12 months after treatment.In contrast,axial lengths of patients in the OK lens continued to grow within 12 months after treatment;the axial lengths at each time point after treatment of patients in the two groups were significantly different from the baseline(P<0.05).The changes of axial length of patients in the RLRL group at each time point after treatment were significantly smaller than those in the OK lenses group(P<0.05).The SFCT changes of patients in the RLRL group at each time point after treatment were all greater than those in the OK lenses group(P<0.05).The SFCT at each time point after treatment in the RLRL group were significantly different from the baseline(P<0.05),whereas the SFCT at each time point after treatment in the OK lenses group were not significantly different from the baseline(P>0.05).The changes of axial length at each time point after treatment of patients in the long axial group were all greater than those in the short axial group(P<0.05);the SFCT changes 6 months after treatment of patients in the long axial group was greater than that in the short axial group(P<0.05);the SFCT at each time point after treatment of patients in the two groups were signifi-cantly different from the baseline(P<0.05).Color vision tests revealed no abnormities after treatment in the RLRL group and the OK lenses group.Conclusion RLRL therapy is effective in controlling myopia progression and demonstrates superior axial length control compared to orthokeratology lenses.
5.Effect of short-chain fatty acid on perioperative cognitive dysfunction in aged rats through p38 MAPK/NF-κB p65 pathway
Xiang LIU ; Xiaona TAN ; Yaozong YU ; Junfang NIU ; Qiujun WANG ; Lei SHI
Chinese Journal of Behavioral Medicine and Brain Science 2025;34(1):9-15
Objective:To evaluate the effect of short-chain fatty acid(SCFA) on perioperative cognitive dysfunction in aged rats through mitogen-activated protein kinase p38(p38 MAPK)/nuclear factor-κB p65(NF-κB p65) pathway.Methods:According to random number table method, 32 healthy SPF-grade male SD rats, aged 16 months and weighing 520~620 g, were divided into control group, short-chain fatty acid group (SCFA group), perioperative cognitive dysfunction group (PCD group) and perioperative cognitive dysfunction+ short-chain fatty acid group (SCFA+ PCD group), with 8 rats in each group. The perioperative cognitive dysfunction model was established by sevoflurane anesthesia plus internal fixation of tibial fractures. Rats in SCFA group and SCFA+ PCD group freely drank water added with SCFA for 28 days. On the 29th day, rats in SCFA+ FCD group underwent tibial fracture internal fixation surgery. Morris water maze test was performed on the 7th day after surgery to evaluate the cognitive function of rats. The Nissl bodies of hippocampus were observed by Nissl's staining. The hippocampus tissue was collected to analyze the expressions of interleukin-1β (IL-1β), interleukin-6 (IL-6), p38 MAPK, phosphorylated p38 MAPK, NF-κB p65 and phosphorylated NF-κB p65 by Western blot.The SPSS 27.0 software was used for statistical analysis. One-way ANOVA was used for comparison among multiple groups, and LSD- t test was used for further pairwise comparison. Results:(1) The results of Morris water maze test showed that the times of crossing the original platform, the escape latency and the residence time in the original platform quadrant were statistically significant among the four groups on the 7th day after surgery ( F=13.80, 47.80, 6.46, all P<0.05). The escape latencies of the SCFA+ PCD group and PCD group were both longer than that in the control group (both P<0.05). The times of crossing the original platform in SCFA+ PCD group and PCD group were less than that of control group (both P<0.05). The residence time in the original platform quadrant in SCFA+ PCD group and PCD group was shorter than that of control group (both P<0.05).Compared with PCD group, the escape latency was shorter, the times of crossing the original platform were more and the residence time in the original platform quadrant was longer in SCFA+ PCD group (all P<0.05). (2) The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were statistically significant among the four groups ( F=184.28, 139.27, 19.40, 58.47, all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were higher in SCFA+ PCD group (0.49±0.10, 0.60±0.05, 0.489±0.012, 0.435±0.005) and PCD group (0.85±0.05, 1.12±0.08, 0.519±0.028, 0.473±0.008) than those in control group (0.13±0.02, 0.42±0.10, 0.437±0.010, 0.362±0.013)(all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were lower in SCFA+ PCD group than PCD group (all P<0.05). (3) The average gray value of Nissl bodies was statistically significant different among the four groups ( F=14.65, P<0.05). The average gray value of Nissl bodies was lower in SCFA+ PCD group (193.2±8.1) and PCD group (160.5±14.1) than that of control group (221.2±14.8) (both P<0.05). The average gray value of Nissl bodies was higher in SCFA+ PCD group than that in PCD group( P<0.05). Conclusion:Short-chain fatty acid attenuates cognitive dysfunction, which may be related with inhibiting p38 MAPK/NF-κB p65 pathway and reducing the neuroinflammation.
6.Effect of short-chain fatty acid on perioperative cognitive dysfunction in aged rats through p38 MAPK/NF-κB p65 pathway
Xiang LIU ; Xiaona TAN ; Yaozong YU ; Junfang NIU ; Qiujun WANG ; Lei SHI
Chinese Journal of Behavioral Medicine and Brain Science 2025;34(1):9-15
Objective:To evaluate the effect of short-chain fatty acid(SCFA) on perioperative cognitive dysfunction in aged rats through mitogen-activated protein kinase p38(p38 MAPK)/nuclear factor-κB p65(NF-κB p65) pathway.Methods:According to random number table method, 32 healthy SPF-grade male SD rats, aged 16 months and weighing 520~620 g, were divided into control group, short-chain fatty acid group (SCFA group), perioperative cognitive dysfunction group (PCD group) and perioperative cognitive dysfunction+ short-chain fatty acid group (SCFA+ PCD group), with 8 rats in each group. The perioperative cognitive dysfunction model was established by sevoflurane anesthesia plus internal fixation of tibial fractures. Rats in SCFA group and SCFA+ PCD group freely drank water added with SCFA for 28 days. On the 29th day, rats in SCFA+ FCD group underwent tibial fracture internal fixation surgery. Morris water maze test was performed on the 7th day after surgery to evaluate the cognitive function of rats. The Nissl bodies of hippocampus were observed by Nissl's staining. The hippocampus tissue was collected to analyze the expressions of interleukin-1β (IL-1β), interleukin-6 (IL-6), p38 MAPK, phosphorylated p38 MAPK, NF-κB p65 and phosphorylated NF-κB p65 by Western blot.The SPSS 27.0 software was used for statistical analysis. One-way ANOVA was used for comparison among multiple groups, and LSD- t test was used for further pairwise comparison. Results:(1) The results of Morris water maze test showed that the times of crossing the original platform, the escape latency and the residence time in the original platform quadrant were statistically significant among the four groups on the 7th day after surgery ( F=13.80, 47.80, 6.46, all P<0.05). The escape latencies of the SCFA+ PCD group and PCD group were both longer than that in the control group (both P<0.05). The times of crossing the original platform in SCFA+ PCD group and PCD group were less than that of control group (both P<0.05). The residence time in the original platform quadrant in SCFA+ PCD group and PCD group was shorter than that of control group (both P<0.05).Compared with PCD group, the escape latency was shorter, the times of crossing the original platform were more and the residence time in the original platform quadrant was longer in SCFA+ PCD group (all P<0.05). (2) The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were statistically significant among the four groups ( F=184.28, 139.27, 19.40, 58.47, all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were higher in SCFA+ PCD group (0.49±0.10, 0.60±0.05, 0.489±0.012, 0.435±0.005) and PCD group (0.85±0.05, 1.12±0.08, 0.519±0.028, 0.473±0.008) than those in control group (0.13±0.02, 0.42±0.10, 0.437±0.010, 0.362±0.013)(all P<0.05). The expression levels of IL-1β, IL-6, phosphorylated p38 MAPK and phosphorylated NF-κB p65 were lower in SCFA+ PCD group than PCD group (all P<0.05). (3) The average gray value of Nissl bodies was statistically significant different among the four groups ( F=14.65, P<0.05). The average gray value of Nissl bodies was lower in SCFA+ PCD group (193.2±8.1) and PCD group (160.5±14.1) than that of control group (221.2±14.8) (both P<0.05). The average gray value of Nissl bodies was higher in SCFA+ PCD group than that in PCD group( P<0.05). Conclusion:Short-chain fatty acid attenuates cognitive dysfunction, which may be related with inhibiting p38 MAPK/NF-κB p65 pathway and reducing the neuroinflammation.
7.Effects of epifriedelanol on gene expression of P-glycoprotein in human colorectal adenocarcinoma cell line LS174T
Jie JIANG ; Xiao-li ZHANG ; Shi-jia XIANG ; Li-hua YAO ; Guo-ping ZHONG ; Min HUANG ; Yu-hua LI
The Chinese Journal of Clinical Pharmacology 2025;41(1):50-54
Objective To investigate the effect of epifriedelanol(Epi)on gene expression of P-glycoprotein(P-gp)in human colorectal adenocarcinoma cell line LS174T and its mechanism.Methods LS174T cells were divided into control group and experimental-L,-M,-H groups.Experimental-L,-M,-H groups were treated with 5,10,20 μmol·L-1 Epi,respectively.Control group was treated with 0.1%dimethyl sulfoxide.Polymerase chain reaction was used to detect the mRNA expression level of P-gp.Theeffect of Epi on multidrug resistance protein 1(MDR1/P-gp)luciferase activity was investigated by pregnane X receptor(PXR)-MDR1/P-gp dual luciferase reporter gene assay.In addition,Western Blot was used to detect the protein expression level of P-gp and the nuclear factor-κB(NF-κB)pathway related proteins.Results The relative expression levels of P-gp mRNA in experimental-M,-H groups and control group were 52.24±5.19,23.00±3.52 and 100.00±9.00;the relative expression levels of P-gp protein were 86.37±9.96,74.85±15.92 and 100.00±12.91;the relative activities P-gp luciferase were 230.19±41.32,203.10±52.84 and 279.67±19.20;the relative expression levels of p65(RelA/p65)in nucleus were 132.36±23.93,145.96±25.15 and 100.00±10.88;the relative expression levels of phosphorylation NF-κB inhibits protein kinase α/β(p-IKKα/β)in cytoplasm were 184.00±54.82,290.10±49.59 and 100.00±15.34;the relative expression levels of phosphorylated NF-κB inhibitory protein α(p-IκBα)in cytoplasm were 125.73±18.77,133.69±20.25 and 100.00±8.12;the relative expression levels of IκBα in cytoplasm were 78.36±14.83,70.44±14.57 and 100.00±22.82,respectively.The above indexes of experimental-M and experimental-H groups were compared with control group,and the differences were statistically significant(P<0.05,P<0.01,P<0.001).Conclusion Epi can down-regulate the gene expression of P-gp in human colorectal adenocarcinoma cell line LS174T,and the mechanism may be related to activation of NF-κB and suppression of PXR.
8.Analysis of 2033 cases of acute chemical poisoning in a single center from 2016 to 2023
Shizhao XIANG ; Linna LUO ; Lin SHI ; Yu DU
Chinese Journal of Industrial Hygiene and Occupational Diseases 2025;43(9):698-702
Objective:To analyze the characteristics of acute chemical poisoning cases and provide data support for establishing a regional network poisoning early warning and surveillance platform.Methods:In July 2023, patients with acute chemical poisoning who visited the Emergency Department, West China School of Public Health, and West China Fourth Hospital, Sichuan University from May 2016 to May 2023 were selected as the research subjects. Their characteristics such as gender, age, types of poisons, seasonal distribution, and the change trend of the number of poisoned people were analyzed. The annual trend of poisoning population was analyzed by linear regression.Results:There were a total of 2033 patients with acute chemical poisoning, among whom 32 were children (accounting for 1.57%). The gender was mainly female (1146 cases, accounting for 56.37%). The age ranged from 4 to 86 (34.60±10.45) years old. The top three poisonings in terms of acute chemical poisoning were carbon monoxide poisoning with 889 cases (accounting for 43.73%), diquat poisoning with 193 cases (accounting for 9.49%), and paraquat poisoning with 168 cases (accounting for 8.26%). Sedative-hypnotic drug poisoning was mainly in spring (65 cases, accounting for 43.62%), paraquat (65 cases, accounting for 38.69%) and diquat (68 cases, accounting for 35.23%) poisoning was mainly in summer, and carbon monoxide poisoning was mainly in winter (452 cases, accounting for 50.84%). The number of poisoning cases showed a significant increasing trend over the past seven years ( t=6.97, P<0.001). The detection rate of carbon monoxide poisoning was 95.61% (850/889), the detection rate of diquat poisoning was 28.50% (55/193), and the detection rate of paraquat poisoning was 14.88% (25/168) . Conclusion:The poisons of acute chemical poisoning are mainly carbon monoxide, diquat and paraquat. It is necessary to strengthen the publicity and education related to chemical poisoning, the supervision of poisons, and the construction of regional network poisoning early warning and surveillance platforms.
9.Analysis on the incidence trend of liver cancer in Taizhou, Jiangsu Province, 2012-2020
Haiyan LU ; Xiaolan ZHAO ; Tingting SHI ; Luojia DAI ; Dekun ZHANG ; Yuxue YANG ; Xin HUANG ; Tiejun ZHANG ; Shunzhang YU ; Xiang ZHANG
Chinese Journal of Oncology 2025;47(9):867-871
Objective:To analyze the changes in the incidence trend of liver cancer in Taizhou of Jiangsu Province, from 2012 to 2020 and provide reference for tumor prevention and control and management.Methods:Liver cancer incidence data from 2012 to 2020 were extracted from the Taizhou Center for Disease Control and Prevention's tumor registry system. Demographic data were used to calculate the crude incidence rate, age-standardized incidence rate (ASIR), Chinese age-standardized incidence rate (CASIR; based on China's 2010 standard population), and world age-standardized incidence rate (WASIR; based on Segi's world standard population). The Joinpoint regression model was applied to identify inflection points in liver cancer incidence trends during 2012-2020, and annual percentage change (APC) with average annual percentage change (AAPC) were calculated.Results:In 2020, the crude incidence ratio (CIR) of liver cancer in Taizhou was 34.6 per 100 000, with CASIR and WASIR at 19.6 per 100 000 and 14.9 per 100 000, respectively. From 2012 to 2020, the male-to-female ratio of new liver cancer cases was 2.94∶1 (10 455 males vs. 3 559 females), with male incidence consistently higher than female. Overall liver cancer incidence in Taizhou initially increased and then decreased after 2017 (2012-2017: APC=6.4%, P=0.014; 2017-2020: APC=-9.5%, P=0.035), peaking at a CASIR of 26.2 per 100 000 in 2017. The trend in male incidence mirrored the overall pattern, rising before 2017 and declining thereafter (2012-2017: APC=6.2%, P=0.005; 2017-2020: APC=-9.0%, P=0.016). Female incidence remained relatively stable (2012-2016: APC=11.0%, P=0.054; 2016-2020: APC=-6.5%, P=0.130). Conclusions:Liver cancer incidence in Taizhou increased before 2017 and declined thereafter, with 2017 as the turning point. Amid population aging, liver cancer remains a persistent public health challenge requiring sustained attention.
10.The mediating effect of electrocardiographic indicators in the association between exposure to fine particulate matter and its element constituents and blood pressure
Yu WANG ; Wenwen ZHANG ; Qian LIU ; Huiting LING ; Changzhen XIANG ; Yiqi QIU ; Chen CHEN ; Jiaonan WANG ; Jianlong FANG ; Xiaoming SHI
Chinese Journal of Preventive Medicine 2025;59(5):621-627
Objective:To evaluate the mediating effect of electrocardiographic (ECG) indicators in the association between short-term exposure to fine particulate matter (PM 2.5) and blood pressure and to explore the key PM 2.5 element constituents that produce the mediating effect. Methods:Based on a cross-sectional survey across 10 cities in the Beijing-Tianjin-Hebei region and surrounding areas, PM 2.5 and its element constituents were collected from the nearest air monitoring superstation. Blood pressure and ECG indicators of participants were obtained through physical examinations. A multivariate linear regression was used to evaluate the effect of short-term exposures to PM 2.5 on blood pressure. A mediation analysis was used to identify the mediating effect of ECG indicators in the association between exposure to PM 2.5 and its element constituents and blood pressure. Results:The age of the 1 793 participants was (65.1±13.3) years, and 885 (49.4%) were males. During the study period, the daily mean concentration of PM 2.5 was (70±45) μg/m 3, and the systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and pulse pressure (PP) were (139±20), (82±11), (101±13), and (57±17) mmHg (1 mmHg=0.133 kPa), respectively. The results of the multivariate linear regression showed that for every 10 μg/m 3 increase in PM 2.5 on the same day (lag 0), DBP increased by 0.15 (95% CI: 0.02-0.28) mmHg, and PP decreased 0.18 (95% CI: 0.36-0.01) mmHg. The exposure to 14 elemental constituents, such as Ga, Co and Se, was associated with an increase in DBP, while the exposure to 17 elemental constituents, such as Cs, Se and Ag, was associated with a decrease in PP. At lag 0, the PM 2.5-induced increase in DBP was mediated by the QRS interval (mediation percentage of 18.98%), and the PM 2.5-induced decrease in PP was mediated by the QT interval (mediation percentage of -6.31%). The exposure to K, Br, Pb, Zn, Ca, Co, Pd, Cu, and As constituents was associated with increases in DBP mediated by prolonged QRS interval. The exposure to Pb, Zn, K, and As constituents was associated with decreases in PP mediated by prolonged QRS interval. Conclusion:ECG indicators such as QRS interval may mediate the association between short-term exposure to PM 2.5 and its element constituents and blood pressure.

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