1.Acupuncture as A Potential Therapeutic Approach for Tourette Syndrome: Modulation of Neurotransmitter Levels and Gut Microbiota.
Bing-Xin WU ; Jun-Ye MA ; Xi-Chang HUANG ; Xue-Song LIANG ; Bai-le NING ; Qian WU ; Shan-Ze WANG ; Jun-He ZHOU ; Wen-Bin FU
Chinese journal of integrative medicine 2025;31(8):735-742
OBJECTIVE:
To investigate the effects of acupuncture on the neurotransmitter levels and gut microbiota in a mouse model of Tourette syndrome (TS).
METHODS:
Thirty-six male C57/BL6 mice were randomly divided into 4 groups using a random number table method: 3,3'-iminodipropionitrile (IDPN) group, control group, acupuncture group, and tiapride group, with 9 mice in each group. In the IDPN group, acupuncture group, and tiapride group, mice received daily intraperitoneal injections of IDPN (300 mg/kg body weight) for 7 consecutive days to induce stereotyped behaviors. Subsequently, in the acupuncture intervention group, standardized acupuncture treatment was administered for 14 consecutive days to IDPN-induced TS model mice. The selected acupoints included Baihui (DU 20), Yintang (DU 29), Waiguan (SJ 5), and Zulinqi (GB 41). In the tiapride group, mice were administered tiapride (50 mg/kg body weight) via oral gavage daily for 14 consecutive days. The control group, IDPN group, and acupuncture group received the same volume of saline orally for 14 consecutive days. Stereotypic behaviors were quantified through behavioral assessments. Neurotransmitter levels, including dopamine (DA), glutamate (Glu), and aspartate (ASP) in striatal tissue were measured using enzyme-linked immunosorbent assay. Dopamine transporter (DAT) expression levels were additionally quantified through quantitative polymerase chain reaction (qPCR). Gut microbial composition was analyzed through 16S ribosomal RNA gene sequencing, while metabolic profiling was conducted using liquid chromatography-mass spectrometry (LC-MS).
RESULTS:
Acupuncture administration significantly attenuated stereotypic behaviors, concurrently reducing striatal levels of DA, Glu and ASP concentrations while upregulating DAT expression compared with untreated TS controls (P<0.05 or P<0.01). Comparative analysis identified significant differences in Muribaculaceae (P=0.001), Oscillospiraceae (P=0.049), Desulfovibrionaceae (P=0.001), and Marinifilaceae (P=0.014) following acupuncture intervention. Metabolomic profiling revealed alterations in 7 metabolites and 18 metabolic pathways when compared to the TS mice, which involved various amino acid metabolisms associated with DA, Glu, and ASP.
CONCLUSIONS
Acupuncture demonstrates significant modulatory effects on both central neurotransmitter systems and gut microbial ecology, thereby highlighting its dual therapeutic potential for TS management through gut-brain axis regulation.
Animals
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Tourette Syndrome/metabolism*
;
Gastrointestinal Microbiome
;
Neurotransmitter Agents/metabolism*
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Acupuncture Therapy
;
Male
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Mice, Inbred C57BL
;
Mice
2.Expression and characterization of the TsNas36 protein of Trichinella spiralis
Guangquan SI ; Junpeng SONG ; Qingbo LYU ; Xue BAI ; Yang WANG ; Xiaolei LIU ; Lixi-ao ZHANG
Chinese Journal of Veterinary Science 2025;45(6):1225-1232,1242
Trichinella spiralis zinc metalloproteinase NAS-36 gene(TsNas36)is a member of the zinc metalloproteinase family found in excretory secretory products(ESP)of T.spiralis.In this study,TsNas36 gene was cloned and expressed,and its biological characteristics and temporal and spatial characteristics were identified.These results provide a theoretical and material basis for ex-ploring the biological function of TsNas36 gene.Bioinformatics analysis showed that TsNas36 was 470 amino acids(AA)in length with a molecular weight of about 54.69 kDa,no transmembrane region,and contained a signal peptide(1-20 AA),an Astacins domain(116-320 AA)and a CUB domain(355-470 AA).There were five active site residues located at amino acids 216(His),217(Glu),220(His),226(His)and 275(Tyr).The expression plasmid pET-28a(+)/TsNas36 was constructed and induced to express in E.coli BL21(DE3)to obtain the recombinant protein rTs-Nas36.The recombinant protein was used to immunize rabbits to obtain anti-rTsNas36 polyclonal antibody serum.Indirect ELISA results showed that the antibody titer reached 1∶105.qRT-PCR and Western blot results showed that the transcription levels of TsNas36 were significantly higher in newborn larvae(NBL)than in adult worm(AW)and muscle larva(ML)stages.Immunofluo-rescence results showed that TsNas36 was only localized in the epidermis of NBL.In summary,this study characterized the biological characteristics of the TsNas36 gene and found that this gene is highly period-specific and may be involved in the unique developmental process of NBL.
3.Effect of urushiol primer on remineralization and adhesion properties of demineralized dentin
Tingting BAI ; Fei WEI ; Guangdi SUN ; Xue CHEN ; Song ZHU
Journal of Jilin University(Medicine Edition) 2025;51(1):133-142
Objective:To explore the promotion effect on remineralization of demineralized dentin of urushiol primer applicated in acid-etch-rinse adhesives,and to clarify its impact on the longevity of dentin adhesion.Methods:Ninety-six freshly extracted,caries-free third molars were selected to prepare the dentin specimens.Following acid etching with 37%phosphoric acid gel,the specimens were randomly divided into blank control group,0.3%,0.7%,1.0%,and 1.5%urushiol groups,and positive control group(acetone solvent).The treated samples were placed in modified simulated body fluids for remineralization for 14 and 28 d.Attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR)was used to detect the relative mineralization mass of minerals in the dentinal tubules in various groups,and X-ray Diffractometery and Energy Dispersive spectrometer were used to analyze the dentin surface material compositions in various groups.Scanning electron microscope(SEM)was used to observe the surface morphology of the specimens in various groups,Vickers hardness tester was used to measure the microhardness of the dentin surface in various groups,and microtensile strength(μTBS)was used to examine the effect of the bond strengthes in various groups.Results:Compared with blank control group,the conversion rate of adhesive double bonds by primer in positive control group was decreased,but the difference was not significant(P>0.05);but the conversion rates of adhesive double bonds by primer in 0.3%,0.7%,1.0%,and 1.5%urushiol groups were increased(P<0.05).The SEM results revealed that at 14 and 28 d,compared with bland control group,a minimal membranous deposit in dentinal tubules was seen in positive control group,minimal mineralization displayed in 0.3%urushiol group,significant deposition of loose mineral particles with blocking the tubule orifices was found in 0.7%urushiol group,noticeable mineral precipitates exhibited in 1.0%urushiol group,and relatively empty dentinal tubules were seen in 1.5%urushiol group.The microhardness results showed that at 14 d after remineralization,compared with blank control group,the microhardness in positive control group showed no significant improvement(P>0.05),while the differences in 0.3%,0.7%,1.0%and 1.5%urushiol groups were statistically significant(P<0.05);at 14 d after remineralization compared with positive control group,the microhardness of dertin in 0.7%and 1.0%urushiol groups were increased(P<0.05);at 28 d after remineralization,compared with blank control and postive control groups,the microhardness in urushiol groups were significantly increased(P<0.05),espectially in 0.7%to 1.5%urushiol groups(P<0.05).In the μTBS test,at 14 d after remineralization,compared with postive control group,theμTBS in 0.3%,0.7%,1.0%and 1.5%urushiol groups were increased(P<0.05);at 28 d after remineralization,the μTBS in blank control group was the lowest;compared with blank control group,there was no significant difference in the μTBS in postive control group(P>0.05);compared with positive control group,the μTBS in 0.3%,0.7%,1.0%,and 1.5%urushiol groups were increased(P<0.05),espectially in 0.7%,1.0,and 1.5%urushiol groups(P<0.05).Conclusion:Natural-derived urushiol,as a novel primer,can pretreat the demineralized dentin substrates,and facilitate collagen cross-linking within the dentin matrix;moreover,it leverages the phenolic hydroxyl groups within its structure to attact calcium and phosphate ions,envelope dentin collagen fibers to promote remineralization,in order to enhance the strength of the resin-dentin bonding interface.
4.Effects of high-fat diet intake on pharmacokinetics of rabeprazole sodium enteric-coated tablets in healthy Chinese subjects
Cai-hui GUO ; Yu-fang XU ; Cong-yang DING ; Guang-tao HAO ; Hao-jing SONG ; Xue SUN ; Zhan-jun DONG ; Wan-jun BAI
The Chinese Journal of Clinical Pharmacology 2025;41(2):225-229
Objective To evaluate the effects of fasting and high-fat diet on the pharmacokinetics of rabeprazole sodium enteric-coated tablets in healthy Chinese subjects.Methods A single-center,randomized,open,two-agent,two-sequence,four-cycle,fully repeated crossover,single-dose trial design was used in this study,healthy subjects were assigned to receive single dose of rabeprazole sodium enteric-coated tablets 0.1 g in either fasting or high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of rabeprazole sodium enteric-coated in plasma were determined by liquid chromatography-tandem mass spectrometry(LC-MS/MS),the model method of the non-compartmental was used to calculate the pharmacokinetic parameters by Phoenix WinNonlin 8.2.Results The main pharmacokinetic parameters of rabeprazole sodium enteric-coated tablets in fasting state and high-fat diet state were as follows:Cmax were(339.63±156.47)and(318.86±132.13)ng·mL-1;t1/2 were(2.34±0.68)and(3.60±2.40)h;AUC0_t were(556.62±251.65)and(528.50±201.78)ng·mL-1·h;AUC0-∞ were(563.39±255.69)and(535.15±203.24)ng·mL-1·h;tmax were 3.65 and 6.99 h.After high-fat diet,the Cmax and AUC of rapeprazole sodium after high-fat and high-calorie diet decreased,Cmax decreased by 6.12%,AUC0-t decreased by 5.05%,AUC0-∞ decreased by 5.01%,andtmaxwas delayed by about 3.34 h.Cmax,AUC0-t and AUC0-∞ 90%confidence interval were 73.13%-115.10%,83.22%-112.28%and 83.40%-112.13%,respectively.Neither was between 85.00%-125.00%.Conclusion High-fat diet affects the absorption rate and degree of rabeprazole sodium enteric-coated,so it is suitable to be administered on an empty stomach.
5.Effects of myocardial extracellular matrix remodeling on connexin 43 and its Ser368 phosphorylation and electrical conduction
Yuting SONG ; Chunlei WEN ; Yi LI ; Xue BAI ; Hong GAO ; Tingju HU ; Zijun WANG ; Xu YAN
Chinese Journal of Tissue Engineering Research 2025;29(29):6212-6218
BACKGROUND:Our previous studies found that decreased expression of connexin 43 and its Ser368 phosphorylation after myocardial hypothermic ischemia-reperfusion was closely associated with decreased cardiac conduction velocity and reperfusion arrhythmia.OBJECTIVE:To observe the effect of changes in membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2 and collagen type Ⅳ on the expression of connexin 43 and its Ser368 phosphorylation and electrical conduction in the myocardial extracellular matrix after hypothermic ischemia-reperfusion.METHODS:Sixteen Langendorff extracorporeal cardiac perfusion models were successfully established from SD rats and randomly divided into a control group(n=8)and a hypothermic ischemia-reperfusion group(n=8).The control group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes and then continued to be perfused with 37 ℃ Krebs-Henseleit solution for 90 minutes.The hypothermic ischemia-reperfusion group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes,and then the heart was arrested for 60 minutes by injection of 4 ℃ Thomas solution.During the cardiac arrest,the periphery was protected by 4 ℃ Krebs-Henseleit solution.Half-volume 4 ℃ Thomas solution was reperfused 30 minutes after the arrest.After stopping the arrest,the heart was reperfused with 37 ℃ Krebs-Henseleit solution for 30 minutes.The occurrence of arrhythmias,rebeating time,and the duration of arrhythmias were recorded from the immediate time point to the end of the reperfusion period.Conduction velocity,absolute inhomogeneity,and inhomogeneity index were measured using the Mapping Lab multi-channel electrophysiological mapping system at the time of balanced perfusion for 15 minutes(T1),reperfusion for 15 minutes/continuous perfusion for 90 minutes(T2),and reperfusion for 30 minutes/continuous perfusion for 105 minutes(T3).The relative expression levels of membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2,collagen type Ⅳ,connexin 43,and its Ser368 phosphorylation in ventricular tissue were detected by western blot assay.RESULTS AND CONCLUSION:(1)No arrhythmia occurred in the control group.There were six cases of arrhythmia in the hypothermic ischemia-reperfusion group during reperfusion.Rebeating time and duration of arrhythmias were(25.38+12.02)and(158.67±67.68)seconds,respectively.(2)The conduction sochronal diagrams at T1,T2,and T3 in the control group were uniform and regular in direction,and the conduction velocity at T2 and T3 was not different from that at T1(P>0.05).The conduction isochronal diagrams at T2 and T3 in the hypothermic ischemia-reperfusion group were uneven and irregular in direction,and the conduction velocity was slower than that at T1(P<0.01).The conduction velocity at T2 and T3 in the hypothermic ischemia-reperfusion group was slower than that in the control group(P<0.01).Conduction dispersion was greater in the hypothermic ischemia-reperfusion group than that in the control group at T2 and T3(P<0.05).(3)Compared with the control group,the protein expressions of membrane-type matrix metalloproteinase 2 and matrix metalloproteinase 2 in the hypothermic ischemia-reperfusion group were increased(P<0.05 or P<0.01),and the protein expression levels of type Ⅳ collagen,connexin 43 and its Ser368 phosphorylation were decreased(P<0.05 or P<0.01).(4)The results indicate that after hypothermic ischemia-reperfusion,myocardial extracellular matrix remodeling may mediate the downregulation of myocardial connexin 43 and its Ser368 phosphorylation,slowed conduction velocity and increased conduction dispersion,thereby increasing the risk of arrhythmia.
6.A study on the correlation between regional hemodynamics and plaque morphology of middle cerebral artery in atherosclerotic stenosis using four-dimensional flow MRI
Yuanbin ZHAO ; Xiaoyan BAI ; Chao ZHANG ; Xue ZHANG ; Tong CHEN ; Xun PEI ; Yuehua PU ; Ligang SONG ; Binbin SUI
Chinese Journal of Radiology 2025;59(3):261-268
Objective:To explore the hemodynamic characteristics of the middle cerebral artery (MCA) in atherosclerotic stenosis using four-dimensional flow (4D Flow) MRI, and combining high-resolution magnetic resonance vessel wall imaging (HR VW-MRI) to analyze the relationship between hemodynamics and the degree of stenosis, as well as the morphological characteristics of plaques.Methods:The study was a cross-sectional study. A total of 24 patients with middle cerebral artery(MCA) M1 atherosclerotic stenosis and 10 age and sex matched healthy controls (HC group) were prospectively recruited from September 2018 to March 2021 at Beijing Tiantan Hospital, Capital Medical University. All subjects underwent MRI examination. The hemodynamic of MCA were collected by 4D Flow MRI, and the hemodynamic parameters of proximal and distal MCA stenosis were calculated by blood flow post-processing software, including average blood flow rate (FR avg), average blood flow velocity (V avg), peak blood flow velocity (V pk), time average wall shear stress (TAWSS), minimum wall shear stress (WSS min) and oscillatory shear index (OSI). The differences in hemodynamic parameters among the proximal and distal ends of MCA stenosis and the HC group were compared using one-way ANOVA or Kruskal-Wallis H test. The stenosis rate and characteristics of MCA plaque were analyzed by HR VW-MRI, including remodeling index (RI), normalized wall index (NWI) and plaque length. Pearson or Spearman correlation analysis was used to explore the correlation between stenosis rate and hemodynamic parameters. Taking the stenosis rate as the control variable, partial correlation analysis was used to explore the correlation between plaque morphological characteristics and hemodynamic parameters. Results:There were statistically significant differences in FR avg, V avg, V pk, TAWSS, OSI, WSS min among the proximal and distal stenosis of MCA and HC groups ( P<0.05). The proximal end of the MCA stenosis had significantly higher FR avg, V avg, TAWSS and WSS min than those of the distal end of the stenosis ( P<0.01). The FR avg, V avg, V pk, TAWSS, and WSS min in the distal end of MCA stenosis were lower than those in the HC group, while the OSI was higher than that in the HC group ( P<0.01). The correlation analysis results showed that the MCA proximal V pk ( r=-0.425, P=0.027) and distal V pk ( r=-0.538, P=0.004) were negatively correlated with the diameter stenosis rate. When the stenosis rate was taken as the control factor, in the MCA proximal stenosis, V avg ( r=0.553, P=0.003), TAWSS ( r=0.543, P=0.004) and WSS min ( r=0.547, P=0.004) were positively correlated with RI, proximal OSI was negatively correlated with RI ( r=-0.492, P=0.011), and was positively correlated with the plaque length ( r=0.437, P=0.026). At the distal end of the stenosis, V pk was negatively correlated with NWI ( r=-0.556, P=0.003), OSI was negatively correlated with RI ( r=-0.511, P=0.008), NWI ( r=-0.390, P=0.049). TAWSS was positively correlated with RI ( r=0.393, P=0.047). Conclusions:The 4D Flow MRI demonstrates characteristic hemodynamic changes in the proximal and distal ends of the stenotic MCA. The local hemodynamic characteristics of the stenotic MCA are correlated with plaque morphological parameters, including lumen stenosis, plaque load, and RI. It suggests an interaction between the occurrence and development of MCA plaque and local hemodynamic changes.
7.Analysis of Characteristics in Chinese-Registered Clinical Trials for Weight-Loss Medications
Bo QIU ; Runxuan DU ; Haotian YANG ; Haojing SONG ; Xue SUN ; Congyang DING ; Wanjun BAI ; Zhanjun DONG
Herald of Medicine 2025;44(9):1516-1520
Objective To investigate the status and developmental trends of clinical trials for weight control drugs in China,and to provide data support for sponsors,researchers,and regulatory authorities.Methods The drug clinical trial registration and information platform of the National Medical Products Administration was utilized to search for registered clinical trials of weight control drugs from November 2012 to June 2024.The search employed"overweight","obesity",and"weight loss"as keywords.The information collected included project registration time,drug name,dosage form,drug classification,indications,trial staging,study progress,design type,lead unit,and sponsor.Microsoft Office Excel software was employed for data entry,organization,and extraction.Results A total of 95 registered clinical trials of weight control drugs were identified,comprising 40 domestic multicenter trials,47 domestic single-center trials,and 8 international multicenter trials.Regarding trial phasing,46(48.4%)were phase Ⅰ clinical trials,17(17.9%)were phase Ⅱ clinical trials,19(20.0%)were phase Ⅲ clinical trials,and 13(13.7%)were bioequivalence trials.The drug categorization encompassed 22 chemical drugs,20 biological products,and 1 traditional Chinese medicine/natural drug.Concerning drug dosage forms,there were 32 items of injectable dosage forms,8 items of tablets,2 items of capsules,and 1 item of chewable tablets.Conclusions Registered clinical trials for weight-loss medications in China are predominantly concentrated in regions with developed medical resources.Injectable biologics constitute most test drugs,with most drugs in the early stages of research and development.The examination of the safety and efficacy of these drugs remains to be substantiated,and it is anticipated that a considerable period will elapse before their approval and market introduction.
8.Expression and characterization of the TsNas36 protein of Trichinella spiralis
Guangquan SI ; Junpeng SONG ; Qingbo LYU ; Xue BAI ; Yang WANG ; Xiaolei LIU ; Lixi-ao ZHANG
Chinese Journal of Veterinary Science 2025;45(6):1225-1232,1242
Trichinella spiralis zinc metalloproteinase NAS-36 gene(TsNas36)is a member of the zinc metalloproteinase family found in excretory secretory products(ESP)of T.spiralis.In this study,TsNas36 gene was cloned and expressed,and its biological characteristics and temporal and spatial characteristics were identified.These results provide a theoretical and material basis for ex-ploring the biological function of TsNas36 gene.Bioinformatics analysis showed that TsNas36 was 470 amino acids(AA)in length with a molecular weight of about 54.69 kDa,no transmembrane region,and contained a signal peptide(1-20 AA),an Astacins domain(116-320 AA)and a CUB domain(355-470 AA).There were five active site residues located at amino acids 216(His),217(Glu),220(His),226(His)and 275(Tyr).The expression plasmid pET-28a(+)/TsNas36 was constructed and induced to express in E.coli BL21(DE3)to obtain the recombinant protein rTs-Nas36.The recombinant protein was used to immunize rabbits to obtain anti-rTsNas36 polyclonal antibody serum.Indirect ELISA results showed that the antibody titer reached 1∶105.qRT-PCR and Western blot results showed that the transcription levels of TsNas36 were significantly higher in newborn larvae(NBL)than in adult worm(AW)and muscle larva(ML)stages.Immunofluo-rescence results showed that TsNas36 was only localized in the epidermis of NBL.In summary,this study characterized the biological characteristics of the TsNas36 gene and found that this gene is highly period-specific and may be involved in the unique developmental process of NBL.
9.Effects of high-fat diet intake on pharmacokinetics of rabeprazole sodium enteric-coated tablets in healthy Chinese subjects
Cai-hui GUO ; Yu-fang XU ; Cong-yang DING ; Guang-tao HAO ; Hao-jing SONG ; Xue SUN ; Zhan-jun DONG ; Wan-jun BAI
The Chinese Journal of Clinical Pharmacology 2025;41(2):225-229
Objective To evaluate the effects of fasting and high-fat diet on the pharmacokinetics of rabeprazole sodium enteric-coated tablets in healthy Chinese subjects.Methods A single-center,randomized,open,two-agent,two-sequence,four-cycle,fully repeated crossover,single-dose trial design was used in this study,healthy subjects were assigned to receive single dose of rabeprazole sodium enteric-coated tablets 0.1 g in either fasting or high-fat diet state,and blood samples were taken at different time points,respectively.The concentrations of rabeprazole sodium enteric-coated in plasma were determined by liquid chromatography-tandem mass spectrometry(LC-MS/MS),the model method of the non-compartmental was used to calculate the pharmacokinetic parameters by Phoenix WinNonlin 8.2.Results The main pharmacokinetic parameters of rabeprazole sodium enteric-coated tablets in fasting state and high-fat diet state were as follows:Cmax were(339.63±156.47)and(318.86±132.13)ng·mL-1;t1/2 were(2.34±0.68)and(3.60±2.40)h;AUC0_t were(556.62±251.65)and(528.50±201.78)ng·mL-1·h;AUC0-∞ were(563.39±255.69)and(535.15±203.24)ng·mL-1·h;tmax were 3.65 and 6.99 h.After high-fat diet,the Cmax and AUC of rapeprazole sodium after high-fat and high-calorie diet decreased,Cmax decreased by 6.12%,AUC0-t decreased by 5.05%,AUC0-∞ decreased by 5.01%,andtmaxwas delayed by about 3.34 h.Cmax,AUC0-t and AUC0-∞ 90%confidence interval were 73.13%-115.10%,83.22%-112.28%and 83.40%-112.13%,respectively.Neither was between 85.00%-125.00%.Conclusion High-fat diet affects the absorption rate and degree of rabeprazole sodium enteric-coated,so it is suitable to be administered on an empty stomach.
10.Effects of myocardial extracellular matrix remodeling on connexin 43 and its Ser368 phosphorylation and electrical conduction
Yuting SONG ; Chunlei WEN ; Yi LI ; Xue BAI ; Hong GAO ; Tingju HU ; Zijun WANG ; Xu YAN
Chinese Journal of Tissue Engineering Research 2025;29(29):6212-6218
BACKGROUND:Our previous studies found that decreased expression of connexin 43 and its Ser368 phosphorylation after myocardial hypothermic ischemia-reperfusion was closely associated with decreased cardiac conduction velocity and reperfusion arrhythmia.OBJECTIVE:To observe the effect of changes in membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2 and collagen type Ⅳ on the expression of connexin 43 and its Ser368 phosphorylation and electrical conduction in the myocardial extracellular matrix after hypothermic ischemia-reperfusion.METHODS:Sixteen Langendorff extracorporeal cardiac perfusion models were successfully established from SD rats and randomly divided into a control group(n=8)and a hypothermic ischemia-reperfusion group(n=8).The control group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes and then continued to be perfused with 37 ℃ Krebs-Henseleit solution for 90 minutes.The hypothermic ischemia-reperfusion group was balanced perfused with 37 ℃ Krebs-Henseleit solution for 15 minutes,and then the heart was arrested for 60 minutes by injection of 4 ℃ Thomas solution.During the cardiac arrest,the periphery was protected by 4 ℃ Krebs-Henseleit solution.Half-volume 4 ℃ Thomas solution was reperfused 30 minutes after the arrest.After stopping the arrest,the heart was reperfused with 37 ℃ Krebs-Henseleit solution for 30 minutes.The occurrence of arrhythmias,rebeating time,and the duration of arrhythmias were recorded from the immediate time point to the end of the reperfusion period.Conduction velocity,absolute inhomogeneity,and inhomogeneity index were measured using the Mapping Lab multi-channel electrophysiological mapping system at the time of balanced perfusion for 15 minutes(T1),reperfusion for 15 minutes/continuous perfusion for 90 minutes(T2),and reperfusion for 30 minutes/continuous perfusion for 105 minutes(T3).The relative expression levels of membrane-type matrix metalloproteinase 2,matrix metalloproteinase 2,collagen type Ⅳ,connexin 43,and its Ser368 phosphorylation in ventricular tissue were detected by western blot assay.RESULTS AND CONCLUSION:(1)No arrhythmia occurred in the control group.There were six cases of arrhythmia in the hypothermic ischemia-reperfusion group during reperfusion.Rebeating time and duration of arrhythmias were(25.38+12.02)and(158.67±67.68)seconds,respectively.(2)The conduction sochronal diagrams at T1,T2,and T3 in the control group were uniform and regular in direction,and the conduction velocity at T2 and T3 was not different from that at T1(P>0.05).The conduction isochronal diagrams at T2 and T3 in the hypothermic ischemia-reperfusion group were uneven and irregular in direction,and the conduction velocity was slower than that at T1(P<0.01).The conduction velocity at T2 and T3 in the hypothermic ischemia-reperfusion group was slower than that in the control group(P<0.01).Conduction dispersion was greater in the hypothermic ischemia-reperfusion group than that in the control group at T2 and T3(P<0.05).(3)Compared with the control group,the protein expressions of membrane-type matrix metalloproteinase 2 and matrix metalloproteinase 2 in the hypothermic ischemia-reperfusion group were increased(P<0.05 or P<0.01),and the protein expression levels of type Ⅳ collagen,connexin 43 and its Ser368 phosphorylation were decreased(P<0.05 or P<0.01).(4)The results indicate that after hypothermic ischemia-reperfusion,myocardial extracellular matrix remodeling may mediate the downregulation of myocardial connexin 43 and its Ser368 phosphorylation,slowed conduction velocity and increased conduction dispersion,thereby increasing the risk of arrhythmia.

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