1.The Potential and Challenges of Temporal Interference Stimulation in Chronic Pain Management
Hao-Qing DUAN ; Yu-Qi GOU ; Ya-Wen LI ; Li HU ; Xue-Jing LÜ
Progress in Biochemistry and Biophysics 2026;53(2):369-387
Chronic pain is a complex condition shaped by long-standing alterations in both physiological and psychological processes. Rather than representing a simple continuation of acute nociceptive signaling, chronic pain is increasingly understood as the outcome of progressive dysregulation within distributed neural systems that govern sensation, affect, motivation, and cognitive control. Neuroimaging and electrophysiological studies indicate that this state is accompanied by extensive plastic changes in deep brain structures and large-scale networks. Beyond well-described central sensitization processes, chronic pain is characterized by disrupted oscillatory rhythms and altered connectivity within large-scale brain networks, including thalamo-cortical circuits and prefrontal-limbic-reward networks. These findings support a conceptual shift from viewing chronic pain as a focal, lesion-driven phenomenon toward recognizing it as a disorder of distributed network pathology. Pharmacological treatments remain central to clinical practice, yet their long-term efficacy is often limited and frequently accompanied by substantial side effects. The ongoing concerns about opioid-related risks and the inadequate therapeutic response in a subset of patients highlight the need for safe, non-pharmacological approaches that can address not only pain but also comorbid disturbances in mood, sleep, and social functioning. Neuromodulation provides a promising path toward mechanism-based and non-pharmacological management of chronic pain by employing physical or chemical stimulation to alter the excitability and synchrony of specific neural populations within central, peripheral, and autonomic systems. While invasive deep brain stimulation demonstrates that targeting deep brain structures can be effective, its clinical application is restricted by surgical risks and cost, highlighting the importance of non-invasive techniques capable of reaching deep targets. Current non-invasive approaches, such as transcranial electric stimulation, are constrained by limited penetration depth and insufficient spatial precision. These limitations hinder reliable engagement of deep regions implicated in pain, including the thalamus and nucleus accumbens, and tend to produce broad, non-specific modulation of cross-network oscillatory activity. Temporal interference (TI) stimulation has emerged as a means of overcoming these obstacles. By delivering interacting high-frequency currents that generate a low-frequency envelope within the head, TI enables focal stimulation of deep targets while minimizing superficial current delivery. Recent multiscale modeling and animal studies indicate that TI exploits the nonlinear rectification properties of neuronal membranes in response to high-frequency carriers, as well as their phase-locked responses to low-frequency envelopes, to generate “peak-focused” electric fields in deep regions under relatively low superficial current loads. Moreover, TI appears to exhibit potential advantages in terms of cell-type selectivity and rhythm-specific engagement, including differential responses across neuronal subtypes and distinct coupling to θ-, β-, and γ-band oscillations. These features suggest a promising avenue for correcting abnormal rhythms and network dynamics that contribute to chronic pain. This review summarizes current knowledge of the neural mechanisms underlying chronic pain and recent advances in TI research. It examines functional disturbances across key pain-related regions and networks, outlines the principles and technical characteristics of TI, and discusses potential deep-brain targets and stimulation strategies relevant to chronic pain. Evidence to date indicates that TI, with its non-invasiveness, tolerability, and capacity for precise deep brain modulation, holds great promise for the management of treatment-resistant chronic pain and may evolve into a new generation of precise and efficient non-pharmacological analgesic strategies.
2.The Potential and Challenges of Temporal Interference Stimulation in Chronic Pain Management
Hao-Qing DUAN ; Yu-Qi GOU ; Ya-Wen LI ; Li HU ; Xue-Jing LÜ
Progress in Biochemistry and Biophysics 2026;53(2):369-387
Chronic pain is a complex condition shaped by long-standing alterations in both physiological and psychological processes. Rather than representing a simple continuation of acute nociceptive signaling, chronic pain is increasingly understood as the outcome of progressive dysregulation within distributed neural systems that govern sensation, affect, motivation, and cognitive control. Neuroimaging and electrophysiological studies indicate that this state is accompanied by extensive plastic changes in deep brain structures and large-scale networks. Beyond well-described central sensitization processes, chronic pain is characterized by disrupted oscillatory rhythms and altered connectivity within large-scale brain networks, including thalamo-cortical circuits and prefrontal-limbic-reward networks. These findings support a conceptual shift from viewing chronic pain as a focal, lesion-driven phenomenon toward recognizing it as a disorder of distributed network pathology. Pharmacological treatments remain central to clinical practice, yet their long-term efficacy is often limited and frequently accompanied by substantial side effects. The ongoing concerns about opioid-related risks and the inadequate therapeutic response in a subset of patients highlight the need for safe, non-pharmacological approaches that can address not only pain but also comorbid disturbances in mood, sleep, and social functioning. Neuromodulation provides a promising path toward mechanism-based and non-pharmacological management of chronic pain by employing physical or chemical stimulation to alter the excitability and synchrony of specific neural populations within central, peripheral, and autonomic systems. While invasive deep brain stimulation demonstrates that targeting deep brain structures can be effective, its clinical application is restricted by surgical risks and cost, highlighting the importance of non-invasive techniques capable of reaching deep targets. Current non-invasive approaches, such as transcranial electric stimulation, are constrained by limited penetration depth and insufficient spatial precision. These limitations hinder reliable engagement of deep regions implicated in pain, including the thalamus and nucleus accumbens, and tend to produce broad, non-specific modulation of cross-network oscillatory activity. Temporal interference (TI) stimulation has emerged as a means of overcoming these obstacles. By delivering interacting high-frequency currents that generate a low-frequency envelope within the head, TI enables focal stimulation of deep targets while minimizing superficial current delivery. Recent multiscale modeling and animal studies indicate that TI exploits the nonlinear rectification properties of neuronal membranes in response to high-frequency carriers, as well as their phase-locked responses to low-frequency envelopes, to generate “peak-focused” electric fields in deep regions under relatively low superficial current loads. Moreover, TI appears to exhibit potential advantages in terms of cell-type selectivity and rhythm-specific engagement, including differential responses across neuronal subtypes and distinct coupling to θ-, β-, and γ-band oscillations. These features suggest a promising avenue for correcting abnormal rhythms and network dynamics that contribute to chronic pain. This review summarizes current knowledge of the neural mechanisms underlying chronic pain and recent advances in TI research. It examines functional disturbances across key pain-related regions and networks, outlines the principles and technical characteristics of TI, and discusses potential deep-brain targets and stimulation strategies relevant to chronic pain. Evidence to date indicates that TI, with its non-invasiveness, tolerability, and capacity for precise deep brain modulation, holds great promise for the management of treatment-resistant chronic pain and may evolve into a new generation of precise and efficient non-pharmacological analgesic strategies.
3.Study on the effects and mechanisms of Lycium ruthenicum Murr. in improving sleep
Ming QIAO ; Yao ZHAO ; Yi ZHU ; Yexia CAO ; Limei WEN ; Yuehong GONG ; Xiang LI ; Juanchen WANG ; Tao WANG ; Jianhua YANG ; Junping HU
China Pharmacy 2026;37(1):24-29
OBJECTIVE To investigate the effects and mechanisms of Lycium ruthenicum Murr. in improving sleep. METHODS Network pharmacology was employed to identify the active components of L. ruthenicum and their associated disease targets, followed by enrichment analysis. A caffeine‑induced zebrafish model of sleep deprivation was established , and the zebrafish were treated with L. ruthenicum Murr. extract (LRME) at concentrations of 0.1, 0.2 and 0.4 mg/mL, respectively; 24 h later, behavioral changes of zebrafish and pathological alterations in brain neurons were subsequently observed. The levels of inflammatory factors [interleukin-6 (IL-6), IL-1β, IL-10, tumor necrosis factor-α (TNF-α)], oxidative stress markers [superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), catalase (CAT)], and neurotransmitters [5- hydroxytryptamine (5-HT), γ-aminobutyric acid (GABA), glutamic acid (Glu), dopamine (DA), and norepinephrine (NE)] were measured. The protein expression levels of protein kinase B1 (AKT1), phosphorylated AKT1 (p-AKT1), epidermal growth factor receptor (EGFR), B-cell lymphoma 2 (Bcl-2), sarcoma proto-oncogene,non-receptor tyrosine kinase (SRC), and heat shock protein 90α family class A member 1 (HSP90AA1) in the zebrafish were also determined. RESULTS A total of 12 active components and 176 intersecting disease targets were identified through network pharmacology analysis. Among these, apigenin, naringenin and others were recognized as core active compounds, while AKT1, EGFR and others served as key targets; EGFR tyrosine kinase inhibitor resistance signaling pathway was identified as the critical pathway. The sleep improvement rates in zebrafish of LRME low-, medium-, and high-dose groups were 54.60%, 69.03% and 77.97%, 开发。E-mail:hjp_yft@163.com respectively, while the inhibition ratios of locomotor distance were 0.57, 0.83 and 0.95, respectively. Compared with the model group, the number of resting counts, resting time and resting distance were significantly increased/extended in LRME medium- and high-dose groups (P<0.05). Neuronal damage in the brain was alleviated. Additionally, the levels of IL-6, IL-1β, TNF-α, MDA, Glu, DA and NE, as well as the protein expression levels of AKT1, p-AKT1, EGFR, SRC and HSP90AA1, were markedly reduced (P<0.05), while the levels of IL-10, SOD, GSH-Px, CAT, 5-HT and GABA, as well as Bcl-2 protein expression, were significantly elevated (P<0.05). CONCLUSIONS L. ruthenicum Murr. demonstrates sleep-improving effects, and its specific mechanism may be related to the regulation of inflammatory responses, oxidative stress, neurotransmitter balance, and the EGFR tyrosine kinase inhibitor resistance signaling pathway.
4.Application of Recombinant Collagen in Biomedicine
Huan HU ; Hong ZHANG ; Jian WANG ; Li-Wen WANG ; Qian LIU ; Ning-Wen CHENG ; Xin-Yue ZHANG ; Yun-Lan LI
Progress in Biochemistry and Biophysics 2025;52(2):395-416
Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.
5.Worksite survey of occupational disease diagnosis
China Occupational Medicine 2025;52(1):1-9
The worksite survey of occupational disease diagnosis is a series of occupational health investigations in the workplace initiated by the occupational disease diagnosis institution or the public health administrative department in order to understand whether there is a causal relationship between the workers' diseases and the workplace in the process of occupational disease diagnosis and verification. The main purpose of the worksite survey is to find out whether there are occupational hazards that cause health damage to workers in the workplace, and to analyze whether there is a causal relationship between the exposure to occupational hazards at the corresponding concentration (intensity) and the diseases suffered by workers. In actual work, it is necessary to determine whether it is necessary to organize worksite survey according to the legal situation and actual work of occupational disease diagnosis. The mainly works of worksite survey includes three aspects: preliminary preparation, survey implementation and survey report writing. It is necessary to pay attention to the key and difficult tasks such as preparation before survey, survey plan and questionnaire, complexity and uncertainty of worksite survey and sampling and detection of occupational hazard factors in workplace. After the worksite survey,it is necessary to write a written occupational disease on-site investigation report to provide objective, reliable and scientific evidence for occupational disease diagnosis.
6.Characterization of hippocampal components of Danzhi Xiaoyao Formula based on HPLC-Q-TOF-MS/MS and network pharmacology and assessment of its therapeutic potential for nervous system diseases.
Wen-Qing HU ; Hui-Yuan GAO ; Li YANG ; Yu-Xin WANG ; Hao-Jie CHENG ; Si-Yu YANG ; Mei-Yu ZHANG ; Jian SUN
China Journal of Chinese Materia Medica 2025;50(14):4053-4062
In this study, the pharmacodynamic components and potential pharmacological functions of Danzhi Xiaoyao Formula in treating nervous system diseases were investigated by hippocampal component characterization and network pharmacology. After rats were administrated with Danzhi Xiaoyao Formula by gavage, high performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry(HPLC-Q-TOF-MS/MS) was employed to explore the components in the hippocampus of rats. Fifty-seven components were identified in the hippocampus of rats by comparing the extract of Danzhi Xiaoyao Formula, herbal components in the hippocampus after administration, and blank samples. KEGG and GO analyses predicted 74 core targets including GSK3B, MAPK1, AKT, IL6. These targets were involved in PI3K/Akt, NF-κB, MAPK, JAK/STAT, Wnt, and other signaling pathways. The results indicated that Danzhi Xiaoyao Formula may ameliorate other nervous system diseases enriched in DO, such as neurodegenerative diseases, cerebrovascular diseases, and mental and emotional disorders by mediating target pathways, inhibiting inflammation, reducing neuronal damage, and alleviating hippocampal atrophy. The relevant activities exhibited by this formula in nervous system diseases such as Alzheimer's disease, Parkinson's disease, and diabetic neuropathy have extremely high development value and are worthy of further in-depth research. This study provides a theoretical basis and practical guidance for expanding the application of Danzhi Xiaoyao Formula in the treatment of nervous system diseases.
Drugs, Chinese Herbal/administration & dosage*
;
Animals
;
Rats
;
Hippocampus/metabolism*
;
Network Pharmacology
;
Chromatography, High Pressure Liquid
;
Tandem Mass Spectrometry
;
Rats, Sprague-Dawley
;
Male
;
Nervous System Diseases/genetics*
;
Humans
;
Signal Transduction/drug effects*
7.Preparation of baicalin-berberine complex nanocrystal enteric microspheres and pharmacodynamic evaluation of ulcerative colitis treatment in rats.
Xiao-Chao HUANG ; Yi-Wen HU ; Peng-Yu SHEN ; Rui-Hong JIAN ; Dong-Li QI ; Zhi-Dong LIU ; Jia-Xin PI
China Journal of Chinese Materia Medica 2025;50(15):4263-4274
To enhance the therapeutic efficacy of the baicalin-berberine complex(BA-BBR) in the treatment of ulcerative colitis(UC), BA-BBR nanocrystal microspheres(BA-BBR NC MS) were prepared using the dropping method. The microspheres were characterized in terms of morphology, particle size, differential scanning calorimetry(DSC), and powder X-ray diffraction(XRD). The release profiles of BA and BBR from the microspheres were measured, and the drug release mechanism was investigated. A rat model of UC was induced by 5% dextran sodium sulfate(DSS) and treated continuously for 7 days to evaluate the therapeutic effects of different formulations. The results showed that the prepared BA-BBR MS and BA-BBR NC MS were uniform gel spheres with particle sizes of(1.77±0.16) mm and(1.67±0.08) mm, respectively. After drying, the gels collapsed inward and exhibited a rough surface. During the preparation process, the BA-BBR nanocrystals(BA-BBR NC) were uniformly encapsulated within the microspheres. The release profiles of the microspheres followed a first-order kinetic model, and the 12-hour cumulative release of BA and BBR from BA-BBR NC MS was higher than that from BA-BBR MS. Compared with BA-BBR, BA-BBR NC, and BA-BBR MS, BA-BBR NC MS further alleviated UC symptoms in rats, most significantly reducing the levels of TNF-α, IL-1β, IL-6, and MPO, while increasing the level of IL-4 in colon tissues. These results indicate that BA-BBR NC MS, based on a "nano-in-micro" design, can deliver BA-BBR to the intestine and exert significant therapeutic effects in a UC rat model, suggesting it as a promising new strategy for the treatment of UC.
Animals
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Colitis, Ulcerative/metabolism*
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Rats
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Nanoparticles/chemistry*
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Microspheres
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Male
;
Berberine/administration & dosage*
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Flavonoids/administration & dosage*
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Rats, Sprague-Dawley
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Drugs, Chinese Herbal/administration & dosage*
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Humans
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Particle Size
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Tumor Necrosis Factor-alpha/immunology*
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Drug Liberation
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Drug Compounding
8.Effectiveness of arthroscopic superior capsular reconstruction using a "sandwich" patch combined with platelet-rich plasma injection in treating massive irreparable rotator cuff tears.
Wen ZOU ; Ming ZHOU ; Shaoyong FAN ; Huiming HOU ; Li GONG ; Tao XU ; Liangshen HU ; Jiang JIANG
Chinese Journal of Reparative and Reconstructive Surgery 2025;39(10):1285-1289
OBJECTIVE:
To investigate effectiveness of arthroscopic superior capsular reconstruction using a "sandwich" patch combined with platelet-rich plasma (PRP) injection in treating massive irreparable rotator cuff tears.
METHODS:
A clinical data of 15 patients (15 sides) with massive irreparable rotator cuff tears, who were admitted between September 2020 and March 2023 and met the selective criteria, was retrospectively analyzed. There were 8 males and 7 females with an average age of 62.1 years (range, 40-80 years). The rotator cuff tears were caused by trauma in 7 cases and other reasons in 8 cases. The disease duration ranged from 5 to 25 months, with an average of 17.7 months. According to the Hamada grading, the rotator cuff tears were rated as grade 1 in 2 cases, grade 2 in 8 cases, and grade 3 in 5 cases. All patients were underwent superior capsular reconstruction using the "sandwich" patches (autologous fascia lata+polypropylene patch+autologous fascia lata) combined with PRP injection on patches. The pre- and post-operative active range of motion (ROM) of the shoulder joint, American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score, University of California, Los Angeles Shoulder Rating Scale (UCLA) score, and visual analogue scale (VAS) score were recorded. The subacromial space was measured on the imaging and rotator cuff integrity was assessed based on Sugaya grading.
RESULTS:
All incisions healed by first intention after operation without any complications such as infection. All patients were followed up 12-18 months (mean, 14.4 months). At last follow-up, the active ROMs of flexion, abduction, external rotation, internal rotation of the shoulder joint, subacromial space, ASES score, Constant-Murley score, and UCLA score increased, and VAS score decreased, showing significant differences when compared with preoperative values ( P<0.05). There was no significant difference in the Sugaya grading between last follow-up and immediately after operation ( P>0.05).
CONCLUSION
For massive irreparable rotator cuff tears, arthroscopic superior capsular reconstruction using the "sandwich" patches combined with PRP injection can restore stability of the shoulder joint, relieve pain, promote rotator cuff healing, and achieve good short-term effectiveness.
Humans
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Platelet-Rich Plasma
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Female
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Male
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Middle Aged
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Aged
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Rotator Cuff Injuries/therapy*
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Arthroscopy/methods*
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Adult
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Retrospective Studies
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Aged, 80 and over
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Treatment Outcome
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Plastic Surgery Procedures/methods*
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Rotator Cuff/surgery*
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Range of Motion, Articular
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Shoulder Joint/surgery*
9.CURRENT DISTRIBUTION OF AEDES AEGYPTI IN LEIZHOU PENINSULA,ZHANJIANG CITY,GUANGDONG PROVINCE
Rui-Peng LU ; Jin-Hua DUAN ; Yu-Wen ZHONG ; Hui DENG ; Jun WU ; Li-Ping LIU ; Wei-Xiong YIN ; Feng XING ; Hui HUANG ; Chang-Jie FU ; Zong-Jing CHEN ; Ming-Ji CHENG ; Sheng-Jun HU ; Ya-Ting CHEN ; Wen-Ting GUO ; Li-Feng LIN
Acta Parasitologica et Medica Entomologica Sinica 2025;32(1):16-21
Objective To investigate the status of population dynamics and distribution changes of Aedes aegypti in Guangdong Province.Methods Continuous monitoring was conducted from May 2018 to July 2024 in Wushi Town and Qishui Town,Leizhou City,Zhanjiang City,Guangdong Province.Additionally,a survey of the distribution of Ae.aegypti along the Leizhou Peninsula coast was carried out.Results The density of Ae.aegypti in Zhanjiang showed a gradual decline from 2018 to 2024.The last detection of adult Ae.aegypti in Wushi Town was in September 2021,and the last larva was found in October 2023.No Ae.aegypti was detected in Qishui Town during surveys from 2021 to 2024.A survey of 18 coastal villages in the Leizhou Peninsula revealed no detections of Ae.aegypti.Conclusions This study provides a basis for understanding the distribution and population density fluctuations of Ae.aegypti,assessing its invasion risk,and scientifically conducting relevant prevention and control efforts.
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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