1.Effect of Acupuncture at Neiguan (PC6) on Improving Autism by Promoting Myelination Through The METTL14/m⁶A/PTEN Axis Based on “Xuanfu-Suiqiao” Theory
Wei-Li DANG ; Lü-Yuan LIANG ; Yu-Xin LI ; Zhi-Yao LI ; Sai-Dan LIU ; Jia-Lei CAO ; Rong-Ze MA ; Yun-Kai WANG ; Xiao-Qing YANG ; Bing-Qi WEI ; Bing-Xiang MA
Progress in Biochemistry and Biophysics 2026;53(5):1165-1177
ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m6A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m6A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m6A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.
2.Effect of Acupuncture at Neiguan (PC6) on Improving Autism by Promoting Myelination Through The METTL14/m⁶A/PTEN Axis Based on “Xuanfu-Suiqiao” Theory
Wei-Li DANG ; Lü-Yuan LIANG ; Yu-Xin LI ; Zhi-Yao LI ; Sai-Dan LIU ; Jia-Lei CAO ; Rong-Ze MA ; Yun-Kai WANG ; Xiao-Qing YANG ; Bing-Qi WEI ; Bing-Xiang MA
Progress in Biochemistry and Biophysics 2026;53(5):1165-1177
ObjectiveTo clarify whether METTL14 mediates the core role of acupuncture at Neiguan (PC6) in promoting myelination and improving behavior in young autistic rats through gene intervention technology. MethodsThe ASD model was established by intraperitoneal injection of valproic acid (VPA) in pregnant rats. Male offspring were intracerebroventricularly injected with adenovirus-packaged METTL14 shRNA (sh-METTL14) or its control (sh-NC) on postnatal day 1, with a model group set as well. Subsequently, the juvenile rats were divided into model group, acupuncture group, acupuncture+sh-NC group, and acupuncture+sh-METTL14 group. The acupuncture group received acupuncture at Neiguan (PC6) from postnatal day 7, once daily for 21 consecutive days. Neurobehavioral changes were evaluated by behavioral tests; METTL14 knockdown efficiency and the expression of METTL14, METTL3, and PTEN were detected by quantitative real-time PCR (qRT-PCR) and Western blot (WB); PTEN m6A levels were measured by RNA immunoprecipitation-qPCR (RIP-qPCR); myelin ultrastructure, expression of myelin basic protein (MBP) and neurofascin 155 (NF155), and dendritic spine density were observed using transmission electron microscopy (TEM), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, qRT-PCR, and primary neuron culture. ResultsBehaviorally, knockdown of METTL14 significantly counteracted the beneficial effects of acupuncture in improving self-grooming, open field exploration, three-chamber social interaction, and Morris water maze learning and memory (P<0.05, P<0.01). Compared with the acupuncture+sh-NC group, the acupuncture+sh-METTL14 group showed significantly decreased mRNA and protein expression of hippocampal METTL14 (P<0.01), and the upregulating effects of acupuncture on METTL3 and PTEN expression were reversed (P<0.01). Meanwhile, knockdown of METTL14 significantly inhibited the acupuncture-induced increase in PTEN m6A levels (P<0.01). Morphologically, knockdown of METTL14 attenuated the improvement of myelin structure by acupuncture, reversed the downregulation of MBP and upregulation of NF155 induced by acupuncture, and blocked the increase in dendritic spine density (P<0.05, P<0.01). ConclusionMETTL14 is a key molecule mediating the therapeutic effect of acupuncture at Neiguan. Acupuncture at Neiguan upregulates METTL14, thereby enhancing m6A methylation modification of PTEN mRNA to stabilize its expression, ultimately promoting myelin development and improving behavioral symptoms in ASD juvenile rats. This preliminarily reveals the modern biological connotation of “opening Xuanfu and dredging myelin”.
3.Role of IL-17A in acute inhalational pneumonia caused by highly virulent and multidrug-resistant Staphylococcus aureus
Qi KUANG ; Xiaoyu ZHU ; Lu LI ; Xueyan WANG ; Peijie YAN ; Lili ZHANG ; Meng LÜ ; Lingfei HU ; Dongsheng ZHOU ; Wenhui YANG
Acta Universitatis Medicinalis Anhui 2026;61(4):599-605
ObjectiveTo investigate the role of interleukin (IL)-17A in acute inhalational pneumonia induced by the highly drug-resistant and hypervirulent Staphylococcus aureus strain USA300-R in mice. MethodsAn acute inhalational pneumonia model was established in mice using an aerosolized pulmonary delivery technique. RNA sequencing (RNA-seq) and enzyme-linked immunosorbent assay (ELISA) were employed to examine the expression dynamics of Il17a mRNA and IL-17A protein, respectively, in the lungs of infected mice. Il17a knockout (Il17a-/-) mice were generated using CRISPR/Cas9 gene editing technology. The survival rate, body weight, bacterial load in lung tissue, and histopathological changes were compared between Il17a-/- and wild-type (WT) mice following inhalational infection with USA300-R. Results12 hours after USA300-R infection, compared to pre-infection, the expression level of Il17a mRNA in lung tissue and the level of IL-17A protein in bronchoalveolar lavage fluid (BALF) increased by approximately 50-fold (P<0.01) and 6-fold (P<0.001), respectively. Compared to WT mice, Il17a-/- mice exhibited approximately 10-fold higher bacterial loads in lung tissue at both 12 and 24 hours post-infection (P<0.001, P<0.05). However, they showed significantly attenuated lung histopathological injury, reduced alveolar wall thickening, markedly decreased neutrophil infiltration, and an approximately 50% improvement in survival rate (P<0.05). ConclusionIn acute Staphylococcus aureus USA300-R inhalational pneumonia, IL-17A contributes to bacterial clearance by recruiting neutrophils; however, excessive neutrophil infiltration exacerbates pulmonary inflammation and injury, reduces survival rates, and represents a potential therapeutic target.
4.Establishment and preliminary evaluation of a fluorescent recombinase-aided amplification assay for detection of Strongyloides stercoralis
Xiaodan CHEN ; Wanqiong CHENG ; Xiaoyin FU ; Jiayin LÜ ; Jiayue SUN ; Qiuhua BAI ; Xue HAN ; Yunliang SHI ; Dengyu LIU
Chinese Journal of Schistosomiasis Control 2026;38(2):160-168
Objective To establish a fluorescent recombinase-aided amplification (RAA) assay for detection of Strongyloides stercoralis nucleic acid and to preliminarily evaluate its performance. Methods Six sets of specific primers targeting S. stercoralis 18S ribosomal RNA (18S rRNA) gene and one fluorescent probe were designed and synthesized. The optimal primer-probe set was determined through systematic screening and optimization to establish the fluorescent RAA assay. The assay was evaluated using S. stercoralis genomic DNA at concentrations of 100, 10, and 1 pg/μL, and 100, 10, and 1 fg/μL, as well as recombinant pUC57 plasmids containing the target gene fragments at 1 × 105, 1 × 104, 1 × 103, 1 × 102, 1 × 101, 1 × 100 copies/reaction, to determine the analytical sensitivity. Genomic DNA from Ascaris lumbricoides, Ancylostoma duodenale, Enterobius vermicularis, Angiostrongylus cantonensis, Trichinella spiralis, Clonorchis sinensis, Schistosoma japonicum, and Taenia saginata was used to assess assay specificity. A total of 25 stool samples from patients suspected of S. stercoralis infection were tested by the modified Baermann funnel technique, PCR, and the established fluorescent RAA assay. The sensitivity, specificity, concordance rate and their 95% confidence intervals (CI) of these three techniques were estimated, and agreement between methods was evaluated using the Kappa coefficient. Results Exo-4 was identified as the optimal primer set screened from the six primer sets, and the best amplification performance was achieved when the final concentrations of the forward and reverse primers were 0.44 μmol/L and a probe concentration was 0.20 μmol/L. The limit of detection of the fluorescent RAA assay was 100 fg/μL for genomic DNA of S. stercoralis and 1 × 100 copies/reaction for recombinant plasmids. Specific fluorescence signals were detected within 5 min, with no cross-reactivity observed with A. lumbricoides, A. duodenale, E. vermicularis, A. cantonensis, T. spiralis, C. sinensis, S. japonicum, or T. saginata. Among the 25 clinical stool samples from patients suspected of S. stercoralis infections, the modified Baermann funnel technique and fluorescent RAA assay detected 19 positives and 6 negatives, whereas PCR detected 18 positives and 7 negatives. The fluorescent RAA assay showed a sensitivity of 100.00% [95% CI: (82.35%, 100.00%)], specificity of 100.00% [95% CI: (54.07%, 100.00%)], concordance rate of 100.00% [95% CI: (86.28%, 100.00%)], and a Kappa coefficient of 1.00 [95% CI: (1.00, 1.00)] (P < 0.001) relative to the modified Baermann funnel technique, and a sensitivity of 100.00% [95% CI: (81.47%, 100.00%)], specificity of 85.71% [95% CI: (42.13%, 99.64%)], concordance rate of 96.00% [95% CI: (79.65%, 99.90%)], and a Kappa coefficient of 0.90 [95% CI: (0.70, 1.00)] (P < 0.001). Positive amplification products emitted green fluorescence under a portable blue-light device, enabling visual interpretation of results. Conclusions The fluorescent RAA assay established in this study is rapid, highly sensitive, and highly specific. It enables detection of S. stercoralis nucleic acid under isothermal conditions and allows visual interpretation of results, providing a novel tool for rapid clinical diagnosis and field screening of S. stercoralis infections.
5.Evaluation of the Histological Staining Performance of Rat Eyeball Sections Prepared Using a Self-Developed Fixative
Xiaohang TANG ; Yingmin GU ; Yangyang LÜ ; Mingshu HUANG ; Xuesong TIAN
Laboratory Animal and Comparative Medicine 2026;46(2):261-270
ObjectiveTo compare the histological staining performance of four various tissue fixatives, including a self-developed fixative, for preparing paraffin sections of rat eyeball tissue. MethodsTwenty 5-week-old male Sprague-Dawley (SD) rats were randomly divided into 4 groups (n=5 per group). After anesthesia by intraperitoneal injection of Zoletil™ 50 at a dose of 45 mg/kg body weight, the rats were euthanized by exsanguination via the abdominal aorta. Bilateral eyeballs were carefully extracted intact and fixed for 72 h in 10% formaldehyde fixative, glutaraldehyde-formaldehyde mixed fixative, Davidson's fixative, and self-developed fixative, respectively. After fixation, the eyeballs were longitudinally sectioned along the optic nerve, with the portions containing the optic nerve preserved. The tissues were then dehydrated, embedded, and sectioned. Following hematoxylin and eosin (HE) staining, histological staining quality was compared among ocular structures including the cornea, lens, and retina. ResultsThe overall appearance of rat eyeballs showed marked shrinkage in the 10% formaldehyde group and the glutaraldehyde-formaldehyde group, whereas the eye morphology remained round and intact in the modified Davidson's fixative group and self-developed fixative group. The corneal stroma exhibited obvious rupture, and the cells were arranged in folded arrangement in the modified Davidson's fixative group, 10% formaldehyde group, and self-developed fixative group. In contrast, the corneal cells in the glutaraldehyde-formaldehyde group were neatly arranged, showing no rupture or folding, and exhibited clear staining, indicating the highest quality of corneal sectioning among all groups. In the 10% formaldehyde group, cracks were observed in the equatorial and cortical regions of the lens, but the lens fiber structure remained intact. The lenses in the modified Davidson's fixative group showed extensive rupture and detachment. The glutaraldehyde-formaldehyde group displayed only slight cracks at the equator. In the self-developed fixative group, mild red folding was limited to the peripheral lens region, with the remaining structures intact and unbroken. These findings indicated that the glutaraldehyde-formaldehyde and self-developed fixative groups achieved the best lens sectioning quality. The retina was severely detached from the choroid/sclera layer, with extensive rupture of each cellular layer in the 10% formaldehyde fixative group. In the glutaraldehyde-formaldehyde group, partial detachment between the retina and choroid/sclera was observed. The outer plexiform layer and nerve fiber layer showed separation with edema, while the cells in all layers were neatly arranged. In both the Davidson's fixative and the self-developed fixative groups, the retina remained intact without rupture, and no structural separation was observed in any layer. Both demonstrated advantages in preserving the integrity and orderly arrangement of all retinal layers; however, the self-developed fixative group exhibited greater contrast. ConclusionThe choice of fixative significantly affects the morphological preservation of various structures in the rat eye. The self-developed fixative demonstrates the best overall performance in maintaining overall eye morphology, the structural integrity of the lens, and retinal adhesion. For studies focusing solely on the corneal structure, the glutaraldehyde-formaldehyde mixed fixative is recommended. The 10% formaldehyde fixative exhibits unsatisfactory fixation effects for all the aforementioned ocular structures and is not recommended for detailed morphological studies of eyeball tissues.
6.China - Africa cooperation for tropical diseases control: current status and future priorities
Shenning LU ; Kun YANG ; Yingjun QIAN ; Duoquan WANG ; Shan LÜ ; Xiaonong ZHOU
Chinese Journal of Schistosomiasis Control 2026;38(1):1-7
Tropical diseases, the transmission of which is affected by multiple natural and social factors, pose a great challenge to global public health, notably in African countries. During the past several decades, China and African countries have continuously collaborated for the control of neglected tropical diseases and malaria, which has become an important part of global South-to-South cooperation and global health governance. This article reviews the history of China-Africa cooperation for tropical diseases control, summarizes the experiences and achievements over the past decade, analyzes the current challenges in the coopera tion, and proposes future recommendations. The China-Africa cooperation has achieved significant progress in the control of tropical diseases, such as malaria, schistosomiasis, and filariasis, and established a China-Africa cooperation network for tropical diseases control. Through the "Three-Step" strategy of China-Africa cooperation, the effectiveness of China's integrated control strategies has been validated in Africa, and the application of China's tropical disease control technologies has been promoted in African disease-epidemic countries. Currently, China-Africa collaboration, however, still experiences multiple realistic challenges, such as insufficient resources, difficulty in technology transfer, and weak primary healthcare systems. In the future, both sides are recommended to further strengthen policy coordination, deepen technological cooperation, innovate cooperation models, aiming to continuously promote the high-quality development of China-Africa cooperation for tropical diseases control.
7.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.
8.Nanopackaged Astaxanthin Improves Demyelination in Multiple Sclerosis Model Mice by Scavenging Excessive Endogenous Formaldehyde
Wan-Jia LÜ ; Xin ZENG ; Zhi-Qian TONG ; Yang XING ; Xu YANG ; Mei-Na WU ; Ping MA
Progress in Biochemistry and Biophysics 2026;53(2):442-457
ObjectiveMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS); however, its underlying neurological pathogenic mechanisms remain incompletely understood. Endogenous formaldehyde (FA), a metabolic byproduct of methylation-demethylation cycles, has recently been implicated in neurotoxicity, oxidative damage, and cognitive impairment. This study aimed to investigate whether excessive FA contributes to myelin sheath demyelination in mice and to evaluate the protective effects and mechanisms of two FA-elimination strategies: sodium bisulfite (NaHSO3), a classical FA scavenger, and polyethylene glycol-modified astaxanthin nanoparticles (PEG-ATX@NPs), a brain-targeted nano-antioxidant formulation. MethodsA chronic demyelination model was established by feeding female C57BL/6J mice a diet containing 0.2% cuprizone (CPZ) for four weeks, followed by a two-week intervention period. Eighty mice were randomly assigned to four groups: NS (normal saline), CPZ+NS, CPZ+NaHSO3, and CPZ+PEG-ATX@NPs. Behavioral tests, including open-field, Y-maze, and pole-climbing assays, were conducted to assess locomotor activity, motor coordination, and working memory. FA levels in serum, corpus callosum, and spinal cord were measured using an Na-FA fluorescent probe and quantified via in vivo and ex vivo fluorescence imaging. Neuroinflammatory responses were evaluated by measuring TNF-α, IL-1β, and IL-6 levels using ELISA, while oxidative stress was assessed by reactive oxygen species (ROS) fluorescence intensity. Demyelination was examined via Luxol fast blue staining, and microglial activation was analyzed by Iba1 immunofluorescence. Correlation analyses were performed to explore relationships among FA levels, inflammatory cytokines, ROS intensity, and behavioral parameters. ResultsCompared with the NS group, mice in the CPZ+NS group exhibited significant weight loss, impaired motor coordination and memory, and markedly reduced myelin regeneration (P<0.05). FA levels and pro-inflammatory cytokines were significantly elevated in serum, corpus callosum, and spinal cord (P<0.05). FA-associated fluorescence in brain and spinal tissues, as well as ROS intensity across all tissues examined, also increased substantially (P<0.05). CPZ treatment induced pronounced microglial activation and severe demyelination in the corpus callosum (P<0.01). Both NaHSO3 and PEG-ATX@NPs effectively reduced FA accumulation in the brain and spinal cord, attenuated demyelination, suppressed microglial activation, decreased inflammatory cytokine levels, and improved motor and cognitive performance. These results confirm that CPZ induced severe demyelination accompanied by oxidative stress, neuroinflammation, and abnormal FA accumulation. Following intervention with either NaHSO3 or PEG-ATX@NPs, endogenous FA levels in the CNS were substantially reduced. Both treatments alleviated demyelination and significantly decreased the number of activated microglia. Levels of TNF-α, IL-1β, and IL-6 in serum, corpus callosum, and spinal cord were downregulated. Behavioral performance improved significantly, as evidenced by enhanced locomotor activity, better coordination, and improved memory function. These findings indicate that both FA-scavenging agents mitigate CPZ-induced biochemical and behavioral abnormalities. ConclusionThis study demonstrates that excessive endogenous FA is closely associated with cognitive impairment, inflammatory dysregulation, and demyelination in a CPZ-induced chronic demyelination mouse model. Clearing abnormally elevated FA effectively reduces neuroinflammation, suppresses microglial overactivation, decreases oxidative stress, and alleviates demyelination, ultimately improving motor and cognitive outcomes in mice. These results suggest that targeting endogenous FA represents a promising therapeutic strategy for MS and other demyelinating disorders. Further investigations are warranted to explore the long-term safety, dosage optimization, and molecular pathways involved in FA-mediated neurotoxicity.
9.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.
10.Nanopackaged Astaxanthin Improves Demyelination in Multiple Sclerosis Model Mice by Scavenging Excessive Endogenous Formaldehyde
Wan-Jia LÜ ; Xin ZENG ; Zhi-Qian TONG ; Yang XING ; Xu YANG ; Mei-Na WU ; Ping MA
Progress in Biochemistry and Biophysics 2026;53(2):442-457
ObjectiveMultiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS); however, its underlying neurological pathogenic mechanisms remain incompletely understood. Endogenous formaldehyde (FA), a metabolic byproduct of methylation-demethylation cycles, has recently been implicated in neurotoxicity, oxidative damage, and cognitive impairment. This study aimed to investigate whether excessive FA contributes to myelin sheath demyelination in mice and to evaluate the protective effects and mechanisms of two FA-elimination strategies: sodium bisulfite (NaHSO3), a classical FA scavenger, and polyethylene glycol-modified astaxanthin nanoparticles (PEG-ATX@NPs), a brain-targeted nano-antioxidant formulation. MethodsA chronic demyelination model was established by feeding female C57BL/6J mice a diet containing 0.2% cuprizone (CPZ) for four weeks, followed by a two-week intervention period. Eighty mice were randomly assigned to four groups: NS (normal saline), CPZ+NS, CPZ+NaHSO3, and CPZ+PEG-ATX@NPs. Behavioral tests, including open-field, Y-maze, and pole-climbing assays, were conducted to assess locomotor activity, motor coordination, and working memory. FA levels in serum, corpus callosum, and spinal cord were measured using an Na-FA fluorescent probe and quantified via in vivo and ex vivo fluorescence imaging. Neuroinflammatory responses were evaluated by measuring TNF-α, IL-1β, and IL-6 levels using ELISA, while oxidative stress was assessed by reactive oxygen species (ROS) fluorescence intensity. Demyelination was examined via Luxol fast blue staining, and microglial activation was analyzed by Iba1 immunofluorescence. Correlation analyses were performed to explore relationships among FA levels, inflammatory cytokines, ROS intensity, and behavioral parameters. ResultsCompared with the NS group, mice in the CPZ+NS group exhibited significant weight loss, impaired motor coordination and memory, and markedly reduced myelin regeneration (P<0.05). FA levels and pro-inflammatory cytokines were significantly elevated in serum, corpus callosum, and spinal cord (P<0.05). FA-associated fluorescence in brain and spinal tissues, as well as ROS intensity across all tissues examined, also increased substantially (P<0.05). CPZ treatment induced pronounced microglial activation and severe demyelination in the corpus callosum (P<0.01). Both NaHSO3 and PEG-ATX@NPs effectively reduced FA accumulation in the brain and spinal cord, attenuated demyelination, suppressed microglial activation, decreased inflammatory cytokine levels, and improved motor and cognitive performance. These results confirm that CPZ induced severe demyelination accompanied by oxidative stress, neuroinflammation, and abnormal FA accumulation. Following intervention with either NaHSO3 or PEG-ATX@NPs, endogenous FA levels in the CNS were substantially reduced. Both treatments alleviated demyelination and significantly decreased the number of activated microglia. Levels of TNF-α, IL-1β, and IL-6 in serum, corpus callosum, and spinal cord were downregulated. Behavioral performance improved significantly, as evidenced by enhanced locomotor activity, better coordination, and improved memory function. These findings indicate that both FA-scavenging agents mitigate CPZ-induced biochemical and behavioral abnormalities. ConclusionThis study demonstrates that excessive endogenous FA is closely associated with cognitive impairment, inflammatory dysregulation, and demyelination in a CPZ-induced chronic demyelination mouse model. Clearing abnormally elevated FA effectively reduces neuroinflammation, suppresses microglial overactivation, decreases oxidative stress, and alleviates demyelination, ultimately improving motor and cognitive outcomes in mice. These results suggest that targeting endogenous FA represents a promising therapeutic strategy for MS and other demyelinating disorders. Further investigations are warranted to explore the long-term safety, dosage optimization, and molecular pathways involved in FA-mediated neurotoxicity.

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