Photobiomodulation inhibits neuronal firing in the superficial but not deep layer of a rat spinal dorsal horn.

Photobiomodulation (PBM) has attracted attention as a treatment for chronic pain. Previous studies have reported that PBM of the sciatic nerve inhibits neuronal firing in the superficial layers (lamina I-II) of the spinal dorsal horn of rats, which is evoked by mechanical stimulation that corresponds to noxious stimuli. However, the effects of PBM on the deep layers (lamina III-IV) of the spinal dorsal horn, which receive inputs from innocuous stimuli, remain poorly understood. In this study, we examined the effect of PBM of the sciatic nerve on firing in the deep layers of the spinal dorsal horn evoked by mechanical stimulation. Before and after PBM, mechanical stimulation was administered to the cutaneous receptive field using 0.6-26.0 g von Frey filaments (vFFs), and vFF-evoked firing in the deep layers of the spinal dorsal horn was recorded. The vFF-evoked firing frequencies were not altered after the PBM for any of the vFFs. The inhibition rate for 26.0 g vFF-evoked firing was approximately 13 % in the deep layers and 70 % in the superficial layers. This suggests that PBM selectively inhibits the transmission of pain information without affecting the sense of touch. PBM has the potential to alleviate pain while preserving the sense of touch.

Lycium barbarum glycopeptide ameliorates motor and visual deficits in autoimmune inflammatory diseases.

BACKGROUND: Lycium barbarum glycopeptide (LbGp), extracted from the traditional Chinese medicine (TCM) of Lycium barbarum (LB), provides a neuroprotective effect against neurodegenerative and neuroimmune disorders contributing to its immunomodulatory and anti-inflammatory roles. Neuromyelitis optica spectrum disorders (NMOSD) is an autoimmune-mediated central nervous system (CNS) demyelinating disease, clinically manifested as transverse myelitis (TM) and optic neuritis. However, no drug has been demonstrated to be effective in relieving limb weakness and visual impairment of NMOSD patients. PURPOSE: This study investigates the potential role of LbGp in ameliorating pathologic lesions and improving neurological dysfunction during NMOSD progression, and to elucidate the underlying mechanisms for the first time. STUDY DESIGN: We administrate LbGp in experimental NMOSD models in ex vivo and in vivo to explore its effect on NMOSD. METHODS: To evaluate motor function, both rotarod and gait tasks were performed in systemic NMOSD mice models. Furthermore, we assessed the severity of NMO-like lesions of astrocytes, organotypic cerebellar slices, as well as brain, spinal cord and optic nerve sections from NMOSD mouse models with LbGp treatment by immunofluorescent staining. In addition, demyelination levels in optic nerve were measured by G-ratio through Electro-microscopy (EM). And inflammation response was explored through detecting the protein levels of proinflammatory cytokines and NF-κB signaling in astrocytic culture medium and spinal cord homogenates respectively by Elisa and by Western blotting. RESULTS: LbGp could significantly reduce astrocytes injury, demyelination, and microglial activation in NMOSD models. In addition, LbGp also improved locomotor and visual dysfunction through preventing neuron and retinal ganglion cells (RGCs) from inflammatory attack in a systemic mouse model. Mechanistically, LbGp inhibits proinflammatory factors release via inhibition of NF-κB signaling in NMOSD models. CONCLUSION: This study provides evidence to develop LbGp as a functional TCM for the clinical treatment of NMOSD.

Tetramethylpyrazine-loaded electroconductive hydrogels promote tissue repair after spinal cord injury by protecting the blood-spinal cord barrier and neurons.

Spinal cord injury (SCI) usually induces profound microvascular dysfunction. It disrupts the integrity of the blood-spinal cord barrier (BSCB), which could trigger a cascade of secondary pathological events that manifest as neuronal apoptosis and axonal demyelination. These events can further lead to irreversible neurological impairments. Thus, reducing the permeability of the BSCB and maintaining its substructural integrity are essential to promote neuronal survival following SCI. Tetramethylpyrazine (TMP) has emerged as a potential protective agent for treating the BSCB after SCI. However, its therapeutic potential is hindered by challenges in the administration route and suboptimal bioavailability, leading to attenuated clinical outcomes. To address this challenge, traditional Chinese medicine, TMP, was used in this study to construct a drug-loaded electroconductive hydrogel for synergistic treatment of SCI. A conductive hydrogel combined with TMP demonstrates good electrical and mechanical properties as well as superior biocompatibility. Furthermore, it also facilitates sustained local release of TMP at the implantation site. Furthermore, the TMP-loaded electroconductive hydrogel could suppress oxidative stress responses, thereby diminishing endothelial cell apoptosis and the breakdown of tight junction proteins. This concerted action repairs BSCB integrity. Concurrently, myelin-associated axons and neurons are protected against death, which meaningfully restore neurological functions post spinal cord injury. Hence, these findings indicate that combining the electroconductive hydrogel with TMP presents a promising avenue for potentiating drug efficacy and synergistic repair following SCI.

Neurological recovery and neurogenesis by curcumin sustained-release system cross-linked with an acellular spinal cord scaffold in rat spinal cord injury: Targeting NLRP3 inflammasome pathway.

In the context of treating spinal cord injury (SCI), the modulation of inflammatory responses, and the creation of a suitable region for tissue regeneration may present a promising approach. This study aimed to evaluate the effects of curcumin (Cur)-loaded bovine serum albumin nanoparticles (Cur-BSA NPs) cross-linked with an acellular spinal cord scaffold (ASCS) on the functional recovery in a rat model of SCI. We developed an ASCS using chemical and physical methods. Cur-BSA, and blank (B-BSA) NPs were fabricated and cross-linked with ASCS via EDC-NHS, resulting in the production of Cur-ASCS and B-ASCS. We assessed the properties of scaffolds and NPs as well as their cross-links. Finally, using a male rat hemisection model of SCI, we investigated the consequences of the resulting scaffolds. The inflammatory markers, neuroregeneration, and functional recovery were evaluated. Our results showed that Cur was efficiently entrapped at the rate of 42% ± 1.3 in the NPs. Compared to B-ASCS, Cur-ASCS showed greater effectiveness in the promotion of motor recovery. The implantation of both scaffolds could increase the migration of neural stem cells (Nestin- and GFAP-positive cells) following SCI with the superiority of Cur-ASCS. Cur-ASCS was successful to regulate the gene expression and protein levels of NLRP3, ASC, and Casp1in the spinal cord lesion. Our results indicate that using ASCS can lead to the entrance of cells into the scaffold and promote neurogenesis. However, Cur-ASCS had greater effects in terms of inflammation relief and enhanced neurogenesis.

Longitudinal Magnetic Resonance Imaging Tracking of Transplanted Neural Progenitor Cells in the Spinal Cord Utilizing the Bright-Ferritin Mechanism.

Human neural progenitor cells (hNPCs) hold promise for treating spinal cord injury. Studies to date have focused on improving their regenerative potential and therapeutic effect. Equally important is ensuring successful delivery and engraftment of hNPCs at the injury site. Unfortunately, no current imaging solution for cell tracking is compatible with long-term monitoring in vivo. The objective of this study was to apply a novel bright-ferritin magnetic resonance imaging (MRI) mechanism to track hNPC transplants longitudinally and on demand in the rat spinal cord. We genetically modified hNPCs to stably overexpress human ferritin. Ferritin-overexpressing (FT) hNPCs labeled with 0.2 mM manganese provided significant T1-induced bright contrast on in vitro MRI, with no adverse effect on cell viability, morphology, proliferation, and differentiation. In vivo, 2 M cells were injected into the cervical spinal cord of Rowett nude rats. MRI employed T1-weighted acquisitions and T1 mapping on a 3 T scanner. Conventional short-term cell tracking was performed using exogenous Mn labeling prior to cell transplantation, which displayed transient bright contrast on MRI 1 day after cell transplantation and disappeared after 1 week. In contrast, long-term cell tracking using bright-ferritin allowed on-demand signal recall upon Mn supplementation and precise visualization of the surviving hNPC graft. In fact, this new cell tracking technology identified 7 weeks post-transplantation as the timepoint by which substantial hNPC integration occurred. Spatial distribution of hNPCs on MRI matched that on histology. In summary, bright-ferritin provides the first demonstration of long-term, on-demand, high-resolution, and specific tracking of hNPCs in the rat spinal cord.

Electroacupuncture suppresses neuronal ferroptosis to relieve chronic neuropathic pain.

Growing evidence supports the analgesic efficacy of electroacupuncture (EA) in managing chronic neuropathic pain (NP) in both patients and NP models induced by peripheral nerve injury. However, the underlying mechanisms remain incompletely understood. Ferroptosis, a novel form of programmed cell death, has been found to be activated during NP development, while EA has shown potential in promoting neurological recovery following acute cerebral injury by targeting ferroptosis. In this study, to investigate the detailed mechanism underlying EA intervention on NP, male Sprague-Dawley rats with chronic constriction injury (CCI)-induced NP model received EA treatment at acupoints ST36 and GV20 for 14 days. Results demonstrated that EA effectively attenuated CCI-induced pain hypersensitivity and mitigated neuron damage and loss in the spinal cord of NP rats. Moreover, EA reversed the oxidative stress-mediated spinal ferroptosis phenotype by upregulating reduced expression of xCT, glutathione peroxidase 4 (GPX4), ferritin heavy chain (FTH1) and superoxide dismutase (SOD) levels, and downregulating increased expression of acyl-CoA synthetase long-chain family member 4 (ACSL4), malondialdehyde levels and iron overload. Furthermore, EA increased the immunofluorescence co-staining of GPX4 in neurons cells of the spinal cord of CCI rats. Mechanistic analysis unveiled that the inhibition of antioxidant pathway of Nrf2 signalling via its specific inhibitor, ML385, significantly countered EA's protective effect against neuronal ferroptosis in NP rats while marginally diminishing its analgesic effect. These findings suggest that EA treatment at acupoints ST36 and GV20 may protect against NP by inhibiting neuronal ferroptosis in the spinal cord, partially through the activation of Nrf2 signalling.

Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery.

BACKGROUND: Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system. PURPOSE: To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis. METHODS: First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol. RESULTS: Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI. CONCLUSION: Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

Changes in the excitability of anterior horn cells in a mental rotation task of body parts.

INTRODUCTION/AIMS: Mental rotation (MR), a tool of implicit motor imagery, is the ability to rotate mental representations of two- or three-dimensional objects. Although many reports have described changes in brain activity during MR tasks, it is not clear whether the excitability of anterior horn cells in the spinal cord can be changed. In this study, we examined whether MR tasks of hand images affect the excitability of anterior horn cells using F-wave analysis. METHODS: Right-handed, healthy participants were recruited for this study. F-waves of the right abductor pollicis brevis were recorded after stimulation of the right median nerve at rest, during a non-MR task, and during an MR task. The F-wave persistence and the F/M amplitude ratio were calculated and analyzed. RESULTS: Twenty participants (11 men and 9 women; mean age, 29.2 ± 4.4 years) were initially recruited, and data from the 18 that met the inclusion criteria were analyzed. The F-wave persistence was significantly higher in the MR task than in the resting condition (p = .001) or the non-MR task (p = .012). The F/M amplitude ratio was significantly higher in the MR task than in the resting condition (p = .019). DISCUSSION: The MR task increases the excitability of anterior horn cells corresponding to the same body part. MR tasks may have the potential for improving motor function in patients with reduced excitability of the anterior horn cells, although this methodology must be further verified in a clinical setting.

Electroacupuncture attenuates nociceptive behaviors in a mouse model of cancer pain.

Pain is a major symptom in cancer patients, and cancer-induced bone pain (CIBP) is the most common type of moderate and severe cancer-related pain. The current available analgesic treatments for CIBP have adverse effects as well as limited therapeutic effects. Acupuncture is proved effective in pain management as a safe alternative therapy. We evaluated the analgesic effect of acupuncture in treatment of cancer pain and try to explore the underlying analgesic mechanisms. Nude mice were inoculated with cancer cells into the left distal femur to establish cancer pain model. Electroacupuncture (EA) treatment was applied for the xenograft animals. Pain behaviors of mice were evaluated, followed by the detections of neuropeptide-related and inflammation-related indicators in peripheral and central levels. EA treatment alleviated cancer-induced pain behaviors covering mechanical allodynia, thermal hyperalgesia and spontaneous pain, and also down-regulated immunofluorescence expressions of neuropeptide CGRP and p75 in the skin of affected plantar area in xenograft mice, and inhibited expressions of overexpressed neuropeptide-related and inflammation-related protein in the lumbar spinal cord of xenograft mice. Overall, our findings suggest that EA treatment ameliorated cancer-induced pain behaviors in the mouse xenograft model of cancer pain, possibly through inhibiting the expressions of neuropeptide-related and inflammation-related protein in central level following tumor cell xenografts.

Inhibitory effect of acupoint electrostimulation with different layers and intensities on muscular inflammatory pain and spinal WDR neuron activity. / ç©´ä½ä¸åŒå±‚æ¬¡å’Œå¼ºåº¦ç”µåˆºæ¿€ç¼“è§£è‚Œè‚‰ç‚Žæ€§ç—›åŠå¯¹è„Šé«“èƒŒè§’å¹¿åŠ¨åŠ›ç¥žç»å ƒçš„æŠ‘åˆ¶ä½œç”¨.

OBJECTIVES: To observe the analgesic effects of different levels and intensities of electrical stimulation on the local acupoints in the pain source area and their impact on wide dynamic range (WDR) neurons in the spinal dorsal horn, in order to provide a basis for selecting appropriate parameters for electroacupuncture (EA) stimulation. METHODS: Wistar rats were used in 3 parts of the experiment. Complete Freund's adjuvant was used to establish a model of inflammation-induced pain in the gastrocnemius muscle. After modeling, 6 rats were randomly selected for multi-channel extracellular electrophysiological recording of the electrical activity of WDR neurons, to determine the threshold for activating the A-component (Ta) and the C-component (Tc), which were used as the intervention intensities for skin transcutaneous electrical acupoint stimulation (TEAS) or EA. Thirty-six rats were randomly divided into normal , model , TEAS-Ta , TEAS-Tc, EA-Ta , and EA-Tc groups, with 6 rats in each group. In the pain source area , Ta or Tc intensity of TEAS or EA intervention at"Chengshan"(BL57) was performed for 30 min each time, once a day, for 3 consecutive days. A small animal pressure pain measurement instrument was used to measure the mechanical pressure pain threshold of the gastrocnemius muscle in rats, and the Von Frey filament was used to measure the mechanical pain threshold of the footpad. Thirteen rats were randomly selected to observe the immediate responsiveness of WDR neurons to Ta/Tc intensity of EA or TEAS in BL57. RESULTS: The thresholds of TEAS to activate WDR neuron A-component or C-component were (2.43±0.57) mA and (7.00±1.34) mA, respectively, while the thresholds for EA to activate muscle WDR neuron A-component or C-component were (0.72±0.34) mA and (1.58±0.35) mA, respectively. After injection of CFA into the gastrocnemius muscle, compared with the normal group both the mechanical pressure pain threshold of the gastrocnemius muscle and the mechanical pain threshold of the footpad of rats in the model group were significantly decreased (P<0.001). After TEAS-Ta, TEAS-Tc or EA-Ta intervention in the BL57, both the mechanical pressure pain threshold of the gastrocnemius muscle and the mechanical pain threshold of the footpad were significantly higher than those in the model group (P<0.05, P<0.001). Compared with the normal group, the electrical threshold for evoking WDR neuron C-component discharge was significantly decreased (P<0.001) in the model group, while increased after TEAS-Ta, TEAS-Tc, or EA-Ta intervention (P<0.01) compared with the model group. The evoked discharge frequency of muscle WDR neurons decreased significantly after immediate intervention with TEAS-Ta, TEAS-Tc, or EA-Ta (P<0.01, P<0.05). EA-Tc had no significant improvement on the evoked electrical activity of WDR neurons or pain behavior. CONCLUSIONS: TEAS-Ta, TEAS-Tc, or EA-Ta can all alleviate the local and footpad mechanical pain in rats with muscle inflammation and inhibit the responsiveness of WDR neurons, indicating that different intensities are required for analgesic effects at different levels of acupoints in the pain source area.

Effect of electroacupuncture of "Jiaji" (EX-B2) on NOD-like receptor protein 3 mediated pyroptosis in spinal cord tissue of rats with acute spinal cord injury. / å¤¹è„Šç”µé’ˆå¯¹æ€¥æ€§è„Šé«“æŸä¼¤å¤§é¼ è„Šé«“ç»„ç»‡NODæ ·å—ä½“çƒ­è›‹ç™½ç»“æž„åŸŸç›¸å ³è›‹ç™½3介导的细胞焦亡的影响.

OBJECTIVES: To observe the effect of electroacupuncture (EA) stimulation of "Jiaji"(EX-B2) on motor function, histomorphology, and expression of NOD-like receptor protein 3 (NLRP3) and N-terminal domain of gasdermin D (GSDMD-N) in the spinal cord tissue of rats with spinal cord injury (SCI), so as to explore its mechanism underlying improvement of SCI. METHODS: Forty eight female SD rats were randomly divided into sham surgery (sham), SCI model (model), EA, and NLRP3 agonist (monosodium urate, MSU) combined with Jiaji EA (MSU+EA) groups, with 12 rats in each group which were further divided into 3 d and 7 d subgroups, with 6 rats at each time point. Two EA groups received EA stimulation of EX-B2 with a frequency of 100 Hz, electrical current of 1-2 mA for 30 min, once a day for 3 or 7 days. After 5 min, 6 h, and 24 h of modeling, rats of the MSU+EA group received intraperitoneal injection of MSU (200 µg/kg, 200 µg/mL) . The motor function was evaluated using Basso-Beattie-Bresnahan (BBB) scale, the morphological structure of rat spinal cord tissue was observed by H.E. staining. The expression of pyroptosis related factors NLRP3, cleaved Caspase-1 and GSDMD-N of the spinal cord was observed by using immunohistochemistry and Western blot separately, the expression and localization of Iba-1 and GSDMD-N in the spinal cord tissue were observed using immunofluorescence double staining method. RESULTS: Compared with the sham group, the BBB scores after modeling and on day 3 and 7 were decreased (P<0.05), while the average OD values (immunoactivity) and expression levels of NLRP3, cleaved Caspase-1 and GSDMD-N proteins, and the immunofluorescence intensity of Iba-1/GSDMD-N (co-expression) of the spinal cord tissues on day 3 and 7 were significantly increased in the model group (P<0.05). In comparison with the model group, the BBB scores on day 3 and 7 were obviously increased (P<0.05), while the immunoactivity and expression levels of NLRP3, cleaved Caspase-1 and GSDMD proteins, and the immunofluorescence intensity of Iba-1/GSDMD-N on day 3 and 7 significantly down-regulated in the EA group (P<0.05) but not in the MSU+EA group (P>0.05), suggesting an elimination of the effects of EA after administration of NLRP3 agonist (MSU). H.E. staining showed obvious bleeding area in the spinal cord tissue, loose tissue and inflammatory cell infiltration on day 3 after modeling, and basic absorption of the bleeding, loose tissue, obvious vacuolar changes of the white matter area, loss and contraction of neurons with infiltration of a large number of inflammatory cells, which was milder in the EA group but not in the MSU+EA group. CONCLUSIONS: EA of EX-B2 can improve the motor function of SCI rats, which may be related to its functions in inhibiting pyroptosis of microglia mediated by NLRP3/Caspase-1 signaling pathway.

GPR39 regulated spinal glycinergic inhibition and mechanical inflammatory pain.

G protein-coupled receptor 39 (GPR39) senses the change of extracellular divalent zinc ion and signals through multiple G proteins to a broad spectrum of downstream effectors. Here, we found that GPR39 was prevalent at inhibitory synapses of spinal cord somatostatin-positive (SOM+) interneurons, a mechanosensitive subpopulation that is critical for the conveyance of mechanical pain. GPR39 complexed specifically with inhibitory glycine receptors (GlyRs) and helped maintain glycinergic transmission in a manner independent of G protein signalings. Targeted knockdown of GPR39 in SOM+ interneurons reduced the glycinergic inhibition and facilitated the excitatory output from SOM+ interneurons to spinoparabrachial neurons that engaged superspinal neural circuits encoding both the sensory discriminative and affective motivational domains of pain experience. Our data showed that pharmacological activation of GPR39 or augmenting GPR39 interaction with GlyRs at the spinal level effectively alleviated the sensory and affective pain induced by complete Freund's adjuvant and implicated GPR39 as a promising therapeutic target for the treatment of inflammatory mechanical pain.

Chemogenetics Modulation of Electroacupuncture Analgesia in Mice Spared Nerve Injury-Induced Neuropathic Pain through TRPV1 Signaling Pathway.

Neuropathic pain, which is initiated by a malfunction of the somatosensory cortex system, elicits inflammation and simultaneously activates glial cells that initiate neuroinflammation. Electroacupuncture (EA) has been shown to have therapeutic effects for neuropathic pain, although with uncertain mechanisms. We suggest that EA can reliably cure neuropathic disease through anti-inflammation and transient receptor potential V1 (TRPV1) signaling pathways from the peripheral to the central nervous system. To explore this, we used EA to treat the mice spared nerve injury (SNI) model and explore the underlying molecular mechanisms through novel chemogenetics techniques. Both mechanical and thermal pain were found in SNI mice at four weeks (mechanical: 3.23 ± 0.29 g; thermal: 4.9 ± 0.14 s). Mechanical hyperalgesia was partially attenuated by 2 Hz EA (mechanical: 4.05 ± 0.19 g), and thermal hyperalgesia was fully reduced (thermal: 6.22 ± 0.26 s) but not with sham EA (mechanical: 3.13 ± 0.23 g; thermal: 4.58 ± 0.37 s), suggesting EA's specificity. In addition, animals with Trpv1 deletion showed partial mechanical hyperalgesia and no significant induction of thermal hyperalgesia in neuropathic pain mice (mechanical: 4.43 ± 0.26 g; thermal: 6.24 ± 0.09 s). Moreover, we found increased levels of inflammatory factors such as interleukin-1 beta (IL1-ß), IL-3, IL-6, IL-12, IL-17, tumor necrosis factor alpha, and interferon gamma after SNI modeling, which decreased in the EA and Trpv1-/- groups rather than the sham group. Western blot and immunofluorescence analysis showed similar tendencies in the dorsal root ganglion, spinal cord dorsal horn, somatosensory cortex (SSC), and anterior cingulate cortex (ACC). In addition, a novel chemogenetics method was used to precisely inhibit SSC to ACC activity, which showed an analgesic effect through the TRPV1 pathway. In summary, our findings indicate a novel mechanism underlying neuropathic pain as a beneficial target for neuropathic pain.

In Situ Reaction-Generated Aldehyde-Scavenging Polypeptides-Curcumin Conjugate Nanoassemblies for Combined Treatment of Spinal Cord Injury.

The microenvironment after traumatic spinal cord injury (SCI) involves complex pathological processes, including elevated oxidative stress, accumulated reactive aldehydes from lipid peroxidation, excessive immune cell infiltration, etc. Unfortunately, most of current neuroprotection therapies cannot cope with the intricate pathophysiology of SCI, leading to scant treatment efficacies. Here, we developed a facile in situ reaction-induced self-assembly method to prepare aldehyde-scavenging polypeptides (PAH)-curcumin conjugate nanoassemblies (named as PFCN) for combined neuroprotection in SCI. The prepared PFCN could release PAH and curcumin in response to oxidative and acidic SCI microenvironment. Subsequently, PFCN exhibited an effectively neuroprotective effect through scavenging toxic aldehydes as well as reactive nitrogen and oxygen species in neurons, modulating microglial M1/M2 polarization, and down-regulating the expression of inflammation-related cytokines to inhibit neuroinflammation. The intravenous administration of PFCN could significantly ameliorate the malignant microenvironment of injured spinal cord, protect the neurons, and promote the motor function recovery in the contusive SCI rat model.

Effect of electroacupuncture of Governor Vessel on mitochondrial fusion and proliferation and differentiation of neural stem cells in spinal cord injury rats. / ç”µé’ˆç£è„‰å¯¹è„Šé«“æŸä¼¤å¤§é¼ è„Šé«“ç»„ç»‡çº¿ç²’ä½“èžåˆåŠç¥žç»å¹²ç»†èƒžå¢žæ®–åˆ†åŒ–çš„å½±å“.

OBJECTIVES: To observe the effect of electroacupuncture (EA) at "Dazhui" (GV14) and "Jizhong"(GV6) of the Governor Vessel (GV) on mitochondrial fusion and neural stem cell (NSC) proliferation and differentiation in the spinal cord of rats with spinal cord injury (SCI), so as to investigate its mechanisms underlying improvement of SCI. METHODS: SD rats were randomly divided into sham operation, model and EA groups, with 15 rats in each group. The SCI model was established by using a precision impactor. EA (20 Hz/100 Hz, 1-2 mA) was applied to GV14 and GV6 for 30 min, once daily for 14 days. The rats' hindlimb locomotor function in each group was assessed using the Basso-Beattie-Bresnahan (BBB) locomotor scale. Histopathological changes of the injured spinal cord tissue and the number of neurons were evaluated after H.E. staining and Nissl staining. The expressions of Nestin, mitochondrial fusion-related protein optic atrophy-1 (OPA1) and NSC markers sex-determining region Y-box 2 (SOX2) in the injured spinal cord tissue were detected by immunofluorescence staining. The protein and mRNA expression levels of Nestin in the spinal cord tissue were detected by quantitative real-time PCR and Western blot, separately. RESULTS: Compared with the sham operation group, the BBB scores after modeling, and the number of neurons were significantly decreased (P<0.001), while the mean fluorescence intensity values of Nestin, SOX2 and OPA1, and the expressions of Nestin mRNA and protein considerably increased (P<0.001, P<0.01, P<0.05) in the model group. After EA intervention and in comparison with the model group, the BBB scores at the 7th and 14th day, the number of neurons, the mean fluorescence intensity values of Nestin, SOX2 and OPA1, and the expressions of Nestin mRNA and protein were strikingly increased (P<0.05, P<0.01, P<0.001) in the EA group. H.E. staining showed swollen, ruptured and necrotic neurons of the spinal cord, with a large number of vacuoles and severe inflammatory cell infiltration after modeling, which was relatively milder in the EA group. CONCLUSIONS: EA stimulation of GV14 and GV6 can promote the recovery of motor function in rats with SCI, which may be related to its effects in promoting mitochondrial fusion and enhancing the proliferation and differentiation of NSCs.

Involvement of NOTCH1-mediated Microglia Activation in Neuromodulation of Chronic Prostatitis-related Pain.

BACKGROUND/AIM: This study aimed to investigate the role of NOTCH receptor 1 (NOTCH1)-mediated activation of microglia in the L5-S2 spinal dorsal horn in chronic prostatitis pain. MATERIALS AND METHODS: Rats were divided into chronic prostatitis (CP) group and control group. Complete Freund's adjuvant was injected into the prostate, and prostate pathology and pain-related behavior were monitored to assess the successful establishment of the CP-related pain model. The dorsal horn of the L5-S2 spinal cord was collected for the detection of ionized calcium-binding adapter molecule 1 (IBA-1) and NOTCH1 expression by quantitative real time polymerase chain reaction and the detection of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) by enzyme-linked immunosorbent assay. Electrical excitability was assessed with whole-cell patch clamp. In addition, NOTCH1 receptor inhibitor or inhibitor of microglial cell activation was injected into the subarachnoid space, and the pro-inflammatory cytokines in the spinal cord were detected. RESULTS: In the CP group, the expression of NOTCH1, IBA-1, TNF-α and IL-1ß began to increase at 4 days, peaked at 12 days, and began to decline at 24 days, and it was significantly higher than in the control group (p<0.01). Inhibition of microglia or NOTCH1 receptor markedly reduced the content of TNF-α and IL-1ß in the spinal cord (p<0.05). At 4, 12 and 24 days, the amplitude and frequency of neuronal action potential increased and the threshold decreased markedly as compared to the control group (p<0.05), and spontaneous action potential was noted. CONCLUSION: NOTCH1 mediates the activation of microglia in the L5-S2 spinal cord, leading to the secretion of inflammatory factors and enhanced electrical excitability of neurons, which is related to persistent and refractory chronic prostatitis-related pain.

Electroacupuncture Alleviates Pain by Suppressing P2Y12R-Dependent Microglial Activation in Monoarthritic Rats.

Electroacupuncture (EA) effectively improves arthritis-induced hyperalgesia and allodynia by repressing spinal microglial activation, which plays a crucial role in pain hypersensitivity following tissue inflammation. However, the mechanism by which EA suppresses spinal microglial activation in monoarthritis (MA) remains unclear. In the present study, a rat model of MA was established through unilateral ankle intra-articular injection of complete Freund's adjuvant (CFA). The relationship among P2Y12 receptor (P2Y12R) expression, spinal microglial activation, and EA analgesia was investigated using quantitative real-time PCR (qRT‒PCR), western blotting, immunofluorescence (IF), and behavioral testing. The results found that EA treatment at the ipsilateral "Huantiao" (GB30) and "Yanglingquan" (GB34) acupoints markedly attenuated pain and spinal microglia M1 polarization in MA rats. In particular, P2Y12R expression was significantly increased at the mRNA and protein levels in the spinal dorsal horn in MA rats, whereas EA treatment effectively repressed the MA-induced upregulation of P2Y12R. IF analysis further revealed that most P2Y12R was expressed in microglia in the spinal dorsal horn. Pharmacological inhibition of P2Y12R by its antagonist (AR-C69931MX) decreased MA-induced spinal microglial activation and subsequent proinflammatory cytokine production. Consequently, AR-C69931MX significantly intensified the anti-pain hypersensitive function of EA in MA rats. Taken together, these results demonstrate that EA alleviates MA-induced pain by suppressing P2Y12R-dependent microglial activation.

The functional and anatomical characterization of three spinal output pathways of the anterolateral tract.

The nature of spinal output pathways that convey nociceptive information to the brain has been the subject of controversy. Here, we provide anatomical, molecular, and functional characterizations of two distinct anterolateral pathways: one, ascending in the lateral spinal cord, triggers nociceptive behaviors, and the other one, ascending in the ventral spinal cord, when inhibited, leads to sensorimotor deficits. Moreover, the lateral pathway consists of at least two subtypes. The first is a contralateral pathway that extends to the periaqueductal gray (PAG) and thalamus; the second is a bilateral pathway that projects to the bilateral parabrachial nucleus (PBN). Finally, we present evidence showing that activation of the contralateral pathway is sufficient for defensive behaviors such as running and freezing, whereas the bilateral pathway is sufficient for attending behaviors such as licking and guarding. This work offers insight into the complex organizational logic of the anterolateral system in the mouse.

Moxibustion ameliorates visceral hypersensitivity by regulating hypothalamus-spinal cord-colon axis in rats with irritable bowel syndrome with diarrhea. / 基于下丘脑-脊髓-ç»“è‚ è½´æŽ¢è®¨è‰¾ç¸æ”¹å–„è ¹æ³»åž‹è‚ æ˜“æ¿€ç»¼åˆå¾å¤§é¼ å† è„é«˜æ•æ„Ÿçš„ä½œç”¨æœºåˆ¶.

OBJECTIVES: To observe the effect of moxibustion intervention on the hypothalamus-spinal cord-colon axis of rats with irritable bowel syndrome with diarrhea (IBS-D) and explore the mechanism of moxibustion in improving visceral hypersensitivity in rats with IBS-D. METHODS: A total of 36 SD rats were randomly divided into normal, model, and moxibustion groups, with 12 rats in each group. The IBS-D model was established by maternal separation + acetic acid stimulation + chronic restraint. Rats of the moxibustion group received bilateral moxibustion on "Tianshu" (ST25) and "Shangjuxu" (ST37) for 15 min, once a day for 7 consecutive days. The body weight, loose stool rate, and minimum threshold volume of abdominal withdrawal reflex (AWR) were measured before and after moxibustion intervention, respectively. The histopathological changes in the colon tissue were observed after HE staining. The number of colonic mucosal mast cells (MCs) was measured by toluidine blue staining. The activation of MCs was determined by tryptase positive expression level and examined by immunohistochemical staining. The content, protein and mRNA expression levels and positive expression levels of corticotropin releasing factor (CRF), substance P (SP), and calcitonin gene-related peptide (CGRP) in the hypothalamus, spinal cord and colon tissues were measured by ELISA, Western blot, real-time fluorescent quantitative PCR and immunofluorescence staining, respectively. RESULTS: Compared with the normal group, the loose stool rate was increased (P<0.01)；the body weight and minimum threshold volume of AWR were decreased (P<0.01)；the inflammatory infiltration of colon tissues was obvious；the number of MCs and positive expression level of tryptase in the colon tissue were increased (P<0.01)；the contents, positive expression le-vels, protein and mRNA expression levels of CRF, SP and CGRP in the hypothalamus, spinal cord and colon tissues were increased (P<0.01, P<0.05) in the model group. After the intervention, compared with the model group, all these indicators showed opposite trends (P<0.01, P<0.05) in the moxibustion group. CONCLUSIONS: Moxibustion can improve visceral hypersensitivity in rats with IBS-D, and its mechanism may be related to regulating the hypothalamic-spinal-colon axis to reduce the release of CRF, SP and CGRP, and thus to inhibite MC in colon tissue.