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.

Eicosapentaenoic Acid Modulates Transient Receptor Potential V1 Expression in Specific Brain Areas in a Mouse Fibromyalgia Pain Model.

Pain is an unpleasant sensory and emotional experience accompanied by tissue injury. Often, an individual's experience can be influenced by different physiological, psychological, and social factors. Fibromyalgia, one of the most difficult-to-treat types of pain, is characterized by general muscle pain accompanied by obesity, fatigue, sleep, and memory and psychological concerns. Fibromyalgia increases nociceptive sensations via central sensitization in the brain and spinal cord level. We used intermittent cold stress to create a mouse fibromyalgia pain model via a von Frey test (day 0: 3.69 ± 0.14 g; day 5: 2.13 ± 0.12 g). Mechanical pain could be reversed by eicosapentaenoic acid (EPA) administration (day 0: 3.72 ± 0.14 g; day 5: 3.69 ± 0.13 g). A similar trend could also be observed for thermal hyperalgesia. The levels of elements in the transient receptor potential V1 (TRPV1) signaling pathway were increased in the ascending pain pathway, including the thalamus, medial prefrontal cortex, somatosensory cortex, anterior cingulate cortex, and cerebellum. EPA intake significantly attenuated this overexpression. A novel chemogenetics method was used to inhibit SSC and ACC activities, which presented an analgesic effect through the TRPV1 downstream pathway. The present results provide insights into the role of the TRPV1 signaling pathway for fibromyalgia and its potential as a clinical target.

Acupoint Catgut Embedding Diminishes Fibromyalgia Pain through TRPV1 in the Mouse Brain.

BACKGROUND: Chronic pain refers to pain that persists for over three months. Chronic pain may restrict activities of daily living, including work, learning, social life, and can lead to anxiety, depression, and sleep disturbance. Imaging data have demonstrated that central sensitization often occurs in the brain of patients with chronic pain, which arises from imbalanced neurotransmission in the central nervous system. Transient receptor potential vanilloid 1 (TRPV1) is an ion channel to serve as an inflammatory detector in the brain. We aim to determine the properties of acupoint catgut embedding (ACE) on cold stress-induced mice fibromyalgia (FM) and surveyed the character of TRPV1 and linked molecules in chronic FM pain. METHODS: Intermittent cold stress (ICS) was used to induce mice FM model. Mice were subgrouped into normal mice, ICS-induced FM group, FM mice with ACE, and FM in Trpv1-⁣/- group. ACE is a novel acupuncture technique that provides convenience and continuous nerve stimulation that has been reported effective on pain management. RESULTS: Our behavioral experiments showed similar levels of pain response among all groups before treatment. After ICS, prolonged mechanical and thermal pain was initiated (mechanical threshold: 1.96 ± 0.12 g; thermal latency: 4.86 ± 0.21 s) and were alleviated by ACE treatment and TRPV1 gene deletion. Inflammatory mediators were increased in the plasma of FM mice, while TRPV1 and related kinases were amplified in the hypothalamus and cerebellum. These changes were ameliorated in the ACE-treated and Trpv1-⁣/- groups. CONCLUSIONS: These novel findings suggest that chronic FM pain can be modulated by ACE or TRPV1 gene deletion. The analgesic effect of ACE through the TRPV1 pathway may reflect its potential as a therapeutic target for FM treatment.

NMDA receptors sustain but do not initiate neuronal depolarization in spreading depolarization.

Spreading depolarization (SD) represents a neurological process characterized by a massive, self-sustaining wave of brain cell depolarization. Understanding its mechanism is important for treating ischemic or hemorrhagic stroke and migraine with aura. Many believed that ion fluxes through NMDA receptors (NMDARs) are responsible for neuronal transmembrane currents of SD. However, the explicit role of NMDARs remains ambiguous. This is in part due to the limitation of traditional pharmacological approaches in resolving the contribution of NMDARs in different intercellular and intracellular processes of SD. Here, we applied single-cell blockade and genetic deletion methods to remove functional NMDARs from individual hippocampal CA1 neurons in order to examine the role of NMDARs in the depolarization mechanism without affecting the propagation of SD. We analyzed neuronal membrane potential changes to demonstrate that NMDARs are not required for initiating the depolarization. Consistently, neuronal input resistance (RN) revealed a sharp decline at the start of SD, which was unaffected by blocking NMDARs. Instead, the recovery of both membrane potential and RN during the late phase of SD was facilitated by inhibition of NMDARs, indicating that NMDARs are responsible for sustaining the depolarization. Our results strongly indicate that NMDAR activation is not a determinant of the initiation of depolarization but is important for sustaining transmembrane ion fluxes during SD.

Electroacupuncture Reduced Fibromyalgia-Pain-like Behavior through Inactivating Transient Receptor Potential V1 and Interleukin-17 in Intermittent Cold Stress Mice Model.

Fibromyalgia (FM) is a widespread musculoskeletal pain associated with psychological disturbances, the etiopathogenesis of which is still not clear. One hypothesis implicates inflammatory cytokines in increasing central and peripheral sensitization along with neuroinflammation, leading to an elevation in pro-inflammatory cytokines, e.g., interleukin-17A (IL-17A), enhanced in FM patients and animal models. The intermittent cold stress (ICS)-induced FM-like model in C57BL/6 mice has been developed since 2008 and proved to have features which mimic the clinical pattern in FM patients such as mechanical allodynia, hyperalgesia, and female predominance of pain. Electroacupuncture (EA) is an effective treatment for relieving pain in FM patients, but its mechanism is not totally clear. It was reported as attenuating pain-like behaviors in the ICS mice model through the transient receptor potential vanilloid 1 (TRPV1) pathway. Limited information indicates that TRPV1-positive neurons trigger IL-17A-mediated inflammation. Therefore, we hypothesized that the IL-17A would be inactivated by EA and TRPV1 deletion in the ICS-induced FM-like model in mice. We distributed mice into a control (CON) group, ICS-induced FM model (FM) group, FM model with EA treatment (EA) group, FM model with sham EA treatment (Sham) group, and TRPV1 gene deletion (Trpv1-/-) group. In the result, ICS-induced mechanical and thermal hyperalgesia increased pro-inflammatory cytokines including IL-6, IL-17, TNFα, and IFNγ in the plasma, as well as TRPV1, IL-17RA, pPI3K, pAkt, pERK, pp38, pJNK, and NF-κB in the somatosensory cortex (SSC) and cerebellum (CB) lobes V, VI, and VII. Moreover, EA and Trpv1-/- but not sham EA countered these effects significantly. The molecular mechanism may involve the pro-inflammatory cytokines, including IL-6, IL-17, TNFα, and IFNγ. IL-17A-IL-17RA play a crucial role in peripheral and central sensitization as well as neuroinflammation and cannot be activated without TRPV1 in the ICS mice model. EA alleviated FM-pain-like behaviors, possibly by abolishing the TRPV1- and IL-17A-related pathways. It suggests that EA is an effective and potential therapeutic strategy in FM.

Continuous intrathecal saline infusion for treating refractory spontaneous intracranial hypotension: A case report.

Spontaneous intracranial hypotension (SIH) is a poorly understood condition that presents with a wide variety of symptoms, ranging from mild headaches to coma. It is typically caused by continuous spontaneous leakage of spinal cerebrospinal fluid (CSF), resulting in orthostatic headaches. However, the appropriate management of refractory SIH remains unclear. A 50-year-old man presented with orthostatic headache followed by a rapid decline in mental status. The imaging findings were consistent with the diagnosis of SIH, with bilateral cerebral subdural hematomas and abnormal fluid collection in the posterior epidural space from the T2 to T12 levels. Computed tomography myelography of the whole spine revealed multiple high-flow CSF leakages at the T6 to T8 levels. Despite treatment with bilateral burr hole drainage for subdural hematomas and repeated lumbar epidural blood patch (EBP) three times, the patient's condition worsened and he developed stupor. A lumbar intrathecal saline bolus (90 ml) was administered to restore CSF depletion. The patient's verbal function improved immediately, and continuous intrathecal saline infusion was administered at a rate of 10 ml/h for two days. The patient's stupor gradually resolved, and after his symptoms improved, the EBP injection was repeated at the T8 level. The patient recovered completely, and during the six-year follow-up, there were no signs of recurrence. SIH may cause a refractory decline in mental status, and lumbar intrathecal saline infusion may help arrest or reverse an impending central (transtentorial) herniation. This case demonstrates an appropriate bolus and continuous infusion of normal saline, and documents the resolution of SIH. This maneuver may change the CSF flow pattern and aims to seal the CSF fistula. Further studies are needed to better understand the mechanism of intrathecal saline infusion and establish effective treatment strategies for refractory cases of SIH.

Electroacupuncture Reduces Fibromyalgia Pain by Attenuating the HMGB1, S100B, and TRPV1 Signalling Pathways in the Mouse Brain.

Fibromyalgia is characterized by chronic and persistent widespread pain and generalized muscle tenderness, and it is refractory to treatment. The central nervous system (CNS) plays an important role, pain signalling, in fibromyalgia subjects. Electroacupuncture (EA) has been practiced for thousand years to treat many diseases that involve pain. We established fibromyalgia-like pain in mice using intermittent cold stress and investigated therapeutic effects and modes of action with EA. EA of 2 Hz and 1 mA was performed for 20 min at the ST36 acupoint in mice from Day 3 to Day 5. Our results showed that mechanical and thermal hyperalgesia were induced by intermittent cold stress (Day 5: mechanical: 1.43 ± 0.34 g; thermal: 3.98 ± 0.73 s) and were subsequently reversed by EA (Day 5: mechanical: 4.62 ± 0.48 g; thermal: 7.68 ± 0.68 s) or Trpv1 -/- (Day 5: mechanical: 4.38 ± 0.51 g; thermal: 7.48 ± 0.98 s). Activity in the HMGB1, S100B, and TRPV1 pathways was increased in the mouse prefrontal cortex, somatosensory cortex, thalamus, and amygdala with the stress treatment. This increase was attenuated by EA or Trpv1 -/-. These results suggest potential targets for the treatment of TRPV1-dependant fibromyalgia pain.

Optogenetic modulation of electroacupuncture analgesia in a mouse inflammatory pain model.

Peripheral tissue damage and associated inflammation can trigger neuroplastic changes in somatic pain pathways, such as reduced neuronal firing thresholds and synaptic potentiation, that ultimately lead to peripheral sensitization and chronic pain. Electroacupuncture (EA) can relieve chronic inflammatory pain, but the underlying mechanisms are unknown, including the contributions of higher pain centers such as somatosensory cortex (SSC). We investigated these mechanisms using optogenetic modulation of SSC activity in a mouse inflammatory pain model. Injection of Complete Freund's Adjuvant into the hind paw reliably induced inflammation accompanied by reduced mechanical and thermal pain thresholds (hyperalgesia) within three days (mechanical: 1.54 ± 0.13 g; thermal: 3.94 ± 0.43 s). Application of EA produced significant thermal and mechanical analgesia, but these responses were reversed by optogenetic activation of SSC neurons, suggesting that EA-induced analgesia involves modulation of central pain pathways. Western blot and immunostaining revealed that EA also attenuated CaMKIIα signaling in the dorsal root ganglion, central spinal cord, SSC, and anterior cingulate cortex (ACC). In contrast, optogenetic activation of the SSC induced CaMKIIα signaling in SSC and ACC. These findings suggest that AE can relieve inflammatory pain by suppressing CaMKIIα-dependent plasticity in cortical pain pathways. The SSC and ACC CaMKIIα signaling pathways may be valuable therapeutic targets for chronic inflammatory pain treatment.

Paper-Based Detection Device for Microenvironment Examination: Measuring Neurotransmitters and Cytokines in the Mice Acupoint.

(1) Background: The medical practice of acupuncture involves the insertion of a specialized stainless needle into a specific body point, often called an acupoint, to initiate a perceived phenomenon of de-qi sensation. Therefore, the term "de-qi" describes bodily sensations experienced by the recipient during acupuncture, which may include feelings of soreness, heaviness, fullness, numbness, and migration. However, while acupuncture treatments reportedly result in acupoint activation and an increased release of neurotransmitters or cytokines, detecting these substances released into the acupoint microenvironment is often missed or delayed in clinical and basic practice. (2) Methods: To address this situation, we employed a paper-based enzyme-linked immunosorbent assay method to examine acupoint environmental changes using minute volumes of easily accessible acupoint fluids. (3) Results: Our results indicated that while levels of adenosine triphosphate (ATP), interleukin-1ß, interleukin-6, glutamate, substance P, and histamine were all increased in the experimental group following electroacupuncture (EA) treatment, contrary results were observed in the sham EA and transient receptor potential vanilloid 1 (Trpv1-/-) groups. Subsequently, TRPV1 and its associated molecules were augmented in mouse dorsal root ganglion, spinal cord, thalamus, and the somatosensory cortex, then examined by Western blotting and immunofluorescence techniques. Investigations revealed that these elevations were still unobserved in the sham EA or EA in the Trpv1-/- groups. Furthermore, results showed that while administering ATP could mimic EA function, it could be reversed by the ATP P2 receptor antagonist, suramin. (4) Conclusions: Our data provide novel information, indicating that changes in neurotransmitter and cytokine levels can offer insight into acupuncture mechanisms and clinical targeting.

Associations between Zygoma Fracture and Post-Traumatic Headache: A Study among Taiwanese Population.

Few studies have discussed the development of post-traumatic headache (PTH) after zygoma fracture. This research aimed to examine the association between zygoma fracture and PTH and its other associated factors. A total of 3043 patients with zygoma fracture and 3043 patients with non-fracture were included in this analysis. They were matched to a non-fracture cohort from the National Health Insurance database according to age, sex, and index year. The incidence of PTH and its association with zygoma fracture were assessed. The zygoma fracture cohort had a significantly higher cumulative incidence of PTH than the non-fracture cohort in a 10-year follow-up. The confounding risk factors of PTH included zygoma fracture, female sex, and comorbidities, including obesity and depression. Female patients under 40 years old who had zygoma fractures had a higher incidence of PTH than the non-fracture group. Moreover, patients with zygoma fractures commonly developed PTH within three months after injury. Female patients under 40 years old with precedent zygoma fractures had a higher incidence rate of PTH than those without fractures. Moreover, patients with zygoma fractures commonly developed PTH within three months after injury. Nevertheless, before widely applying our results, a prospective study must be conducted to verify the risk factors found in this study.

Primary Leptomeningeal PNETs Mimicking TB Meningitis: A Case Report and Literature Review.

Primitive neuroectodermal tumors (PNETs) are easily detected, and the diagnosis made by neuroradiologic imaging. Leptomeningeal seeding is a common complication and carries a poor prognosis. Primary leptomeningeal PNETs are rarer and difficult to diagnose on magnetic resonance imaging (MRI) or cerebrospinal fluid (CSF) studies. We encountered a rare case of primary leptomeningeal primitive neuroectodermal tumor without intracranial mass lesion which was diagnosed by spinal lesion biopsy. This 25-year-old woman presented with worsening headaches and progressive visual impairment.The initial diagnosis was tubercle bacillus (TB) meningitis, and the final diagnosis of primary leptomeningeal PNET was made by spinal biopsy. We present this illustrative case, review previous cases in the literature, and suggest that diagnosis is considered in mildly affected patients with similar symptoms.

Effects of anti-epileptic drugs on spreading depolarization-induced epileptiform activity in mouse hippocampal slices.

Epilepsy and spreading depolarization (SD) are both episodic brain disorders and often exist together in the same individual. In CA1 pyramidal neurons of mouse hippocampal slices, induction of SD evoked epileptiform activities, including the ictal-like bursts, which occurred during the repolarizing phase of SD, and the subsequent generation of paroxysmal depolarization shifts (PDSs), which are characterized by mild depolarization plateau with overriding spikes. The duration of the ictal-like activity was correlated with both the recovery time and the depolarization potential of SD, whereas the parameters of PDSs were not significantly correlated with the parameters of SD. Moreover, we systematically evaluated the effects of multiple anti-epileptic drugs (AEDs) on SD-induced epileptiform activity. Among the drugs that are known to inhibit voltage-gated sodium channels, carbamazepine, phenytoin, valproate, lamotrigine, and zonisamide reduced the frequency of PDSs and the overriding firing bursts in 20-25 min after the induction of SD. The GABA uptake inhibitor tiagabine exhibited moderate effects and partially limited the incidence of PDSs after SD. AEDs including gabapentin, levetiracetam, ethosuximide, felbamate, and vigabatrin, had no significant effect on SD-induced epileptic activity. Taken together, these results demonstrate the effects of AEDs on SD and the related epileptiform activity at the cellular level.

Multifocal osteolytic lesions of the skull: a primary cavernous hemangioma mimicking a neoplastic invasive lesion.

Intraosseous cavernous hemangioma is a rare cause of osteolytic lesions of the skull, and its multifocal type is even more infrequent. This tumor is difficult to accurately diagnose by imaging and can be confused with osteolytic Langerhan's cell histiocytosis or other neoplasms. Here we present a case of multifocal intraosseous cavernous hemangioma of the skull treated with surgical intervention in our hospital five years ago. A review of related literatures and case reports is also provided to help clarify the diagnosis and devise treatment regimens. In light of the difficulties of early diagnosis, early en bloc surgical removal is recommended.

Embolization followed by surgery for treatment of perimedullary arteriovenous fistula causing acute myelopathy.

BACKGROUND: Perimedullary arteriovenous fistula (AVF) is rare. There are three subtypes, and the treatment strategies for each are different. Subtype B (multiple fistulas) can be treated by either embolization or surgery. On the basis of a case from our treatment experience, we propose a method for achieving optimal outcome while minimizing nerve injury. CASE DESCRIPTION: A 51-year-old female was admitted to our hospital with acute myelopathy caused by a perimedullary AVF. Initially, we treated her by embolization using the chemical agent Onyx. Her symptoms improved immediately but gradually returned beginning 1 week later. Two months later, the symptoms had returned to pretreatment status, so we removed the fistulas surgically. Severe adhesions between nerve and occult venous varices were noted during the operation. Afterward, the patient's symptoms improved significantly. Histopathological sections showed an inflammatory reaction around the varices. CONCLUSIONS: We initially considered several possible reasons for the return of symptoms: (a) Hypoperfusion of the spinal cord; (b) mass effect of the occult vein varices; (c) residual AVF or vascular remodeling resulting in recurrent cord hypertension; (d) Onyx-induced perivascular inflammation resulting in nerves adhering to each other and to occult venous varices. Clinical, surgical, and pathological findings ruled out the first three, leaving Onyx-induced perivascular inflammation as the probable reason. Given our treatment experience and the pros and cons of the two methods, we propose that initial embolization followed by surgery after 5 days to remove occult venous varices is the ideal strategy for treating perimedullary AVF of subtype B.