Articles: neuralgia.
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Following surgical repair after peripheral nerve injury, neuropathic pain diminishes in most patients but can persist in a small proportion of cases, the mechanism of which remains poorly understood. Based on the spared nerve injury (SNI), we developed a rat nerve repair (NR) model, where a delayed reconstruction of the SNI-injured nerves resulted in alleviating chronic pain-like behavior only in a subpopulation of rats. Multiple behavioral measures were assayed over 11-week presurgery and postsurgery periods (tactile allodynia, pain prick responses, sucrose preference, motor coordination, and cold allodynia) in SNI (n = 10), sham (n = 8), and NR (n = 12) rats. ⋯ By contrast, large brain functional connectivity differences were observed between NR groups, where corticolimbic reorganization paralleled with pain recovery (repeated-measures analysis of variance, false discovery rate, P < 0.05), and functional connectivity between accumbens and medial frontal cortex was related both to tactile allodynia (nociception) and to sucrose preference (anhedonia) in the NR group. Our study highlights the importance of brain circuitry in the reversal of neuropathic pain as a natural pain-relieving mechanism. Further studies regarding the therapeutic potentials of these processes are warranted.
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Anesthesia and analgesia · Oct 2022
Reactive Oxygen Species Contributes to Type 2 Diabetic Neuropathic Pain via the Thioredoxin-Interacting Protein-NOD-Like Receptor Protein 3-N-Methyl-D-Aspartic Acid Receptor 2B Pathway.
The number of patients with diabetic neuropathic pain (DNP) continues to increase, but available treatments are limited. This study aimed to examine the influence of reactive oxygen species (ROS)-thioredoxin-interacting protein (TXNIP)-NOD-like receptor protein 3 (NLRP3)- N -methyl-D-aspartic acid receptor 2B (NR2B) pathway on type 2 DNP. ⋯ Our findings suggest that spinal ROS can contribute to type 2 DNP through TXNIP-NLRP3-NR2B pathway.
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Animal and human studies have shown that exercise prior to nerve injury prevents later chronic pain, but the mechanisms of such preconditioning remain elusive. Given that exercise acutely increases the formation of free radicals, triggering antioxidant compensation, we hypothesized that voluntary running preconditioning would attenuate neuropathic pain by supporting redox homeostasis after sciatic nerve injury in male and female rats. We show that 6 weeks of voluntary wheel running suppresses neuropathic pain development induced by chronic constriction injury across both sexes. ⋯ The protective effects of prior voluntary wheel running were mediated by Nrf2, as suppression was abolished across both sexes when Nrf2 activation was blocked during the 6-week running phase. This study provides insight into the mechanisms by which physical activity may prevent neuropathic pain. Preconditioning by voluntary wheel running, terminated prior to nerve injury, suppresses later neuropathic pain in both sexes, and it is modulated through the activation of Nrf2-antioxidant signaling.
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Randomized Controlled Trial
Exercise Facilitates the M1-to-M2 Polarization of Microglia by Enhancing Autophagy via the BDNF/AKT/mTOR Pathway in Neuropathic Pain.
In neuropathic pain following peripheral nerve injury, microglia are rapidly activated and accumulated in the spinal cord. Physical exercise can alleviate neuropathic pain. However, the exact mechanism underlying this analgesic effect is not fully understood. ⋯ Exercise training promoted the recovery of sciatic nerve injury in mice, possibly by regulating microglial polarization through BDNF/AKT/mTOR signaling-mediated autophagy flux. We confirmed the efficacy of exercise training in alleviating neuropathic pain and suggest a new therapeutic target for neuropathic pain.
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J Pain Symptom Manage · Oct 2022
Review Meta AnalysisCan noninvasive brain stimulation improve pain and depressive symptoms in patients with neuropathic pain? A systematic review and meta-analysis.
Noninvasive brain stimulations (NIBS) have been increasingly applied to the patients with neuropathic pain (NP), while the effectiveness of NIBS in the management of NP is still conflicting. ⋯ This meta-analysis revealed the analgesic effect of NIBS on patients with NP, while no beneficial effect was observed on reducing concomitant depression symptoms. The findings recommended the clinical application of NIBS in patients with NP.