scholarly journals Puerarin Alleviates Neuropathic Pain by Inhibiting Neuroinflammation in Spinal Cord

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Ming Liu ◽  
Kaijun Liao ◽  
Changxi Yu ◽  
Xuejun Li ◽  
Suhuan Liu ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Spinal Dorsal Horn ◽  
Chronic Constriction Injury ◽  
Intrathecal Administration ◽  
Nociceptive Response ◽  
Nuclear Factor ◽  
Spinal Dorsal ◽  
Drug Treatments ◽  
Anti Inflammation

Neuropathic pain responds poorly to drug treatments, and partial relief is achieved in only about half of the patients. Puerarin, the main constituent ofPuerariae Lobatae Radix, has been used extensively in China to treat hypertension and tumor. The current study examined the effects of puerarin on neuropathic pain using two most commonly used animal models: chronic constriction injury (CCI) and diabetic neuropathy. We found that consecutive intrathecal administration of puerarin (4–100 nM) for 7 days inhibited the mechanical and thermal nociceptive response induced by CCI and diabetes without interfering with the normal pain response. Meanwhile, in both models puerarin inhibited the activation of microglia and astroglia in the spinal dorsal horn. Puerarin also reduced the upregulated levels of nuclear factor-κB (NF-κB) and other proinflammatory cytokines, such as IL-6, IL-1β, and TNF-α, in the spinal cord. In summary, puerarin alleviated CCI- and diabetes-induced neuropathic pain, and its effectiveness might be due to the inhibition of neuroinflammation in the spinal cord. The anti-inflammation effect of puerarin might be related to the suppression of spinal NF-κB activation and/or cytokines upregulation. We conclude that puerarin has a significant effect on alleviating neuropathic pain and thus may serve as a therapeutic approach for neuropathic pain.

scholarly journals A systematic review on descending serotonergic projections and modulation of spinal nociception in chronic neuropathic pain and after spinal cord stimulation

2021 ◽  
Vol 17 ◽  
pp. 174480692110439
Author(s):  
Lonne Heijmans ◽  
Martijn R Mons ◽  
Elbert A Joosten
Keyword(s):  
Systematic Review ◽  
Spinal Cord ◽  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Serotonergic System ◽  
Chronic Neuropathic Pain ◽  
Spinal Dorsal ◽  
Important Target ◽  
Serotonergic Modulation

Chronic neuropathic pain is a debilitating ordeal for patients worldwide and pharmacological treatment efficacy is still limited. As many pharmacological interventions for neuropathic pain often fail, insights into the underlying mechanism and role of identified receptors is of utmost importance. An important target for improving treatment of neuropathic pain is the descending serotonergic system as these projections modulate nociceptive signaling in the dorsal horn. Also with use of last resort treatments like spinal cord stimulation (SCS), the descending serotonergic projections are known to be involved in the pain relieving effect. This systematic review summarizes the involvement of the serotonergic system on nociceptive modulation in the healthy adult rodent and the chronic neuropathic rodent and summarizes all available literature on the serotonergic system in the SCS-treated neuropathic rodent. Medline, Embase and Pubmed databases were used in the search for articles. Descending serotonergic modulation of nociceptive signaling in spinal dorsal horn in normal adult rat is mainly inhibitory and mediated by 5-HT1a, 5-HT1b, 5-HT2c, 5-HT3 and 5-HT4 receptors. Upon injury and in the neuropathic rat, this descending serotonergic modulation becomes facilitatory via activation of the 5-HT2a, 5-HT2b and 5-HT3 receptors. Analgesia due to neuromodulatory intervention like SCS restores the inhibitory function of the descending serotonergic system and involves 5-HT2, 5-HT3 and 5-HT4 receptors. The results of this systematic review provide insights and suggestions for further pharmacological and or neuromodulatory treatment of neuropathic pain based on targeting selected serotonergic receptors related to descending modulation of nociceptive signaling in spinal dorsal horn. With the novel developed SCS paradigms, the descending serotonergic system will be an important target for mechanism-based stimulation induced analgesia.

scholarly journals Resveratrol Mediates Mechanical Allodynia Through Modulating Inflammatory Response via the TREM2-autophagy Axis in SNI Rat Model

2020 ◽  
Author(s):  
Yaping Wang ◽  
Yu Shi ◽  
Yongquan Huang ◽  
Wei Liu ◽  
Guiyuan Cai ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Inflammatory Response ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Rat Model ◽  
Mechanical Allodynia ◽  
Spinal Dorsal Horn ◽  
Intrathecal Administration ◽  
Spared Nerve Injury ◽  
Spinal Dorsal

Abstract Background Neuropathic pain (NeuP) is a chronic and challenging clinical problem, with little effective treatment. Resveratrol has shown neuroprotection by inhibiting inflammatory response in NeuP. Recently, the triggering receptor expressed on myeloid cells 2 (TREM2) expressed by microglia was identified as a critical factor of inflammation in nervous system diseases. In this study, we explored whether resveratrol could ameliorate neuroinflammation and produce anti-mechanical allodynia effects via regulating TREM2 in spared nerve injury rats, as well as investigated the underlying mechanisms. Methods A spared nerve injury (SNI) rat model was performed to investigate whether resveratrol could exert anti-mechanism allodynia effects via inhibiting neuroinflammation. To evaluate the role of TREM2 in anti-neuroinflammatory function of resveratrol, Lentivirus coding TREM2 was intrathecal injected into SNI rats to activate TREM2 and the pain behavior was detected by the Von Frey test. Furthermore, 3-Methyladenine (3-MA, an autophagy inhibitor) was performed to analyze the molecular mechanisms of resveratrol-mediated anti-neuroinflammation using Western blot, qPCR, immunofluorescence. Results The TREM2 expression and number of the microglial cell was significantly increased in the ipsilateral spinal dorsal horn after SNI. We found that intrathecal administration of resveratrol (300ug/day) alleviated mechanical allodynia; obviously enhanced autophagy; and markedly reduced the levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the ipsilateral spinal dorsal horn after SNI. Moreover, the number of Iba-1+ microglial cells and TREM2 expression were downregulated after resveratrol treatment. Intrathecal administration of lentivirus coding TREM2 and/or 3-methyladenine in those rats induced deficiencies in resveratrol-mediated anti-inflammation, leading to mechanical allodynia that could be rescued via administration of Res. Furthermore, 3-MA treatment contributed to TREM2-mediated mechanical allodynia. Conclusions Taken together, these data reveal that resveratrol relieves neuropathic pain through suppressing microglia-mediated neuroinflammation via regulating the TREM2-autophagy axis in SNI rats.

scholarly journals Evans Blue Reduces Neuropathic Pain Behavior by Inhibiting Spinal ATP Release

2019 ◽  
Vol 20 (18) ◽  
pp. 4443 ◽  
Author(s):  
Yin ◽  
Hong ◽  
Phạm ◽  
Shin ◽  
Gwon ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Evans Blue ◽  
Spinal Dorsal Horn ◽  
Critical Role ◽  
Atp Release ◽  
Pain Behavior ◽  
Dependent Manner ◽  
Spinal Dorsal

Upon peripheral nerve injury, vesicular ATP is released from damaged primary afferent neurons. This extracellular ATP subsequently activates purinergic receptors of the spinal cord, which play a critical role in neuropathic pain. As an inhibitor of the vesicular nucleotide transporter (VNUT), Evans blue (EB) inhibits the vesicular storage and release of ATP in neurons. Thus, we tested whether EB could attenuate neuropathic pain behavior induced by spinal nerve ligation (SNL) in rats by targeting VNUT. An intrathecal injection of EB efficiently attenuated mechanical allodynia for five days in a dose-dependent manner and enhanced locomotive activity in an SNL rat model. Immunohistochemical analysis showed that EB was found in VNUT immunoreactivity on neurons in the dorsal root ganglion and the spinal dorsal horn. The level of ATP in cerebrospinal fluid in rats with SNL-induced neuropathic pain decreased upon administration of EB. Interestingly, EB blocked ATP release from neurons, but not glial cells in vitro. Eventually, the loss of ATP decreased microglial activity in the ipsilateral dorsal horn of the spinal cord, followed by a reduction in reactive oxygen species and proinflammatory mediators, such as interleukin (IL)-1β and IL-6. Finally, a similar analgesic effect of EB was demonstrated in rats with monoiodoacetate-induced osteoarthritis (OA) pain. Taken together, these data demonstrate that EB prevents ATP release in the spinal dorsal horn and reduces the ATP/purinergic receptor-induced activation of spinal microglia followed by a decline in algogenic substances, thereby relieving neuropathic pain in rats with SNL.

scholarly journals Resveratrol mediates mechanical allodynia through modulating inflammatory response via the TREM2-autophagy axis in SNI rat model

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Yaping Wang ◽  
Yu Shi ◽  
Yongquan Huang ◽  
Wei Liu ◽  
Guiyuan Cai ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Inflammatory Response ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Rat Model ◽  
Mechanical Allodynia ◽  
Spinal Dorsal Horn ◽  
Intrathecal Administration ◽  
Spared Nerve Injury ◽  
Spinal Dorsal

Abstract Background Neuropathic pain (NeuP) is a chronic and challenging clinical problem, with little effective treatment. Resveratrol has shown neuroprotection by inhibiting inflammatory response in NeuP. Recently, the triggering receptor expressed on myeloid cells 2 (TREM2) expressed by microglia was identified as a critical factor of inflammation in nervous system diseases. In this study, we explored whether resveratrol could ameliorate neuroinflammation and produce anti-mechanical allodynia effects via regulating TREM2 in spared nerve injury rats, as well as investigated the underlying mechanisms. Methods A spared nerve injury (SNI) rat model was performed to investigate whether resveratrol could exert anti-mechanical allodynia effects via inhibiting neuroinflammation. To evaluate the role of TREM2 in anti-neuroinflammatory function of resveratrol, lentivirus coding TREM2 was intrathecally injected into SNI rats to activate TREM2, and the pain behavior was detected by the von Frey test. Furthermore, 3-methyladenine (3-MA, an autophagy inhibitor) was applied to study the molecular mechanisms of resveratrol-mediated anti-neuroinflammation using Western blot, qPCR, and immunofluorescence. Results The TREM2 expression and number of the microglial cells were significantly increased in the ipsilateral spinal dorsal horn after SNI. We found that intrathecal administration of resveratrol (300ug/day) alleviated mechanical allodynia; obviously enhanced autophagy; and markedly reduced the levels of interleukin-1β, interleukin-6, and tumor necrosis factor-α in the ipsilateral spinal dorsal horn after SNI. Moreover, the number of Iba-1+ microglial cells and TREM2 expression were downregulated after resveratrol treatment. Intrathecal administration of lentivirus coding TREM2 and/or 3-MA in those rats induced deficiencies in resveratrol-mediated anti-inflammation, leading to mechanical allodynia that could be rescued via administration of Res. Furthermore, 3-MA treatment contributed to TREM2-mediated mechanical allodynia. Conclusions Taken together, these data reveal that resveratrol relieves neuropathic pain through suppressing microglia-mediated neuroinflammation via regulating the TREM2-autophagy axis in SNI rats.

scholarly journals Yokukansan Improves Mechanical Allodynia through the Regulation of Interleukin-6 Expression in the Spinal Cord in Mice with Neuropathic Pain

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Shigeru Ebisawa ◽  
Tsugunobu Andoh ◽  
Yutaka Shimada ◽  
Yasushi Kuraishi
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Herbal Medicine ◽  
Sciatic Nerve ◽  
Pain Control ◽  
Mechanical Allodynia ◽  
Spinal Dorsal Horn ◽  
Herbal Medicines ◽  
Spinal Dorsal ◽  
Partial Sciatic Nerve Ligation

Neuropathic pain is caused by nerve injury. Yokukansan (Yi-Gan San), a traditional Japanese (Kampo) medicine, has been widely used for neuropathic pain control. However, the analgesic mechanisms remain unknown. In this study, we investigated the analgesic mechanisms of yokukansan in a mouse model of neuropathic pain. Partial sciatic nerve ligation (PSL) induced mechanical allodynia in mice. Repetitive oral administration of the extracts of yokukansan and the constituent herbal medicine Atractylodis Lanceae Rhizoma, but not Glycyrrhizae Radix, relieved mechanical allodynia in the PSL mice and inhibited the PSL-induced expression of interleukin- (IL-) 6 mRNA in the spinal cord. Yokukansan did not attenuate intrathecal IL-6-induced mechanical allodynia. IL-6 immunoreactivity was detected in microglia and astrocytes in the spinal dorsal horn. These results suggest that yokukansan relieves mechanical allodynia in PSL mice by regulating the expression of IL-6 in astrocytes and/or microglia in the spinal cord. In addition, the components of Atractylodis Lanceae Rhizoma, one of the constituent herbal medicines in yokukansan, may play an important role in the regulation of IL-6 expression and neuropathic pain control.

scholarly journals Effects of ghrelin on pGSK-3β and β-catenin expression when protects against neuropathic pain behavior in rats challenged with chronic constriction injury

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhiyou Peng ◽  
Leiqiong Zha ◽  
Meijuan Yang ◽  
Yunze Li ◽  
Xuejiao Guo ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Tumor Necrosis ◽  
Chronic Constriction Injury ◽  
Immunohistochemical Analysis ◽  
Spinal Dorsal ◽  
Gsk 3Β ◽  
Factor Α ◽  
Necrosis Factor

Abstract Ghrelin has been shown to alleviate neuropathic pain by inhibiting the release of proinflammatory cytokines. The purpose of this study was to investigate the role of GSK-3β/β-catenin signaling in mediating the effect of ghrelin on neuropathic pain and to understand the associated mechanisms. Chronic constriction injury (CCI) of the sciatic nerve was used to establish a rat model of neuropathic pain. Hyperalgesia and allodynia were evaluated by observing the mechanical withdrawal threshold and the thermal withdrawal latency. Wnt3a and β-catenin protein expression and GSK-3β phosphorylation were detected by western blotting analysis. The levels of tumor necrosis factor-α and IL-1β were determined using an enzyme-linked immunosorbent assay. In addition, we used immunohistochemical analysis to determine the levels of GSK-3β phosphorylation in the dorsal horn of the spinal cord. Intrathecal delivery of ghrelin effectively ameliorated CCI-induced mechanical allodynia and thermal hyperalgesia at 7 and 14 days and reduced the levels of tumor necrosis factor-α. Ghrelin inhibited CCI-induced GSK-3β activation and β-catenin overexpression in the spinal dorsal horn. Moreover, intrathecal injection of ghrelin suppressed the activation of GSK-3β in the spinal dorsal horn of CCI rats, as assessed by immunohistochemical analysis. Our data indicated that ghrelin could markedly alleviate neuropathic pain by inhibiting the expression of β-catenin, via the suppression of GSK-3β activation, in the spinal cord of CCI rats.

scholarly journals Loss of calcineurin in the spinal dorsal horn contributes to neuropathic pain, and intrathecal administration of the phosphatase provides prolonged analgesia

Pain ◽  
2013 ◽  
Vol 154 (10) ◽  
pp. 2024-2033 ◽  
Author(s):  
Gordana Miletic ◽  
Jennifer A. Lippitt ◽  
Kristine M. Sullivan ◽  
Vjekoslav Miletic
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Intrathecal Administration ◽  
Spinal Dorsal

scholarly journals Sanguinarine Attenuates Neuropathic Pain in a Rat Model of Chronic Constriction Injury

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ping Li ◽  
Yan-Xiu Wang ◽  
Guang Yang ◽  
Zun-Cheng Zheng ◽  
Chao Yu
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
P38 Mapk ◽  
Spinal Dorsal Horn ◽  
Chronic Constriction Injury ◽  
Mapk Signaling ◽  
Dependent Manner ◽  
Withdrawal Threshold ◽  
Spinal Dorsal ◽  
Plant Medicine

Objective. There is still no effective treatment of neuropathic pain. Sanguinarine is a natural plant medicine with anti-inflammatory effects, but its effect on neuropathic pain remains unclear. This study was aimed at investigating the potential of sanguinarine to attenuate neuropathic pain. Methods. Neuropathic pain was induced by chronic constriction injury (CCI) of the sciatic nerve. Rats were randomly divided into several groups: sham, CCI, CCI+SG (1.00 mg/kg), CCI+SG (2.50 mg/kg), and CCI+SG (6.25 mg/kg). SG was injected intraperitoneally from the day of surgery every three days. The mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were recorded before surgery and on days 1, 3, 7, and 14 after surgery. The microglia in the spinal dorsal horn were examined by immunofluorescence. p38 MAPK expression in the spinal dorsal horn was detected by PCR and Western blot analysis. Cytokine levels in the spinal dorsal horn were measured by ELISA. Results. MWT and TWL were significantly reduced in the CCI group, but sanguinarine recovered MWT and TWL in the CCI group. In addition, sanguinarine inhibited the activation of microglia and decreased the expression of p-p38 and TNF-α, IL-1β, and IL-6 in the spinal dorsal horn of the CCI group in a dose-dependent manner. Conclusions. Our results suggest that sanguinarine can attenuate neuropathic pain via inhibiting the activation of microglia and the activation of the p38 MAPK signaling pathway.

scholarly journals Downregulation of Metallothionein-2 Contributes to Oxaliplatin-induced Neuropathic Pain

2020 ◽  
Author(s):  
Xuelin Huang ◽  
Jie Deng ◽  
Ting Xu ◽  
Wenjun Xin ◽  
Yuehong Zhang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Genetic Alterations ◽  
Mrna Levels ◽  
Spinal Cord Neurons ◽  
Spinal Dorsal ◽  
Dorsal Horns ◽  
Prevention And Treatment

Abstract Background We previously reported a correlation between small doses of oxaliplatin penetrating onto the spinal cord and acute pain after chemotherapy. Here we propose that MT2 within the spinal dorsal horns participates the development of oxaliplatin-induced neuropathic pain and may be a pharmacological target for the prevention and treatment of chemotherapy-induced peripheral neuropathy (CIPN). Methods The rat model of CIPN was established by a 5 consecutive injection of oxaliplatin (0.4 mg/ 100 g/ day). Genetic restoration or inhibition of neuron-specific metallothionein-2 was implemented 21 days before oxaliplatin treatment. Mechanical allodynia and locomotor activity were assayed. Cell-specific expression of metallothionein-2, the mRNA levels of pro-inflammatory cytokines, nuclear translocation of NF-κB, the protein levels of expression of IκB-α, and interaction between IκB-α and P65 were evaluated in the spinal dorsal horns. Also, in vitro interaction of sequentially deleted IκB-α promoter with metallothionein-2 was used to assess the signal transduction mechanism. Results We found that oxaliplatin induced downregulation of metallothionein-2 in rat spinal cord neurons. By contrast, genetic restoration of metallothionein-2 in the spinal dorsal horn neuron blocked and reversed neuropathic pain in oxaliplatin-treated rats of both sexes, whereas genetic inhibition of metallothionein-2 triggered neuropathic pain in normal rats. No locomotor impairment was observed after the genetic alterations of metallothionein-2. At the molecular level, metallothionein-2 modulated oxaliplatin-induced neuroinflammation, activation of NF-κB, and transcriptional expression of IκB-α promoter, and these processes could be blocked by genetic restoration of metallothionein-2 in the spinal dorsal horn neurons. Conclusions Metallothionein-2 is a potential target for the prevention and treatment of CIPN. A reduction of NF-κB activation and inflammatory responses by enhancing the transcription of IκB-α promoter is proposed in the mechanism.

scholarly journals Downregulation of metallothionein-2 contributes to oxaliplatin-induced neuropathic pain

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xuelin Huang ◽  
Jie Deng ◽  
Ting Xu ◽  
Wenjun Xin ◽  
Yuehong Zhang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neuropathic Pain ◽  
Locomotor Activity ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Genetic Alterations ◽  
Mrna Levels ◽  
Spinal Dorsal ◽  
Dorsal Horns ◽  
Prevention And Treatment

Abstract Background We previously reported a correlation between small doses of oxaliplatin penetrating onto the spinal cord and acute pain after chemotherapy. Here, we propose that MT2 within the spinal dorsal horns participates in the development of oxaliplatin-induced neuropathic pain and may be a pharmacological target for the prevention and treatment of chemotherapy-induced peripheral neuropathy (CIPN). Methods The rat model of CIPN was established by 5 consecutive injections of oxaliplatin (0.4 mg/100 g/day). Genetic restoration of neuron-specific metallothionein-2 was implemented 21 days before oxaliplatin treatment, and also, genetic inhibition by metallothionein-2 siRNA was performed. Mechanical allodynia and locomotor activity were assayed. Cell-specific expression of metallothionein-2, the mRNA levels of pro-inflammatory cytokines, nuclear translocation of NF-κB, the protein levels of expression of IκB-α, and interaction between IκB-α and P65 were evaluated in the spinal dorsal horns. Also, in vitro interaction of sequentially deleted IκB-α promoter with metallothionein-2 was used to assess the signal transduction mechanism. Results We found that oxaliplatin induced downregulation of metallothionein-2 in rat spinal cord neurons. By contrast, genetic restoration of metallothionein-2 in the spinal dorsal horn neuron blocked and reversed neuropathic pain in oxaliplatin-treated rats of both sexes, whereas genetic inhibition of metallothionein-2 triggered neuropathic pain in normal rats. Overall locomotor activity was not impaired after the genetic alterations of metallothionein-2. At the molecular level, metallothionein-2 modulated oxaliplatin-induced neuroinflammation, activation of NF-κB, and inactive transcriptional expression of IκB-α promoter, and these processes could be blocked by genetic restoration of metallothionein-2 in the spinal dorsal horn neurons. Conclusions Metallothionein-2 is a potential target for the prevention and treatment of CIPN. A reduction of NF-κB activation and inflammatory responses by enhancing the transcription of IκB-α promoter is proposed in the mechanism.

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