SIRT1 Mediates Neuropathic Pain Induced by Sciatic Nerve Chronic Constrictive Injury in the VTA-NAc Pathway

Background. Mounting evidence has shown that sirtuin 1 (SIRT1), a class III histone deacetylase, alleviated several types of neuropathic pain in the spinal cord and dorsal root ganglion and regulated some aberrant behaviors in the ventral tegmental area (VTA) and the nucleus accumbens (NAc). Methods. In this context, the effect of SIRT1 on neuropathic pain in the VTA-NAc pathway was investigated in the model of chronic constrictive injury (CCI). Results. SIRT1 was localized in the VTA neurons in naive mice. The expression of SIRT1 was decreased in the contralateral VTA of CCI mice. After microinjection of SRT1720 (an activator of SIRT1) in the contralateral VTA of CCI mice, the established thermal hyperalgesia was attenuated. However, it was further exacerbated by EX-527 (an inhibitor of SIRT1). The elevated level of acetyl-histone 3 was reduced by SRT1720 but further elevated by EX-527 in the contralateral VTA of CCI mice. The increased expression of Fos in both VTA and NAc was downregulated by SRT1720 but further upregulated by EX-527 in CCI mice. Conclusions. The discovery of the effect of SIRT1 on neuropathic pain in the VTA represents an important step forward in understanding the analgesic mechanisms of the VTA-NAc pathway.

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Intrathecal Injection of Dual Zipper Kinase shRNA Alleviating the Neuropathic Pain in a Chronic Constrictive Nerve Injury Model

International Journal of Molecular Sciences ◽

10.3390/ijms19082421 ◽

2018 ◽

Vol 19 (8) ◽

pp. 2421 ◽

Cited By ~ 1

Author(s):

Meei-Ling Sheu ◽

Chien-Yi Chiang ◽

Hong-Lin Su ◽

Chun-Jung Chen ◽

Jason Sheehan ◽

...

Keyword(s):

Neuropathic Pain ◽

Dorsal Root Ganglion ◽

Dorsal Root ◽

Leucine Zipper ◽

Ganglion Cells ◽

Neuronal Degeneration ◽

Intrathecal Injection ◽

Thermal Hyperalgesia ◽

Mitogen Activated Protein Kinase ◽

Chronic Constrictive Injury

Dual leucine zipper kinase (DLK) is a member of mitogen-activated protein kinase kinase kinase (MAP3K) family mainly involved in neuronal degeneration. However, the role of DLK signaling in the neuropathic pain has not yet been fully determined. Chronic constrictive injury (CCI) was conducted by four 3-0 chromic gut ligatures loosely ligated around the sciatic nerve. Escalated DLK expression over the dorsal root ganglion was observed from one to four rings of CCI. Remarkable expression of DLK was observed in primary dorsal root ganglion cells culture subjected to electrical stimulation and attenuated by DLK short hairpin RNA (shRNA) treatment. Intrathecal injection of DLK shRNA attenuates the expression of DLK over the dorsal root ganglion and hippocampus neurons and increased the threshold of mechanical allodynia and decreased thermal hyperalgesia. In CatWalk gait analysis, significant decreases of print area, maximum contact maximum intensity, stand phase, single stance, and regular index by CCI were alleviated by the DLK shRNA administration. In conclusion, the expression of DLK was up-regulated in chronic constrictive injury and attenuated by the administration of DLK shRNA, which paralleled the improvement of neurobehavior of neuropathic pain. The modulation of DLK expression is a potential clinic treatment option for neuropathic pain.

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Conditioned medium from the stem cells of human exfoliated deciduous teeth ameliorates neuropathic pain in a partial sciatic nerve ligation model

10.21203/rs.3.rs-279355/v1 ◽

2021 ◽

Author(s):

Yao Liu ◽

Fumiya Kano ◽

Noboru Hashimoto ◽

Linze Xia ◽

Hideharu Hibi ◽

...

Keyword(s):

Spinal Cord ◽

Stem Cells ◽

Neuropathic Pain ◽

Sciatic Nerve ◽

Dental Pulp ◽

Dorsal Root ◽

Antinociceptive Effect ◽

Deciduous Teeth ◽

M2 Macrophages ◽

Partial Sciatic Nerve Ligation

Abstract BackgroundAlthough recent studies have revealed the powerful antinociceptive effect of human dental pulp stem cells in an animal model for diabetes and osteoarthritis, its analgesic mechanisms are still largely elusive. We have previously reported that conditioned medium (CM) from dental pulp stem cells of deciduous teeth (SHED-CM) or its components, monocyte chemoattractant protein-1 (MCP-1) and the secreted ectodomain of sialic acid-binding Ig-like lectin-9 (sSiglec-9), directly induces anti-inflammatory M2 macrophages, however the antinociceptive activity of induced M2 is unknown. In this study, we investigated the antinociceptive effect of SHED-CM, MCP-1, and sSiglec-9 or secretome from M2-induced by SHED-CM (M2-CM) against neuropathic pain (NP) using a partial sciatic nerve ligation (PSL) mouse model and analyzed the mechanical bases of their antinociceptive effects. MethodsPSL mice were treated using SHED-CM with or without mannosylated-Clodrosome, specifically depleting M2 macrophages, recombinant MCP-1 and sSiglec-9 protein, M2-CM, or fibroblast-CM. Human Schwann cells activated by TNF-α in vitro were treated with M2-CM. The expression of pro-inflammatory mediators, neuroprotective factors, the nociceptive receptor, and markers for M1, M2, and activated glial cells in injured sciatic nerve (SCN), dorsal root ganglion, or spinal cord were evaluated by RT-PCR and immunohistochemistry. Mechanical allodynia of PSL mice was analyzed via von Frey test. ResultsIn the behavioral test, intravenous administration of SHED-CM greatly improved the PSL-induced hypersensitivity. SHED-CM treatment recruited M2 macrophages in the injured SCN and ipsilateral L4/L5 dorsal root ganglion and suppressed microglial activation in the spinal cord. Speciﬁc depletion of the M2 by mannosylated-Clodrosome markedly reduced the antinociceptive effect of SHED-CM. Intravenous administration of both MCP-1/sSiglec-9 and M2-CM ameliorated the PSL-induced hypersensitivity. We found that M2-CM directly suppressed the expression of nociceptive receptors as well as proinflammatory mediators in Schwann cells. ConclusionTaken together, our data suggest that SHED-CM ameliorates NP through the induction of the analgesic anti-inflammatory M2 macrophages. Thus, SHED-CM may present as a potential novel therapeutic candidate for NP.

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Gastrodia elata Blume Polysaccharides Attenuate Vincristine-Evoked Neuropathic Pain through the Inhibition of Neuroinflammation

Mediators of Inflammation ◽

10.1155/2021/9965081 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Hengtao Xie ◽

Yingying Chen ◽

Wei Wu ◽

Xiaobo Feng ◽

Kairong Du

Keyword(s):

Spinal Cord ◽

Neuropathic Pain ◽

Sciatic Nerve ◽

Inflammatory Cytokines ◽

Thermal Hyperalgesia ◽

Mrna Levels ◽

Gastrodia Elata ◽

Neuroprotective Effects ◽

Gastrodia Elata Blume ◽

Tnf Α

Vincristine (Vin) is a well-known antitumor agent that frequently evokes neuropathic pain and decreases the quality of life of patients. Polysaccharides (GBP) extracted from Gastrodia elata Blume have been demonstrated to possess anti-inflammatory and neuroprotective effects in vivo; however, the effects of GBP on Vin-induced neuropathic pain remain unknown. The present study is aimed at exploring the alleviative potential of GBP against chemotherapy-evoked peripheral neuropathy to better understand and extend its pharmacological application. Vin was administered intraperitoneally to evoke neuropathic pain. GBP was orally administered for 21 days. The mechanical allodynia and thermal hyperalgesia were assessed using the Von Frey test and hot-plate test. Histopathological changes were assessed by hematoxylin and eosin staining. ELISA kits were used to measure the levels of inflammatory cytokines in the sciatic nerve, spinal cord, and dorsal root ganglion (DRG). qRT-PCR was employed to examine the expression of inflammatory cytokines and Sirtuin1 (SIRT1) in the sciatic nerve, spinal cord, and DRG. Our findings revealed that GBP treatment enhanced the paw withdrawal latency and paw withdrawal threshold and restored Vin-induced sciatic nerve damage in rats. GBP also attenuated the Vin-induced increase of proinflammatory cytokine levels, including IL-6, IL-8, TNF-α, IL-1β, and NF-κB. On the molecular level, treatment with GBP downregulated the mRNA levels of IL-6, IL-8, TNF-α, and IL-1β in the sciatic nerve, spinal cord, and DRG. Meanwhile, GBP increased SIRT1 activity and mRNA expression levels. Our data indicated that GBP exerted a potential protective effect against chemotherapy-induced neuropathic pain which might be mediated via the inhibition of neuroinflammation.

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Satellite glial cells express IL-6 and corresponding signal-transducing receptors in the dorsal root ganglia of rat neuropathic pain model

Neuron Glia Biology ◽

10.1017/s1740925x10000074 ◽

2010 ◽

Vol 6 (1) ◽

pp. 73-83 ◽

Cited By ~ 62

Author(s):

Petr Dubový ◽

Ilona Klusáková ◽

Ivana Svíženská ◽

Václav Brázda

Keyword(s):

Neuropathic Pain ◽

Sciatic Nerve ◽

Glial Cells ◽

Dorsal Root Ganglia ◽

Dorsal Root ◽

Thermal Hyperalgesia ◽

Satellite Glial Cells ◽

Neuropathic Pain Model ◽

Stat3 Signalling

There is a growing body of evidence that cytokines contribute to both induction and maintenance of neuropathic pain derived from changes in dorsal root ganglia (DRG), including the activity of the primary sensory neurons and their satellite glial cells (SGC). We used immunofluorescence andin situhybridization methods to provide evidence that chronic constriction injury (CCI) of the sciatic nerve induces synthesis of interleukin-6 (IL-6) in SGC, elevation of IL-6 receptor (IL-6R) and activation of signal transducer and activator of transcription 3 (STAT3) signalling. Unilateral CCI of the rat sciatic nerve induced mechanoallodynia and thermal hyperalgesia in ipsilateral hind paws, but contralateral paws exhibited only temporal changes of sensitivity. We demonstrated that IL-6 mRNA and protein, which were expressed at very low levels in naïve DRG, were bilaterally increased not only in L4-L5 DRG neurons but also in SGC activated by unilateral CCI. Besides IL-6, substantial increase of IL-6R and pSTAT3 expression occurred in SGC following CCI, however, IL-6R associated protein, gp130 levels did not change. The results may suggest that unilateral CCI of the sciatic nerve induces bilateral activation of SGC in L4-L5 DRG to transduce IL-6 signalling during neuroinflammation.

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Alpha lipoic acid attenuated neuropathic pain induced by chronic constriction Injury of sciatic nerve in rats

Clinical Phytoscience ◽

10.1186/s40816-021-00263-7 ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

Prasad Neerati ◽

Harika Prathapagiri

Keyword(s):

Neuropathic Pain ◽

Peripheral Neuropathy ◽

Sciatic Nerve ◽

Lipoic Acid ◽

Normal Saline ◽

Chronic Constriction Injury ◽

Thermal Hyperalgesia ◽

Alpha Lipoic Acid ◽

Chronic Neuropathic Pain ◽

Neuropathic Pain Syndrome

Abstract Background Chronic neuropathic pain syndrome is associated with impaired quality of life and is poorly manageable. Alpha lipoic acid (ALA) is a powerful antioxidant and showed its effectiveness on diabetic neuropathy and other acute peripheral nerve injuries but it was not evaluated in the chronic neuropathic pain, chronic constriction injury (CCI) in rat model by using duloxetine (DLX) as standard. Methodology The main objective of the study was to expedite ALA effect on chronic peripheral neuropathy induced by CCI of sciatic nerve in rats. In this study, male Wister rats were randomly divided into six groups (n = 8) including, normal saline, sham operated, surgery control, DLX 30mg/kg treated, ALA treated 25mg/kg, and ALA+DLX. The CCI of sciatic nerve was conducted on all animals except normal saline group and studied for 21 days (i.e. 14 days treatment period & 7 days treatment free period) by using different behavioral, biochemical and, histopathology studies. Results ALA showed minor but significant decrease of thermal hyperalgesia, cold allodynia, malondialdehyde (MDA), total protein, lipid peroxidation, and nitric oxide levels and significant increase of motor coordination, glutathione level and decreased axonal degeneration significantly. These effects sustained even during treatment free period. ALA enhanced the effect of DLX when given in combination by showing sustained effect. In conclusion, ALA acted as potent antioxidant may be this activity is responsible for the potent neuroprotective effect. Conclusion Hence, ALA attenuated the nueroinflammation mediated by chronic peripheral neuropathy. Further studies are warranted with ALA to develop as a clinically relevant therapeutic agent for the treatment of neuropathic pain.

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SUR1, newly expressed in astrocytes, mediates neuropathic pain in a mouse model of peripheral nerve injury

Molecular Pain ◽

10.1177/17448069211006603 ◽

2021 ◽

Vol 17 ◽

pp. 174480692110066

Author(s):

Orest Tsymbalyuk ◽

Volodymyr Gerzanich ◽

Aaida Mumtaz ◽

Sanketh Andhavarapu ◽

Svetlana Ivanova ◽

...

Keyword(s):

Spinal Cord ◽

Neuropathic Pain ◽

Sciatic Nerve ◽

Peripheral Nerve ◽

Dorsal Horn ◽

Nerve Injury ◽

Peripheral Nerve Injury ◽

Thermal Sensitivity ◽

Gradual Improvement ◽

Pain Behaviors

Background Neuropathic pain following peripheral nerve injury (PNI) is linked to neuroinflammation in the spinal cord marked by astrocyte activation and upregulation of interleukin 6 (IL -6 ), chemokine (C-C motif) ligand 2 (CCL2) and chemokine (C-X-C motif) ligand 1 (CXCL1), with inhibition of each individually being beneficial in pain models. Methods Wild type (WT) mice and mice with global or pGfap-cre- or pGFAP-cre/ERT2-driven Abcc8/SUR1 deletion or global Trpm4 deletion underwent unilateral sciatic nerve cuffing. WT mice received prophylactic (starting on post-operative day [pod]-0) or therapeutic (starting on pod-21) administration of the SUR1 antagonist, glibenclamide (10 µg IP) daily. We measured mechanical and thermal sensitivity using von Frey filaments and an automated Hargreaves method. Spinal cord tissues were evaluated for SUR1-TRPM4, IL-6, CCL2 and CXCL1. Results Sciatic nerve cuffing in WT mice resulted in pain behaviors (mechanical allodynia, thermal hyperalgesia) and newly upregulated SUR1-TRPM4 in dorsal horn astrocytes. Global and pGfap-cre-driven Abcc8 deletion and global Trpm4 deletion prevented development of pain behaviors. In mice with Abcc8 deletion regulated by pGFAP-cre/ERT2, after pain behaviors were established, delayed silencing of Abcc8 by tamoxifen resulted in gradual improvement over the next 14 days. After PNI, leakage of the blood-spinal barrier allowed entry of glibenclamide into the affected dorsal horn. Daily repeated administration of glibenclamide, both prophylactically and after allodynia was established, prevented or reduced allodynia. The salutary effects of glibenclamide on pain behaviors correlated with reduced expression of IL-6, CCL2 and CXCL1 by dorsal horn astrocytes. Conclusion SUR1-TRPM4 may represent a novel non-addicting target for neuropathic pain.

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Short-chain fatty acids contribute to neuropathic pain via regulating microglia activation and polarization

Molecular Pain ◽

10.1177/1744806921996520 ◽

2021 ◽

Vol 17 ◽

pp. 174480692199652

Author(s):

Feng Zhou ◽

Xian Wang ◽

Baoyu Han ◽

Xiaohui Tang ◽

Ru Liu ◽

...

Keyword(s):

Spinal Cord ◽

Neuropathic Pain ◽

Thermal Hyperalgesia ◽

Short Chain Fatty Acids ◽

Antibiotic Administration ◽

Tnf Α ◽

Microglia Polarization ◽

Inflammatory Phenotype ◽

Phenotype Markers ◽

Anti Inflammatory

Microglia activation and subsequent pro-inflammatory responses play a key role in the development of neuropathic pain. The process of microglia polarization towards pro-inflammatory phenotype often occurs during neuroinflammation. Recent studies have demonstrated an active role for the gut microbiota in promoting microglial full maturation and inflammatory capabilities via the production of Short-Chain Fatty Acids (SCFAs). However, it remains unclear whether SCFAs is involved in pro-inflammatory/anti-inflammatory phenotypes microglia polarization in the neuropathic pain. In the present study, chronic constriction injury (CCI) was used to induce neuropathic pain in mice, the mechanical withdrawal threshold, thermal hyperalgesia were accomplished. The levels of microglia markers including ionized calcium-binding adaptor molecule 1 (Iba1), cluster of differentiation 11b (CD11b), pro-inflammatory phenotype markers including CD68, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and anti-inflammatory phenotype markers including CD206, IL-4 in the hippocampus and spinal cord were determined on day 21 after CCI. The results showed that CCI produced mechanical allodynia and thermal hyperalgesia, and also increased the expressions of microglia markers (Iba1, CD11b) and pro-inflammatory phenotype markers (CD68, IL-1β, and TNF-α), but not anti-inflammatory phenotype marker (CD206, IL-4) in the hippocampus and spinal cord, accompanied by increased SCFAs in the gut. Notably, antibiotic administration reversed these abnormalities, and its effects was also bloked by SCFAs administration. In conclusion, data from our study suggest that CCI can lead to mechanical and thermal hyperalgesia, while SCFAs play a key role in the pathogenesis of neuropathic pain by regulating microglial activation and subsequent pro-inflammatory phenotype polarization. Antibiotic administration may be a new treatment for neuropathic pain by reducing the production of SCFAs and further inhibiting the process of microglia polarization.

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Comparative efficacy of pregabalin and baclofen in the rodent chronic constriction injury model of neuropathic pain

International Journal of Basic & Clinical Pharmacology ◽

10.18203/2319-2003.ijbcp20185171 ◽

2018 ◽

Vol 8 (1) ◽

pp. 133

Author(s):

Saurabh Kohli ◽

Taruna Sharma ◽

Juhi Kalra ◽

Dilip C. Dhasmana

Keyword(s):

Neuropathic Pain ◽

Sciatic Nerve ◽

Chronic Constriction Injury ◽

Thermal Hyperalgesia ◽

Mechanical Hyperalgesia ◽

Comparative Efficacy ◽

First Line ◽

Injury Model ◽

Different Types ◽

Chronic Constriction Injury Model

Background: Neuropathic pain is associated with prolonged disability and is usually not responsive to conventional analgesics like NSAIDs and opioids. Even the recommended first-line drugs are effective in less than 50% patients. Thus, drugs with different mechanisms of action are needed. Baclofen, a GABA-B agonist has shown benefit in different types of neuropathic pains and is compared against pregabalin.Methods: The sciatic nerve was ligated in 2 groups of 6 rats each as per the chronic constriction injury model of neuropathic pain on day 0. After 14 days the effect of single doses of pregabalin (30mg/kg) and baclofen (5mg/kg) intraperitoneally were assessed over a 2 hours period. Thermal and mechanical hyperalgesia were assessed as measures of neuropathic pain by the hotplate and pin-prick method respectively.Results: Significant thermal and mechanical hyperalgesia was produced 14 days after sciatic nerve ligation in both the groups (p <0.05). Both pregabalin (p <0.001) and baclofen (p <0.01) were effective in decreasing thermal hyperalgesia throughout the two hours study period, but pregabalin was more effective as compared to baclofen (p <0.05) at 30, 60 and 120minutes. Both the drugs produced a significant decrease in mechanical hyperalgesia (p <0.01) throughout the study period. Again, pregabalin was the more effective drug (p <0.05) at all time points.Conclusions: Significant thermal and mechanical hyperalgesia was seen 14 days after sciatic nerve ligation. Both pregabalin and baclofen were effective in reversing the hyperalgesia, but pregabalin was the more effective of the two drugs at all time points.

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CB2/miR-124 signaling down-regulate the expression of purinergic P2X4 and P2X7 receptor in dorsal spinal cord of CCI rats

10.21203/rs.2.22085/v1 ◽

2020 ◽

Author(s):

Rui Xu ◽

Fan Yang ◽

Lijuan Li ◽

Xiaohong Liu ◽

Xiaolu Lei ◽

...

Keyword(s):

Spinal Cord ◽

Neuropathic Pain ◽

Sciatic Nerve ◽

Nerve Injury ◽

Intrathecal Injection ◽

Receptor Activation ◽

Cb2 Receptor ◽

Dorsal Spinal Cord ◽

P38mapk Pathway ◽

Dorsal Spinal

Abstract Background: The importance of P2X purinoceptors, CB2 receptor and microRNA-124(miR-124) in spinal cord microglia to the development of neuropathic pain was demonstrated in numerous previous studies. The upregulation of P2X4 and P2X7 receptors in spinal dorsal horn microglia is involved in the development of pain behavior caused by peripheral nerve injury. However, it is not clear whether the expression of P2X4 and P2X7 receptors at dorsal spinal cord will be influenced by CB2 receptor or miR-124 in rats after chronic sciatic nerve injury.Methods: Chronic constriction injury (CCI) of the sciatic nerve was performed in rats to induce neuropathic pain. Tests of the mechanical withdrawal threshold (MWT) were carried out to assess the response of the paw to mechanical stimulus. The expression of miR-124, P2X4, P2X7 and CB2 receptor were detected with RT-PCR. The protein expression of P2X4, P2X7 and CB2 receptor, RhoA, ROCK1, ROCK2, p-p38MAPK and p-NF-kappaBp65 was detected with Western blotting analysis. Results: Intrathecal administration of CB2 receptor agonist AM1241 significantly attenuated CCI-induced mechanical allodynia and significantly inhibited the increased expression of P2X4 and P2X7 receptors at the mRNA and protein levels, which imply that P2X4 and P2X7 receptors expression are down-regulated by AM1241 in CCI rats. Western blot analysis showed that AM1241 suppressed the elevated expression of RhoA, ROCK1, ROCK2, p-p38MAPK and NF-κBp65 in the dorsal spinal cord induced by CCI. After administration with Y-27632 (ROCK inhibitor), SB203580 (P38MAPK inhibitor) or PDTC (NF-κB inhibitor), the levels of P2X4 and P2X7 receptors expression in the dorsal spinal cord were lower than those in CCI rats, which imply that the ROCK/P38MAPK pathway and NF-κB activation may contribute to the increased expression of P2X4 and P2X7 receptor. On the other hand, in CCI rats, AM1241 treatment evoked the increased expression of CB2 receptor and miRNA-124, which can be inhibited by intrathecal injection of CB2 receptor antagonist AM630, which indicate that the increased expression of miRNA-124 may be medicated by CB2 receptor activation. In addition, the increased expression of P2X4 and P2X7 receptors in the dorsal spinal cord of CCI rats were inhibited by miRNA-124 agomir. Furthermore, intrathecal injection of miRNA-124 agomir could efficiently inhibit the ROCK/P38MAPK pathway and NF-κB activation in CCI rats. Moreover, AM1241 treatment significantly inhibited the expression of P2X4 and P2X7 receptors, and this suppression is enhanced by pretreatment with miRNA-124 agomir. On the contrast, the inhibitory effect of AM1241 on the expression of P2X4 and P2X7 receptor can be reversed by pretreatment with miRNA-124 antagomir.Conclusions: In CCI rats, intrathecal injection of AM1241 could efficiently induce the increased expression of miRNA-124, while inhibiting the ROCK/P38MAPK pathway and NF-κB activation in dorsal spinal cord. CB2 receptor/miRNA-124 signaling induced the decreased P2X4 and P2X7 receptors expression via inhibit the ROCK/P38MAPK pathway and NF-κB activation.

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Salvia officinalis, Rosmarinic and Caffeic Acids Attenuate Neuropathic Pain and Improve Function Recovery after Sciatic Nerve Chronic Constriction in Mice

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2019/1702378 ◽

2019 ◽

Vol 2019 ◽

pp. 1-17 ◽

Cited By ~ 1

Author(s):

Zineb El Gabbas ◽

Kenza Bezza ◽

Jawad Laadraoui ◽

Mehdi Ait Laaradia ◽

Aaziz Kebbou ◽

...

Keyword(s):

Neuropathic Pain ◽

Sciatic Nerve ◽

Functional Recovery ◽

Thermal Sensation ◽

Biological Activities ◽

Hematological Parameters ◽

Thermal Hyperalgesia ◽

Salvia Officinalis ◽

Histopathological Analysis ◽

Phenolic Constituents

The leaves of Salvia officinalis L. have a traditional reputation for the management of pain in Morocco. This study was conducted to investigate the curative effects of Salvia officinalis (SO) and its major constituents Rosmarinic (ROS) and Caffeic acids (CAF) on peripheral neuropathic pain in mice. Chronic constriction injury (CCI) was induced in mice, and neuropathic pain behaviors tests were evaluated by mechanical, chemical, thermal sensation tests and functional recovery of the sciatic nerve at different time intervals, i.e., (day 0, 1, 7, 14, and 21). Ethanolic extract of SO (100 and 200 mg/kg, p.o.), ROS (10 and 20 mg/kg, i.p.), CAF (30 and 40 mg/kg, i.p.), and CLOM (5 mg/kg, i.p., a positive control) was given for 21 days after surgery. Hematological and biochemical parameters were also measured as well as histopathological analysis. CCI produced significant development in mechanical and thermal hyperalgesia, cold allodynia, and rise in the sciatic functional index in mice. Chronic treatments with SO extract, ROS, CAF, and CLOM for 3 weeks significantly increased mechanical sensibility, cold, and thermal withdrawal latency and enhanced functional recovery of the injured nerve. The same treatments remarkably ameliorated hematological parameters and did not alter biochemical levels. The histopathological findings had revealed the protective effect of SO, ROS, and CAF against the CCI-induced damage. Our data support the use of SO in folk medicine to alleviate pain. Their main phenolic constituents could be promising antineuropathic compounds, which may be attributed to their biological activities including anti-inflammatory, antioxidant, and neuroprotective effects. SO leaves may be a good candidate to treat neuropathic pain.

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