Effects of Tetramethylpyrazine on Neuronal Apoptosis in the Superficial Dorsal Horn in a Rat Model of Neuropathic Pain

2012 ◽  
Vol 40 (06) ◽  
pp. 1229-1239 ◽  
Author(s):  
Yu-Fang Leng ◽  
Xiang-Mei Gao ◽  
Shu-Xiu Wang ◽  
Yan-Hong Xing
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Neuronal Apoptosis ◽  
Caspase 3 ◽  
Sham Group ◽  
Male Rats ◽  
Spinal Dorsal ◽  
Post Operation ◽  
The Right

The Bennett and Xie (1988) model of chronic constriction injury (CCI) investigated the effects of tetramethylpyrazine (TMP) on neuropathic pain-associated behaviors and neuronal apoptosis in the spinal dorsal horn. Fifty-four male rats were randomly divided into sham (group S), CCI (group C) and TMP groups (group T). Each group was divided into subgroups (n = 6 in each group) according the time of sacrifice: 3 d, 7 d and 14 d. Rat sciatic nerves were unligated (group S), or the right sciatic nerve was loosely ligated (groups C and T) to produce CCI. Mechanical withdrawal thresholds (MWTs) and thermal withdrawal latencies (TWLs) were measured, and the rats were sacrificed at different time points post-operation. The L4-L6 sections of the spinal cord were removed. Apoptotic changes were evaluated using the TUNEL method. Immunohistochemistry assessed Bcl-2 and caspase-3 expression. TMP treatment increased MWT and TWL values and Bcl-2 expression, but it reduced neuronal apoptosis and caspase-3 expression in laminae I–II of the spinal dorsal horn. These results suggested that the inhibition of neuronal apoptosis via the modulation of Bcl-2 and caspase-3 proteins in the rat spinal dorsal horn contributed to TMP-induced analgesia.

scholarly journals Spinal α2-Adrenoceptor-mediated Analgesia in Neuropathic Pain Reflects Brain-derived Nerve Growth Factor and Changes in Spinal Cholinergic Neuronal Function

2010 ◽  
Vol 113 (2) ◽  
pp. 406-412 ◽  
Author(s):  
Ken-ichiro Hayashida ◽  
James C. Eisenach
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Choline Acetyltransferase ◽  
Spinal Dorsal Horn ◽  
Acetylcholine Release ◽  
Cholinergic Neurons ◽  
Male Rats ◽  
Spinal Dorsal ◽  
Alpha2 Adrenoceptor

Introduction Spinal alpha2-adrenoceptor stimulation produces analgesia in neuropathic pain states, and this effect in animals is blocked by the inhibitors of brain-derived neurotrophic factor (BDNF) function. In rats, alpha2-adrenoceptor stimulation normally inhibits acetylcholine release, but it excites release after nerve injury. The authors examined the roles of BDNF and excitatory Gs-protein in this change. Methods Male rats underwent L5-L6 spinal nerve ligation (SNL), and their lumbar spinal dorsal horns with or without spinal BDNF infusion were used for either synaptosome preparation for acetylcholine release or immunostaining for choline acetyltransferase. Results SNL did not alter spontaneous release from synaptosomes or choline acetyltransferase immunoreactivity in the spinal dorsal horn, but it reduced KCl-evoked acetylcholine release. Dexmedetomidine inhibited KCl-evoked acetylcholine release in synaptosomes from normal rats, but it excited KCl-evoked release in synaptosomes from SNL rats, and both effects were blocked by the alpha2-adrenoceptor antagonist idazoxan. Spinal infusion of an antibody to BDNF reduced choline acetyltransferase immunoreactivity in the spinal dorsal horn in both normal and SNL rats and abolished facilitation of KCl-evoked acetylcholine release by dexmedetomidine in SNL rats. Dexmedetomidine facilitation of acetylcholine release was also blocked by the inhibitors of Gs function. Discussion The increased reliance of spinal alpha2 adrenoceptors on cholinergic stimulation to cause analgesia after nerve injury reflects in part a shift from direct inhibition to direct excitation of spinal cholinergic neurons. The authors' results suggest that this shift relies on an interaction with Gs-proteins and BDNF.

scholarly journals Calcitonin gene-related peptide regulates spinal microglial activation through the histone H3 lysine 27 trimethylation via enhancer of zeste homolog-2 in rats with neuropathic pain

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Qi An ◽  
Chenyan Sun ◽  
Ruidi Li ◽  
Shuhui Chen ◽  
Xinpei Gu ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Nerve Injury ◽  
Spinal Dorsal Horn ◽  
Microglial Activation ◽  
Microglial Cells ◽  
Gene Promoters ◽  
Spinal Dorsal ◽  
Related Peptide ◽  
Calcitonin Gene

Abstract Background Calcitonin gene-related peptide (CGRP) as a mediator of microglial activation at the transcriptional level may facilitate nociceptive signaling. Trimethylation of H3 lysine 27 (H3K27me3) by enhancer of zeste homolog 2 (EZH2) is an epigenetic mark that regulates inflammatory-related gene expression after peripheral nerve injury. In this study, we explored the relationship between CGRP and H3K27me3 in microglial activation after nerve injury, and elucidated the underlying mechanisms in the pathogenesis of chronic neuropathic pain. Methods Microglial cells (BV2) were treated with CGRP and differentially enrichments of H3K27me3 on gene promoters were examined using ChIP-seq. A chronic constriction injury (CCI) rat model was used to evaluate the role of CGRP on microglial activation and EZH2/H3K27me3 signaling in CCI-induced neuropathic pain. Results Overexpressions of EZH2 and H3K27me3 were confirmed in spinal microglia of CCI rats by immunofluorescence. CGRP treatment induced the increased of H3K27me3 expression in the spinal dorsal horn and cultured microglial cells (BV2) through EZH2. ChIP-seq data indicated that CGRP significantly altered H3K27me3 enrichments on gene promoters in microglia following CGRP treatment, including 173 gaining H3K27me3 and 75 losing this mark, which mostly enriched in regulation of cell growth, phagosome, and inflammation. qRT-PCR verified expressions of representative candidate genes (TRAF3IP2, BCL2L11, ITGAM, DAB2, NLRP12, WNT3, ADAM10) and real-time cell analysis (RTCA) verified microglial proliferation. Additionally, CGRP treatment and CCI increased expressions of ITGAM, ADAM10, MCP-1, and CX3CR1, key mediators of microglial activation in spinal dorsal horn and cultured microglial cells. Such increased effects induced by CCI were suppressed by CGRP antagonist and EZH2 inhibitor, which were concurrently associated with the attenuated mechanical and thermal hyperalgesia in CCI rats. Conclusion Our findings highly indicate that CGRP is implicated in the genesis of neuropathic pain through regulating microglial activation via EZH2-mediated H3K27me3 in the spinal dorsal horn.

Driving effect of BDNF in the spinal dorsal horn on neuropathic pain

2021 ◽  
pp. 135965
Author(s):  
Zhou Wu ◽  
Xie Zhiping ◽  
Li Chengcai ◽  
Zelong Xing ◽  
Xie Shenke ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Spinal Dorsal

353 INHIBITION OF COX-2 EXPRESSION IN RAT SPINAL DORSAL HORN BY ELECTROACUPUNCTURE IN NEUROPATHIC PAIN

2007 ◽  
Vol 11 (S1) ◽  
pp. S156-S157
Author(s):  
W.K. Lau ◽  
W.K. Chan ◽  
W.T. Chan ◽  
J.L. Zhang ◽  
H.Q. Zhang
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Spinal Dorsal ◽  
Cox 2

scholarly journals Hypersensitivity of Spinothalamic Tract Neurons Associated With Diabetic Neuropathic Pain in Rats

2002 ◽  
Vol 87 (6) ◽  
pp. 2726-2733 ◽  
Author(s):  
Shao-Rui Chen ◽  
Hui-Lin Pan
Keyword(s):  
Neuropathic Pain ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Thermal Hyperalgesia ◽  
Diabetic Rats ◽  
Projection Neurons ◽  
Diabetic Neuropathic Pain ◽  
Spinothalamic Tract ◽  
Functional Changes ◽  
Spinal Dorsal

Diabetic neuropathic pain is often considered to be caused by peripheral neuropathy. The involvement of the CNS in this pathological condition has not been well documented. Development of hypersensitivity of spinal dorsal horn neurons is involved in neuropathic pain induced by traumatic nerve injury. In the present study, we determined the functional changes of identified spinothalamic tract (STT) neurons and their correlation to diabetic neuropathic pain. Diabetes was induced in rats by intraperitoneal injection of streptozotocin. Hyperalgesia and allodynia were assessed by the withdrawal responses to pressure, radiant heat, and von Frey filaments applied to the hindpaw. Single-unit activity of STT neurons was recorded from the lumbar spinal cord in anesthetized rats. The responses of STT neurons to mechanical and thermal stimuli and the sensitivity to intravenous morphine were determined in diabetic and normal rats. In 12 diabetic rats, mechanical allodynia and hyperalgesia, but not thermal hyperalgesia, developed within 2 wk after streptozotocin injection and lasted for ≥7 wk. Compared to the 32 STT neurons recorded in normal animals, the 37 STT neurons in diabetic rats displayed a higher spontaneous discharge activity and enlarged receptive fields. Also, the STT neurons in diabetic rats exhibited lower thresholds and augmented responses to mechanical stimulation. Intravenous injection of 2.5 mg/kg of morphine suppressed significantly the responses of STT neurons to noxious stimuli in 12 nondiabetic rats. However, such an inhibitory effect of morphine on the evoked response of STT neurons was diminished in 14 diabetic animals. This electrophysiological study provides new information that development of hypersensitivity of spinal dorsal horn projection neurons may be closely related to neuropathic pain symptoms caused by diabetes. Furthermore, the attenuated inhibitory effects of morphine on evoked responses of STT neurons in diabetes likely accounts for its reduced analgesic efficacy in this clinical form of neuropathic pain.

Sirtuin 1 alleviates diabetic neuropathic pain by regulating synaptic plasticity of spinal dorsal horn neurons

Pain ◽  
2019 ◽  
Vol 160 (5) ◽  
pp. 1082-1092 ◽  
Author(s):  
Zongqin Zhang ◽  
Xiaobao Ding ◽  
Zhiwei Zhou ◽  
Zhuang Qiu ◽  
Naihao Shi ◽  
...  
Keyword(s):  
Neuropathic Pain ◽  
Synaptic Plasticity ◽  
Dorsal Horn ◽  
Spinal Dorsal Horn ◽  
Sirtuin 1 ◽  
Diabetic Neuropathic Pain ◽  
Dorsal Horn Neurons ◽  
Spinal Dorsal ◽  
Spinal Dorsal Horn Neurons
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