Neonatal Colonic Inflammation Increases Spinal Transmission and Cystathionine β-Synthetase Expression in Spinal Dorsal Horn of Rats with Visceral Hypersensitivity

Background Irritable bowel syndrome is one of the most common gastrointestinal disorders. It is featured by abdominal pain in conjunction with altered bowel habits. However, the pathophysiology of the syndrome remains largely unknown. Tumor necrosis factor receptor-associated factor 6 (TRAF6) has been reported to be involved in neuropathic pain. The aim of this study was to investigate roles and mechanisms of TRAF6 in the chronic visceral hypersensitivity. Methods Visceral hypersensitivity was induced by neonatal colonic inflammation and was identified by colorectal distention. The protein level, RNA level, and cellular distribution of TRAF6 and its related molecules were detected with Western blot, quantitative polymerase chain reaction, and immunofluorescence. In vitro spinal cord slice recording technique was performed to determine the synaptic transmission activities. Results Neonatal colonic inflammation rats displayed visceral hypersensitivity at the age of six weeks. The expression of TRAF6 was obviously upregulated in spinal cord dorsal horn of neonatal colonic inflammation rats at the age of six weeks. Immunofluorescence study showed that TRAF6 was dominantly expressed in spinal astrocytes. Intrathecal injection of TRAF6 small interfering RNA (siRNA) significantly reduced the amplitude of spontaneous excitatory postsynaptic currents at the spinal dorsal horn level. Furthermore, knockdown of TRAF6 led to a significant downregulation of cystathionine β synthetase expression in the spinal dorsal horn of neonatal colonic inflammation rats. Importantly, intrathecal injection of TRAF6 siRNA remarkably alleviated visceral hypersensitivity of neonatal colonic inflammation rats. Conclusions Our results suggested that the upregulation of TRAF6 contributed to visceral pain hypersensitivity, which is likely mediated by regulating cystathionine β synthetase expression in the spinal dorsal horn. Our findings suggest that TRAF6 might act as a potential target for the treatment of chronic visceral pain in irritable bowel syndrome patients.

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Sini-San Regulates the NO-cGMP-PKG Pathway in the Spinal Dorsal Horn in a Modified Rat Model of Functional Dyspepsia

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2020/3575231 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Zhenyu Wu ◽

Xiaofang Lu ◽

Shengsheng Zhang ◽

Chunyang Zhu

Keyword(s):

Gene Expression ◽

Dorsal Horn ◽

Functional Dyspepsia ◽

Rat Model ◽

Spinal Dorsal Horn ◽

Visceral Hypersensitivity ◽

Enzyme Linked Immunosorbent Assay ◽

Gastric Distention ◽

Real Time Quantitative Pcr ◽

Spinal Dorsal

The present study investigated the effect of Chinese medicine Sini-San (SNS) on visceral hypersensitivity in a rat model of functional dyspepsia (FD), and it explored related underlying mechanisms. The rat model of FD was developed by combining neonatal iodoacetamide (IA) treatment and adult tail-clamping. After SNS treatment, the behavior and electromyographic testing were performed to evaluate the visceromotor responses of rats to gastric distention. Immunofluorescence was used to detect the distribution of iNOS-positive cells in the spinal dorsal horn, while the real-time quantitative PCR and western blot were used for detection of the gene expression of c-fos, iNOS, and GABAb and protein levels of iNOS and GABAb in the spinal dorsal horn, respectively. The protein concentration of cGMP and PKG proteins in the spinal dorsal horn were quantified by enzyme-linked immunosorbent assay. In this study, SNS treatment significantly reduced the behavioral score and electromyographic response to graded intragastric distension pressure. The middle-dose of SNS treatment significantly reduced the distribution of iNOS-positive cells in the spinal dorsal horn of FD model rats. The gene expression of c-fos, iNOS, and GABAb and the protein contents of iNOS, GABAb, cGMP, and PKG in the spinal dorsal horn of FD model rats were restored to a normal level by middle-dose of SNS treatment. Our results suggest that Sini-San may alleviate the visceral hypersensitivity in FD model rats via regulation of the NO/cGMP/PKG pathway in the spinal dorsal horn.

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TRPA1 in the spinal dorsal horn is involved in post-inflammatory visceral hypersensitivity: in vivo study using TNBS-treated rat model

Journal of Pain Research ◽

10.2147/jpr.s118581 ◽

2016 ◽

Vol Volume 9 ◽

pp. 1153-1160 ◽

Cited By ~ 7

Author(s):

Qian Li ◽

Chenghao Guo ◽

Mohammed Ali Chowdhury ◽

Taoli Dai ◽

Wei Han

Keyword(s):

Dorsal Horn ◽

Rat Model ◽

Spinal Dorsal Horn ◽

Visceral Hypersensitivity ◽

In Vivo Study ◽

Spinal Dorsal

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Single Intraperitoneal Injection of Low-Dose Ketamine Pretreatment Alleviates Mechanical Hyperalgesia and Downregulates the Expression of Inflammatory Cytokines in Spinal Dorsal Horn of Rats

Journal of Anesthesia and Perioperative Medicine ◽

10.24015/japm.2015.0032 ◽

2015 ◽

Vol 2 (5) ◽

pp. 236-243

Author(s):

Li Xu ◽

Yu Shen ◽

Lin Liu ◽

Yin Cui ◽

Xiao-Ping Gu ◽

...

Keyword(s):

Dorsal Horn ◽

Inflammatory Cytokines ◽

Intraperitoneal Injection ◽

Spinal Dorsal Horn ◽

Low Dose ◽

Mechanical Hyperalgesia ◽

Spinal Dorsal ◽

Single Intraperitoneal Injection

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Faculty Opinions recommendation of Spread of excitation across modality borders in spinal dorsal horn of neuropathic rats.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1105023.561186 ◽

2008 ◽

Author(s):

Nanna Finnerup

Keyword(s):

Dorsal Horn ◽

Spinal Dorsal Horn ◽

Spinal Dorsal ◽

Spread Of Excitation

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Faculty Opinions recommendation of Innocuous, not noxious, input activates PKCgamma interneurons of the spinal dorsal horn via myelinated afferent fibers.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1120062.576194 ◽

2008 ◽

Author(s):

Nanna Finnerup

Keyword(s):

Dorsal Horn ◽

Spinal Dorsal Horn ◽

Spinal Dorsal ◽

Afferent Fibers

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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

Journal of Neuroinflammation ◽

10.1186/s12974-021-02168-1 ◽

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.

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