Upregulation of Cystathionine β-Synthetase Expression Contributes to Visceral Hyperalgesia Induced by Heterotypic Intermittent Stress in Rats

Yongmeng Wang,Ying Xiao,Xinghong Jiang,Ruobing Qu,Guang-Yin Xu,Shufen Hu,Shu-Min Duan

doi:10.1371/journal.pone.0053165

Yongmeng Wang, Ying Xiao + Show 5 more

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https://doi.org/10.1371/journal.pone.0053165

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Journal: PLoS ONE	Publication Date: Dec 28, 2012
Citations: 31	License type: CC BY 4.0

Affiliation: Soochow University

Abstract

BackgroundHydrogen sulfide (H2S) functions as a neuromodulator, but whether it modulates visceral pain is not well known. This study was designed to determine the role for the endogenous H2S producing enzyme cystathionine β-synthetase (CBS) and cystathionine γ-lyase (CSE) in a validated rat model of visceral hyperalgesia (VH).MethodsVH was induced by nine-day heterotypic intermittent stress (HIS). Abdominal withdrawal reflex (AWR) scores were determined by measuring the visceromoter responses to colorectal distension (CRD). Dorsal root ganglia (DRG) neurons innervating the colon were labeled by injection of DiI (1,1'-dioleyl-3,3,3',3-tetramethylindocarbocyanine methanesulfonate) into the colon wall. Patch clamp recording techniques were employed to examine excitability and sodium channel currents of colon specific DRG neurons. Tissues from colon related thoracolumbar DRGs were analyzed for CBS, CSE and sodium channel expression.ResultsHIS significantly increased the visceromotor responses to CRD in association with an upregulated expression of CBS not CSE proteins in colon related DRGs. Administration of O-(Carboxymethyl)hydroxylamine hemihydrochloride (AOAA), an inhibitor of CBS, attenuated the AWR scores in HIS-treated rats, in a dose dependent fashion. In contrast, AOAA did not produce any effect on AWR scores in healthy control rats. AOAA reversed the potentiation of sodium channel current densities of colon specific DRG neurons of HIS rats. To further confirm the role for CBS-H2S signaling, NaHS was used to mimic the production of H2S by CBS. Application of NaHS significantly enhanced neuronal excitability and potentiated sodium channel current densities of colon DRG neurons from healthy control rats. Furthermore, AOAA reversed the upregulation of NaV1.7 and NaV1.8 in colon related DRGs of HIS rats.ConclusionOur results suggest that upregulation of CBS expression might play an important role in developing VH via sensitization of sodium channels in peripheral nociceptors, thus identifying a specific neurobiological target for the treatment of VH in functional bowel syndromes.

Highlights

Irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, is characterized by altered bowel evacuation, bloating and visceral pain in the absence of anatomical or biochemical abnormalities [1,2]
heterotypic intermittent stress (HIS)-induced Visceral Hypersensitivity was Associated with an Upregulation of cystathionine bsynthetase (CBS) Expression
HIS significantly increased CBS expression in T13-L2 Dorsal root ganglia (DRG) at 6, 24 and 48 h and the expression was returned to normal level 1 week after termination of the last stressor (Fig. 1C, HIS 6 h/ CON = 2.95; HIS 24 h/CON = 2.88; HIS 48 h/CON = 2.46; HIS 1 w/CON = 1.09; n = 3 rats for control and 1 week; n = 4 rats for 6, 24 and 48 h; *p,0.05 vs. CON, one-way ANOVA followed by Tukey post hoc test)

Summary

Introduction

Irritable bowel syndrome (IBS), a common functional gastrointestinal disorder, is characterized by altered bowel evacuation, bloating and visceral pain in the absence of anatomical or biochemical abnormalities [1,2]. Recent studies have showed that stress is related with symptom onset, exacerbation and perpetuation in patients with functional gastrointestinal disorders [3]. Clinical studies show that chronic stress plays an important role in the pathophysiology of IBS [7]. Altered visceral sensitivity with increased responses to colorectal distension (CRD) consistently presents and is recognized as a hallmark of IBS in clinic [8,9,10]. Stress-induced visceral hypersensitivity is proposed to be a significant component in the pathophysiology of IBS. The precise mechanism of stress-induced visceral hypersensitivity remains unknown. This study was designed to determine the role for the endogenous H2S producing enzyme cystathionine bsynthetase (CBS) and cystathionine c-lyase (CSE) in a validated rat model of visceral hyperalgesia (VH)

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Conclusion