Inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn's disease, are multifactorial, chronic, disabling, and progressive diseases characterised by cyclical nature, alternating between active and quiescent states. While the aetiology of IBD is not fully understood, this complex of diseases involve a combination of factors including the genetic predisposition and changes in microbiome as well as environmental risk factors such as high-fat and low-fibre diets, reduced physical activity, air pollution and exposure to various toxins and drugs such as antibiotics. The prevalence of both IBD and obesity is increasing in parallel, undoubtedly proving the existing interactions between these risk factors common to both disorders to unravel poorly recognized cell signaling and molecular alterations leading to human IBD. Therefore, there is still a significant and unmet need for supportive and adjunctive therapy for IBD patients directed against the negative consequences of visceral obesity and bacterial dysbiosis. Among the alternative therapies, a moderate-intensity exercise can benefit the health and well-being of IBD patients and improve both the healing of human IBD and experimental animal colitis. Intestinal alkaline phosphatase (IAP) plays an essential role in the maintenance of intestinal homeostasis intestinal and the mechanism of mucosal defence. The administration of exogenous IAP could be recommended as a therapeutic strategy for the cure of diseases resulting from the intestinal barrier dysfunction such as IBD. Curcumin, a natural anti-inflammatory agent, which is capable of stimulating the synthesis of endogenous IAP, reprerk cents another alternative approach in the treatment of IBD. This review was designed to discuss potential "nonpharmacological" alternative and supplementary therapeutic approaches taking into account epidemiological and pathophysiological links between obesity and IBD, including changes in the functional parameters of the intestinal mucosa and alterations in the intestinal microbiome.

Exposure to acidic gastric content due to malfunction of lower esophageal sphincter leads to acute reflux esophagitis (RE) leading to disruption of esophageal epithelial cells. Carbon monoxide (CO) produced by heme oxygenase (HMOX) activity or released from its donor, tricarbonyldichlororuthenium (II) dimer (CORM-2) was reported to protect gastric mucosa against acid-dependent non-steroidal anti-inflammatory drug-induced damage. Thus, we aimed to investigate if CO affects RE-induced esophageal epithelium lesions development. RE induced in Wistar rats by the ligation of a junction between pylorus and forestomach were pretreated i.g. with vehicle CORM-2; RuCl3; zinc protoporphyrin IX, or hemin. CORM-2 was combined with NG-nitro-L-arginine (L-NNA), indomethacin, capsazepine, or capsaicin-induced sensory nerve ablation. Esophageal lesion score (ELS), esophageal blood flow (EBF), and mucus production were determined by planimetry, laser flowmetry, histology. Esophageal Nrf-2, HMOXs, COXs, NOSs, TNF-α and its receptor, IL-1 family and IL-1 receptor antagonist (RA), NF-κB, HIF-1α, annexin-A1, suppressor of cytokine signaling (SOCS3), TRPV1, c-Jun, c-Fos mRNA/protein expressions, PGE2, 8-hydroxy-deoxyguanozine (8-OHdG) and serum COHb, TGF-β1, TGF-β2, IL-1β, and IL-6 content were assessed by PCR, immunoblotting, immunohistochemistry, gas chromatography, ELISA or Luminex platform. Hemin or CORM-2 alone or combined with L-NNA or indomethacin decreased ELS. Capsazepine or capsaicin-induced denervation reversed CORM-2 effects. COHb blood content, esophageal HMOX-1, Nrf-2, TRPV1 protein, annexin-A1, HIF-1α, IL-1 family, NF-κB, c-Jun, c-Fos, SOCS3 mRNA expressions, and 8-OHdG levels were elevated while PGE2 concentration was decreased after RE. CO donor-maintained elevated mucosal TRPV1 protein, HIF-1 α, annexin-A1, IL-1RA, SOCS3 mRNA expression, or TGF-β serum content, decreasing 8-OHdG level, and particular inflammatory markers expression/concentration. CORM-2 and Nrf-2/HMOX-1/CO pathway prevent esophageal mucosa against RE-induced lesions, DNA oxidation, and inflammatory response involving HIF-1α, annexin-A1, SOCS3, IL-1RA, TGF-β-modulated pathways. Esophagoprotective and hyperemic CO effects are in part mediated by afferent sensory neurons and TRPV1 receptors activity with questionable COX/PGE2 or NO/NOS systems involvement.

Introduction: Bone morphogenetic protein 4 (BMP4) signaling is activated in Barrett's esophagus, the condition in which metaplastic columnar cells with malignant predisposition replace esophageal squamous cells damaged by GERD.In earlier studies, we reported that: 1) BMP4 activates expression of SOX9 (a transcription factor that can upregulate expression of columnar cytokeratins in esophageal squamous epithelium); and 2) BMP4 signaling can occur through BMP type I receptor-mediated activation of both the canonical pathway (through SMAD proteins) and the non-canonical pathway (through p38MAPK).Based on these findings, we hypothesized that an inhibitory SMAD would reduce canonical BMP4 signaling and SOX9 expression in Barrett's metaplasia.To explore this hypothesis, we sought to determine whether SMAD6, an inhibitory SMAD, decreases SOX9 expression in human Barrett's columnar cells and in esophageal squamous cells derived from patients with Barrett's esophagus.Methods: Telomerase-immortalized Barrett's (BAR-T and BAR-10T) and squamous (NES-B3T and NES-B10T) epithelial cell lines were transfected with inhibitory SMAD6 in the presence or absence of human recombinant BMP4.We performed: a) Western blot analysis for total and phosphorylated-SMAD1/5/8 (pSMAD1/5/8), total and phosphorylated-p38MAPK, NF-YB (a transcription factor downstream of the p38MAPK pathway), and SOX9; b) real-time PCR analysis for SOX9, ID1 (a BMP4 target gene activated by both canonical and non-canonical signaling), and MSX2 (a gene activated by SMADs); c) luciferase assay using an ID1 reporter construct; and d) chromatin immunoprecipitation (ChIP assay) for pSMAD1/5/8 or NF-YB binding to the SOX9 promoter.Results: In both squamous and Barrett's cell lines, SMAD6 transfection resulted in significant reductions in SOX9 and MSX2 expression and in transcriptional activity of ID1, all associated with decreased levels of pSMAD1/5/8.In contrast, SMAD6 transfection did not influence the p38MAPK pathway in any cell line.ChIP assay demonstrated that SMAD6 transfection decreased pSMAD1/5/8 binding to an identified SMAD binding element (SBE) on the SOX9 promoter.NF-YB binding to the CCATT box on the SOX9 promoter was not affected by transfection with SMAD6, further evidence that SMAD6 does not influence non-canonical BMP signaling.Conclusion: In both esophageal squamous and Barrett's columnar epithelial cells, SMAD6 reduces BMP4induced expression of SOX9 through effects on SMAD proteins, not on the p38MAPK pathway.These findings suggest that esophageal BMP4 signaling through the canonical SMAD pathway can induce squamous cells to express columnar cell transcription factors that might contribute to the pathogenesis of Barrett's esophagus.We speculate that agents targeting the SMAD pathway might prevent the development of Barrett's esophagus in patients with GERD.

Inflammatory bowel diseases (IBDs) are a group of disorders which include ulcerative colitis and Crohn's disease. Obesity is becoming increasingly more common among patients with inflammatory bowel disease and plays a role in the development and course of the disease. This is especially true in the case of Crohn's disease. The recent results indicate a special role of visceral adipose tissue and particularly mesenteric adipose tissue, also known as "creeping fat", in pathomechanism, leading to intestinal inflammation. The involvement of altered adipocyte function and the deregulated production of adipokines, such as leptin and adiponectin, has been suggested in pathogenesis of IBD. In this review, we discuss the epidemiology and pathophysiology of obesity in IBD, the influence of a Western diet on the course of Crohn's disease and colitis in IBD patients and animal's models, and the potential role of adipokines in these disorders. Since altered body composition, decrease of skeletal muscle mass, and development of pathologically changed mesenteric white adipose tissue are well-known features of IBD and especially of Crohn's disease, we discuss the possible crosstalk between adipokines and myokines released from skeletal muscle during exercise with moderate or forced intensity. The emerging role of microbiota and the antioxidative and anti-inflammatory enzymes such as intestinal alkaline phosphatase is also discussed, in order to open new avenues for the therapy against intestinal perturbations associated with IBD.

BACKGROUND:Curcumin, a pleiotropic substance used for centuries in traditional medicine, exhibits antioxidant, anti-inflammatory and antiproliferative efficacy against various tumours, but the role of curcumin in gastroprotection is little studied. We determined the effect of curcumin against gastric haemorrhagic lesions induced by 75% ethanol and alterations in gastric blood flow (GBF) in rats with cyclooxygenase-1 (COX-1) and COX-2 activity inhibited by indomethacin, SC-560 or rofecoxib, inhibited NO-synthase activity, capsaicin denervation and blockade of TRPV1 receptors by capsazepine.METHODS:One hour after ethanol administration, the gastric mucosal lesions were assessed by planimetry, the GBF was examined by H2 gas clearance, plasma gastrin was determined by radioimmunoassay, and the gastric mucosal mRNA expression of Cdx-2, HIF-1α, HO-1 and SOD 2 was analysed by RT-PCR.RESULTS:Curcumin, in a dose-dependent manner, reduced ethanol-induced gastric lesions and significantly increased GBF and plasma gastrin levels. Curcumin-induced protection was completely reversed by indomethacin and SC-560, and significantly attenuated by rofecoxib, L-NNA, capsaicin denervation and capsazepine. Curcumin downregulated Cdx-2 and Hif-1α mRNA expression and upregulated HO-1 and SOD 2, and these effects were reversed by L-NNA and further restored by co-treatment of L-NNA with L-arginine.CONCLUSIONS:Curcumin-induced protection against ethanol damage involves endogenous PG, NO, gastrin and CGRP released from sensory nerves due to activation of the vanilloid TRPV1 receptor. This protective effect can be attributed to the inhibition of HIF-1α and Cdx-2 expression and the activation of HO-1 and SOD 2 expression.

Hydrogen sulfide (H2S) is an endogenous mediator, synthesized from l-cysteine by cystathionine γ-lyase (CSE), cystathionine β-synthase (CBS) or 3-mercaptopyruvate sulfurtransferase (3-MST). The mechanism(s) involved in H2S-gastroprotection against ischemia/reperfusion (I/R) lesions and their time-dependent progression into deeper gastric ulcerations have been little studied. We determined the effect of l-cysteine, H2S-releasing NaHS or slow H2S releasing compound GYY4137 on gastric blood flow (GBF) and gastric lesions induced by 30 min of I followed by 3, 6, 24 and 48 h of R. Role of endogenous prostaglandins (PGs), afferent sensory nerves releasing calcitonin gene-related peptide (CGRP), the gastric expression of hypoxia inducible factor (HIF)-1α and anti-oxidative enzymes were examined. Rats with or without capsaicin deactivation of sensory nerves were pretreated i.g. with vehicle, NaHS (18–180 μmol/kg) GYY4137 (90 μmol/kg) or l-cysteine (0.8–80 μmol/kg) alone or in combination with (1) indomethacin (14 μmol/kg i.p.), SC-560 (14 μmol/kg), celecoxib (26 μmol/kg); (2) capsazepine (13 μmol/kg i.p.); and (3) CGRP (2.5 nmol/kg i.p.). The area of I/R-induced gastric lesions and GBF were measured by planimetry and H2-gas clearance, respectively. Expression of mRNA for CSE, CBS, 3-MST, HIF-1α, glutathione peroxidase (GPx)-1, superoxide dismutase (SOD)-2 and sulfide production in gastric mucosa compromised by I/R were determined by real-time PCR and methylene blue method, respectively. NaHS and l-cysteine dose-dependently attenuated I/R-induced lesions while increasing the GBF, similarly to GYY4137 (90 μmol/kg). Capsaicin denervation and capsazepine but not COX-1 and COX-2 inhibitors reduced NaHS- and l-cysteine-induced protection and hyperemia. NaHS increased mRNA expression for SOD-2 and GPx-1 but not that for HIF-1α. NaHS which increased gastric mucosal sulfide release, prevented further progression of acute I/R injury into deeper gastric ulcers at 6, 24 and 48 h of R. We conclude that H2S-induced gastroprotection against I/R-injury is due to increase in gastric microcirculation, anti-oxidative properties and afferent sensory nerves activity but independent on endogenous prostaglandins.

Background and Purpose Carbon monoxide (CO), a gaseous mediator produced by haem oxygenases (HOs), has been shown to prevent stress‐, ethanol‐, aspirin‐ and alendronate‐induced gastric damage; however, its role in gastric ulcer healing has not been fully elucidated. We investigated whether CO released from tricarbonyldichlororuthenium (II) dimer (CORM‐2) can affect gastric ulcer healing and determined the mechanisms involved in this healing action. Experimental Approach Gastric ulcers were induced in Wistar rats by serosal application of acetic acid. Animals received 9 days of treatment with RuCl 3 [2.5 mg·kg −1 intragastrically (i.g.)], haemin (5 mg·kg −1 i.g.), CORM‐2 (0.1–10 mg·kg −1 i.g.) administered alone or with zinc protoporphyrin IX (ZnPP, 10 mg·kg −1 i.g.), 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one (ODQ, 5 mg·kg −1 i.g.), N G ‐nitro‐ l ‐arginine ( l ‐NNA, 15 mg·kg −1 i.g.), indomethacin (5 mg·kg −1 i.g.) or glibenclamide (10 mg·kg −1 i.g.). Gastric ulcer area and gastric blood flow (GBF) were assessed planimetrically, microscopically and by laser flowmeter respectively. Gastric mRNA/protein expressions of EGF, EGF receptors, VEGFA, HOs, nuclear factor (erythroid‐derived 2)‐like 2 (Nrf2), COX‐2, hypoxia‐inducible factor (HIF)‐1α and pro‐inflammatory iNOS, IL‐1β and TNF‐α were determined by real‐time PCR or Western blots. Key Results CORM‐2 and haemin but not RuCl 3 or ZnPP decreased ulcer size while increasing GBF. These effects were reduced by ODQ, indomethacin, l ‐NNA and glibenclamide. CORM‐2 significantly decreased the expression of pro‐inflammatory markers, Nrf2/HO1 and HIF‐1α, and up‐regulated EGF. Conclusions and Implications CO released from CORM‐2 or endogenously produced by the HO1/Nrf2 pathway accelerates gastric ulcer healing via an increase in GBF, an up‐regulation in EGF expression and down‐regulation of the inflammatory response.

Stress is known to cause severe adverse effects in the human gastrointestinal tract including mucosal microbleedings and erosions or even gastric ulceration but the mechanism of these complications has not been fully elucidated. The pathogenesis of stress-induced gastric damage involves the fall in Gastric Blood Flow (GBF), an increase in gastric acid secretion and gastric motility, enhanced adrenergic and cholinergic nerve activity and the rise in gastric mucosal generation of reactive oxygen species. The gastric mucosal defense mechanisms against the deleterious effect of stress include the activation of the hypothalamic-pituitary-adrenal axis which has been linked with glucocorticoids release capable of counteracting of stress-induced gastric lesions. Here we summarize the novel gastroprotective mechanisms against stress damage exhibited by angiotensin-(1-7), the newly discovered metabolite of Renin-Angiotensin System (RAS), the gaseous mediators such as nitric oxide (NO), hydrogen sulfide (H2S) or Carbon Monoxide (CO), and the food intake controlling peptides ghrelin, nesfatin- 1 and apelin possibly acting via brain-gut axis. These bioactive molecules such as RAS vasoactive metabolite angiotensin-(1-7) and appetite peptides have been shown to afford gastroprotective effect against stressinduced gastric lesions mainly mediated by an increase in gastric microcirculation. Gaseous mediators protect the gastric mucosa against stress lesions by mechanism involving the activation of PG/COX and CO/HO-1 biosynthetic pathways, and their anti-inflammatory and anti-oxidizing properties. Thus, these new components add new mechanistic aspects to the common cooperation of NO/NO-synthase, PG/COX systems and vasoactive sensory neuropeptides including CGRP but their gastroprotective efficacy against experimental stress ulcerogenesis requires the confirmation in human clinical trials.

Background and Purpose Carbon monoxide (CO), gaseous mediator produced by heme oxygenases (HO), has been shown to prevent stress-, ethanol-, aspirinor alendronate-induced gastric damage, however, its role in the gastric ulcer healing has not been fully explained. We investigated whether CO released from tricarbonyldichlororuthenium (II) dimer (CORM-2) can affect gastric ulcer healing and determined mechanisms involved in healing action of this compound.

Acetylsalicylic acid (ASA) is mainly recognized as painkiller or anti-inflammatory drug. However, ASA causes serious side effects towards gastrointestinal (GI) tract which limits its usefulness. Carbon monoxide (CO) and hydrogen sulfide (H2S) have been described to act as important endogenous messengers and mediators of gastroprotection but whether they can interact in gastroprotection against acute ASA-induced gastric damage remains unknown. In this study male Wistar rats were pretreated with 1) vehicle (saline, i.g.), 2) tricarbonyldichlororuthenium (II) dimer (CORM-2, 5mg/kg i.g.), 3) sodium hydrosulfide (NaHS, 5mg/kg i.g.), 4) zinc protoporphyrin (ZnPP, 10mg/kg i.p.), 5) D,L-propargylglycine (PAG, 30mg/kg i.g.), 6) ZnPP combined with NaHS, 7) PAG combined with CORM-2 or 8) 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10mg/kg i.p.) combined with CORM-2 or NaHS and 30min later ASA was administered i.g. in a single dose of 125mg/kg. After 1h, gastric blood flow (GBF) was determined by H2 gas clearance technique and gastric lesions were assessed by planimetry and histology. CO content in gastric mucosa and COHb concentration in blood were determined by gas chromatography and H2S production was assessed in gastric mucosa using methylene blue method. Protein and/or mRNA expression for cystathionine-γ-lyase (CSE), cystathionine-β-synthase (CBS), 3-mercaptopyruvate sulfurtransferase (3-MST), heme oxygenase (HO)-1, HO-2, hypoxia inducible factor-alpha (HIF)-1α, nuclear factor (erythroid-derived 2)-like 2 (Nrf-2), cyclooxygenase (COX)-1 and COX-2, inducible nitric oxide synthase (iNOS) and interleukin (IL)-1β were determined by Western blot or real-time PCR, respectively. ASA caused hemorrhagic gastric mucosal damage and significantly decreased GBF, H2S production, CO content, mRNA or protein expression for CSE, 3-MST, HO-2 and increased mRNA and/or protein expression for CBS, HO-1, Nrf-2, HIF-1α, iNOS, IL-1β, COX-2 in gastric mucosa and COHb concentration in blood. Pretreatment with CORM-2 or NaHS but not with PAG decreased ASA-damage and increased GBF. ZnPP reversed protective and hyperemic effect of NaHS but PAG failed to affect CORM-2-induced gastroprotection. CORM-2 elevated CO content, mRNA or protein expression for HO-1, Nrf-2, and decreased expression of CBS, HIF-1α, COX-2, IL-1β, iNOS, the H2S production in gastric mucosa and COHb concentration in blood. NaHS raised mRNA or protein expression for CSE, COX-1 and decreased mRNA expression for IL-1β and COHb level in blood. We conclude that CO is involved in gastroprotection induced by H2S while beneficial protective action of CO released from CORM-2 in gastric mucosa seems to be H2S-independent. In contrast to H2S, CO ameliorates hypoxia, regulates Nrf-2 expression but similarly to H2S acts on sGC-dependent manner to restore gastric microcirculation and exhibit anti-inflammatory activity in gastric mucosa compromised by ASA.

Background Stress of different origin is known to alter so called “brain-gut axis” and contributes to a broad array of gastrointestinal disorders including inflammatory bowel disease (IBD), irritable bowel syndrome (IBS) and other functional gastrointestinal diseases. The stressful situations and various stressors including psychosocial events, heat, hypo- and hyperthermia may worsen the course of IBD via unknown mechanism. The aims of this paper were to provide an overview of experimental and clinical evidences that stress activates the brain-gut axis which results in a mucosal mast cells activation and an increase in the production of proinflammatory cytokines and other endocrine and humoral mediators. Methods Research and online content related to effects of stress on lower bowel disorders are reviewed and most important mechanisms are delineated. Results Brain conveys the neural, endocrine and circulatory messages to the gut via brain-gut axis reflecting changes in corticotrophin releasing hormone, mast cells activity, neurotransmission at the autonomic nerves system and intestinal barrier function all affecting the pathogenesis of animal colitis and human IBD. Stress triggers the hypothalamus-pituitary axis and the activation of the autonomic nervous system, an increase in cortisol levels and proinflammatory cytokines such as tumor necrosis factor-alpha, interleukin-8, interleukin-1beta and interleukin-6. Conclusion The acute or chronic stress enhances the intestinal permeability weakening of the tight junctions and increasing bacterial translocation into the intestinal wall. An increased microbial load in the colonic tissue, excessive cytokine release and a partially blunted immune reactivity in response to stress result in its negative impact on IBD.

Carbon monoxide (CO) produced by heme oxygenase (HO)-1 and HO-2 or released from the CO-donor, tricarbonyldichlororuthenium (II) dimer (CORM-2) causes vasodilation, with unknown efficacy against stress-induced gastric lesions. We studied whether pretreatment with CORM-2 (0.1–10 mg/kg oral gavage (i.g.)), RuCl3 (1 mg/kg i.g.), zinc protoporphyrin IX (ZnPP) (10 mg/kg intraperitoneally (i.p.)), hemin (1–10 mg/kg i.g.) and CORM-2 (1 mg/kg i.g.) combined with NG-nitro-l-arginine (l-NNA, 20 mg/kg i.p.), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, 10 mg/kg i.p.), indomethacin (5 mg/kg i.p.), SC-560 (5 mg/kg i.g.), and celecoxib (10 mg/kg i.g.) affects gastric lesions following 3.5 h of water immersion and restraint stress (WRS). Gastric blood flow (GBF), the number of gastric lesions and gastric CO and nitric oxide (NO) contents, blood carboxyhemoglobin (COHb) level and the gastric expression of HO-1, HO-2, hypoxia inducible factor 1α (HIF-1α), tumor necrosis factor α (TNF-α), cyclooxygenase (COX)-2 and inducible NO synthase (iNOS) were determined. CORM-2 (1 mg/kg i.g.) and hemin (10 mg/kg i.g.) significantly decreased WRS lesions while increasing GBF, however, RuCl3 was ineffective. The impact of CORM-2 was reversed by ZnPP, ODQ, indomethacin, SC-560 and celecoxib, but not by l-NNA. CORM-2 decreased NO and increased HO-1 expression and CO and COHb content, downregulated HIF-1α, as well as WRS-elevated COX-2 and iNOS mRNAs. Gastroprotection by CORM-2 and HO depends upon CO’s hyperemic and anti-inflammatory properties, but is independent of NO.

Hydrogen sulfide (H 2 S) modulates a number of physiological actions including vasodilatation, inhibition of oxidant stress and apoptosis.H 2 S which is formed in gastric epithelium by the activity of two enzymes cysthationine γ-lyase (CSE) and cystathionine β-synthetase (CBS) has been shown to protect the gastric mucosa from ethanol-induced gastric lesions but whether its efficacy against acid-dependent stress-induced damage has been little studied.It also remains unknown how the expression of CSE and CBS contribute to the mucosal damage induced by stress in the presence or absence of H 2 S. We studied the effect of NaHS, a H 2 S-donor and L-cysteine, a H 2 S precursor on 1) gastric acid secretion in rats equipped with chronic gastric fistulas (GF) and water immersion restraint stress (WRS)-induced gastric lesions with intact and capsaicin-denervated sensory nerves (large dose 125 mg/kg s.c for 3 days).Rats were pretreated 30 min before the WRS with A) NaHS (5 mg/kg i.g); B) Lcysteine (10 mg/kg i.g.) with or without the combination with inhibitors of CSE activity, beta-cyano-L-alanine (BCA, 50 mg/kg i.g.) and D,L-propargylglycine (PAG 15 -80 mg/kg i.g.).The number of gastric lesions was measured by planimetry, the gastric blood flow (GBF) by H 2 -gas clearance technique and the mRNA expression of CSE, CBS, HIF-1 α and antioxidizing enzymes SOD and GPx was assessed by RT-PCR and Western Blot.NaHS (1-20 mg/kg) and cysteine (5-40 mg/kg) dose-dependently inhibited basal and histaminestimulated gastric acid secretion in GF rats.Exposure to WRS caused mucosal hemorrhagic lesions accompanied by the fall in GBF and upregulation of mRNA expression of CSE and CBS.Pretreatment with NaHS and L-cysteine significantly reduced WRS-induced gastric damage and significantly raised GBF and these effects were completely lost in animals with capsaicin denervation.BCA and PAG which dose-dependently augmented the number of WRS lesions, reversed the NaHS and L-cysteine-induced protection and hyperemia against WRS-induced gastric damage.Upregulation of mRNA expression for HIF-1 α mRNA, CSE and CBS in the gastric mucosa exposed to WRS was diminished by NaHS and L-cysteine and these effects were further enhanced in capsaicin-denervated rats treated with NaHS and L-cysteine.The increased expression of SOD and GPx mRNA was observed in NaHS-and L-cysteine-pretreated rats but not in those with capsaicin-denervation.We conclude that: 1) an increase in the expression of CSE and CBS, key enzymes in H 2 S biosynthesis, could compensate for the stress-induced impairment of gastric mucosal defense; 2) antisecretory activity of H 2 S donors contributes to the attenuation of acid-dependent injury caused by WRS, and 3) sensory mediators and antioxidizing enzymes SOD and GPx play an important role in H 2 S-induced gastroprotection against WRS-induced ulcerogenesis.