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As a multifunctional signaling molecule, hydrogen sulfide (H2S) has been reported to induce plant responses to a variety of abiotic stresses. However, there are no reports on H2S treatment inducing resistance in apples against Penicillium expansum, a biotic factor, and its possible mechanism of action. In this study, fumigating apples with 5 mM sodium hydrosulfide (NaHS), the exogenous donor of H2S, for 12 h reduced the diameter of lesions in fruit colonized by P. expansum. NaHS treatment markedly promoted the synthesis of endogenous H2S, hydrogen peroxide (H2O2), and nitrogen oxide (NO). In vivo NaHS treatment enhanced the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, p-coumarate:coenzyme A ligase isoenzymes, caffeoyl-CoA-O-methyltransferase, caffeic acid-O-methyltransferase, ferulic acid-5-hydroxylase, cinnamyl-CoA reductase, and cinnamyl-alcohol dehydrogenase. The treatment also facilitated the production of specific phenolic acids, such as cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid, and sinapic acid; total phenolic compounds; p-coumaryl alcohol; coniferyl alcohol; sinapyl alcohol; and lignin. NaHS treatment induced resistance against P. expansum in apples through H2O2- and NO-mediated activation of phenylpropanoid metabolism.

The use of cyclosporine A (CsA) in transplant recipients is limited due to its side effects of causing severe hypertension. We have previously shown that CsA increases the activity of the epithelial sodium channel (ENaC) in cultured distal nephron cells. However, it remains unknown whether ENaC mediates CsA-induced hypertension and how we could prevent hypertension. Our data show that the open probability of ENaC in principal cells of split-open cortical collecting ducts was significantly increased after treatment of rats with CsA; the increase was attenuated by lovastatin. Moreover, CsA also elevated the levels of intracellular cholesterol (Cho), intracellular reactive oxygen species (ROS) via activation of NADPH oxidase p47phox, serum- and glucocorticoid-induced kinase isoform 1 (Sgk1), and phosphorylated neural precursor cell–expressed developmentally downregulated protein 4–2 (p-Nedd4-2) in the kidney cortex. Lovastatin also abolished CsA-induced elevation of α-, ß-, and γ-ENaC expressions. CsA elevated systolic blood pressure in rats; the elevation was completely reversed by lovastatin (an inhibitor of cholesterol synthesis), NaHS (a donor of H2S which ameliorated CsA-induced elevation of reactive oxygen species), or amiloride (a potent ENaC blocker). These results suggest that CsA elevates blood pressure by increasing ENaC activity via a signaling cascade associated with elevation of intracellular ROS, activation of Sgk1, and inactivation of Nedd4-2 in an intracellular cholesterol-dependent manner. Our data also show that NaHS ameliorates CsA-induced hypertension by inhibition of oxidative stress.

Objectives. Acute pancreatitis (AP) is a life-threatening condition. Using antioxidants in AP is insufficient and conflicting. Therefore, this study compared the effect of hydrogen sulfide (H2S) donor, sodium hydrosulfide (NaHS), leptin or curcumin pretreatment on AP induced by L-arginine. Methods. Forty adult male rats were used and classified into: 1) control; 2) AP group [each rat was intraperitoneally (i.p.) injected with 2 doses of L-arginine of 250 mg/100 g body weight (b.w.) with an interval of 1 h]; 3) NaHS+AP group (each rat was i.p. injected with 10 mg/kg b.w. of NaHS 1 h before induction of AP); 4) leptin+AP group (each rat was pretreated with 10 μg/kg b.w. of leptin 30 min before induction of AP; and 5) curcumin+AP group (in which rats were i.p. injected with 150 mg/kg b.w. of curcumin 30 min before induction of AP). Serum amylase, lipase, nitric oxide (NO), tumor necrosis factor alpha (TNF-α), and corticosterone (CORT) levels were assayed. In addition, pancreatic tissues were obtained for histopathological examination and malondialde-hyde (MDA), total antioxidant capacity (TAC), and inducible nitric oxide synthase (iNOS) levels were measured. Results. All AP treated groups showed significant decrease in serum levels of pancreatic enzymes, NO, and TNF-α, and pancreatic MDA and iNOS levels, while TAC levels were significantly increased. NaHS caused more limitation of inflammation than leptin and curcumin by affecting iNOS. Leptin was more potent than curcumin due to the stimulatory effect of leptin on glucocorticoid release to counteract inflammation. Conclusions. NaHS was more effective in AP amelioration than the leptin and curcumin.

Aims Hydrogen sulfide (H2S) is shown in ocular tissues and suggested to involve in the regulation of retinal circulation. However, the mechanism of H2S-induced relaxation on retinal artery is not clarified yet. Herein, we aimed to evaluate the role of several calcium (Ca2+) signaling and Ca2+ sensitization mechanisms in the relaxing effect of H2S donor, NaHS, on retinal arteries. Materials and methods Relaxing effects of NaHS (10−5–3 × 10−3M) were determined on precontracted retinal arteries in Ca2+ free medium as well as in the presence of the inhibitors of Ca2+ signaling and Ca2+ sensitization mechanisms. Additively, Ca2+ sensitivity of the contractile apparatus were evaluated by CaCl2-induced contractions in the presence of NaHS (3 × 10−3M). Functional experiments were furtherly assessed by protein and/or mRNA expressions, as appropriate. Key findings The relaxations to NaHS were preserved in Ca2+ free medium while NaHS pretreatment decreased the responsiveness to CaCl2. The inhibitors of plasmalemmal Ca2+-ATPase, sarcoplasmic-endoplasmic reticulum Ca2+-ATPase, Na+-Ca2+ ion-exchanger and myosin light chain kinase (MLCK) unchanged the relaxations to NaHS. Likewise, Ca2+ sensitization mechanisms including, rho kinase, protein kinase C and tyrosine kinase were unlikely to mediate the relaxation to NaHS in retinal artery. Whereas, a marked reduction was determined in NaHS-induced relaxations in the presence of MLCP inhibitor, calyculin A. Supportively, NaHS pretreatment significantly reduced phosphorylation of MYPT1-subunit of MLCP. Significance The relaxing effect of NaHS in retinal artery is likely to be related to the activation of MLCP and partly, to decrement in Ca2+ sensitivity of contractile apparatus.

Background: Hydrogen sulfide (H2S) has been shown to have a protective role in various kidney disorders. Objectives: This study investigated the molecular mechanism of NaHS (a H2S donor) in treating on the renal damage induced by cisplatin (CP). Materials and Methods: Thirty-two male rats were randomly divided into 4 groups: Normal control group (group A)‚ NaHS group (group B) which received 200 µg/kg/d (intraperitoneal injection; i.p.) for 15 days‚ CP group (group C) which rats were injected with CP (5 mg/kg, single dose, i.p.), and CP + NaHS group (group D) (5 mg/kg and 200 µg/kg, respectively, i.p.). Samples of urine and serum, tissue of kidney were collected for analysis after treatments for 15 days. Morphological changes were elevated under light microscope‚ protein expression of desmin and nephrin were determined by immunohistochemistry and western blotting and also malondialdehyde (MDA) level was determined by spectrophotometer. Results: Compared to the CP group, NaHS treatment mitigated histological damages, decreased 24-hour urine protein excretion, serum urea and creatinine as well as MDA level. NaHS treatment increased protein levels of nephrin. Moreover, NaHS treatment decreased protein levels of desmin. Conclusions: NaHS can ameliorate CP -induced renal damage in rats which is associated with the increase in nephrin protein expression, and the decrease in MDA level and desmin protein expression.

Stem cell therapy represents a promising therapeutic avenue for cardiac disorders, including heart failure. Although stem cell transplantation showed encouraging preliminary results, the outcomes of clinical studies are still unsatisfactory. This study aimed to compare the outcomes of two therapeutic approaches, in vivo co-delivery of sodium hydrogen sulfide (NaHS) concomitant with bone marrow-derived mesenchymal stem cell (BMSC) transplantation and in vitro preconditioning of BMSCs with NaHS, both of which are intended to promote the success of stem cell therapy in rats with isoprenaline-induced heart failure. Heart failure developed 4 weeks after the subcutaneous injection of isoprenaline (170 mg/kg) for 4 consecutive days. The in vivo approach involved the co-delivery of intraperitoneally administered NaHS concomitant with BMSC transplantation for a period of 14 days. The in vitro approach involved preconditioning BMSCs with NaHS for 30 min before transplantation. Compared to treatment with BMSCs alone, in vitro preconditioning of BMSCs with NaHS improved left ventricular function as measured by echocardiography and electrocardiography and enhanced stem cell homing, proliferation and differentiation as manifested by higher cardiac expression of GATA-4 and myocyte enhancer factor 2. Moreover, the measurement of cardiac transforming growth factor beta 1 levels and histopathological investigation revealed mitigated fibrosis and myocardial injury scores. Compared with BMSC therapy alone, the in vivo approach enhanced stem cell homing and differentiation, alleviated fibrosis and augmented vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expression. In conclusion, NaHS can potentiate the efficiency of BMSC therapy for heart failure by in vitro preconditioning or in vivo co-delivery. The in vitro approach is superior with regard to improving cardiac function in addition to enhancing stem cell proliferation, while the in vivo approach is superior with regard to increasing cardiac VEGF and eNOS expression.

Introduction and aim: Hydrogen sulfide (H 2 S) is an endogenously produced gas-structure mediator. It is proposed to have antioxidant, anti-inflammatory and antiapoptotic effects. Acetaminophen (N-acetyl-P-aminophenol; APAP) is an antipyretic and analgesic medication known as paracetamol. When taken at therapeutic doses there are few side-effects, but at high doses APAP can cause clear liver and kidney damage in humans and experimental animals. In this study, the effects of the H 2 S donor of sodium hydrosulfide (NaHS) on acute renal toxicity induced by APAP in rats were researched in comparison with N-acetyl cysteine (NAC). Method: Rats were divided into six groups (n = 7) as control. APAP, APAP + NAC, APAP + NaHS 25 µmol/kg, NaHS 50 µmol/kg and NaHS 100 µmol/kg. After oral dose of 2 g/kg APAP, NAC and NaHS were administered via the i.p. route for 7 days. In renal homogenates, KIM-1 (Kidney Injury Molecule-1), NGAL (neutrophil gelatinase-associated lipocalin), TNF-? and TGFß levels were measured with the ELISA method for tissue injury and inflammation. In renal tissue, oxidative stress levels were identified by spectrophotometric measurement of TAS and TOS. Histopathologic investigation of renal tissue used caspase 3 staining for apoptotic changes, Masson trichrome and H&E staining for variations occurring in glomerular and tubular systems. Results: NaHS lowered KIM-1, NGAL, TNF-?, TGF-ß and TOS levels elevated in renal tissue linked to APAP and increased TAS values. NaHS prevented apoptosis in the kidney and was identified to ensure histologic amelioration in glomerular and tubular structures. NaHS at 50 µmol/kg dose was more effective, with the effect reduced with 100 µmol/kg dose. Conclusion: H 2 S shows protective effect against acute renal injury linked to APAP. This protective effect reduces with high doses of H 2 S. The anti-inflammatory and antioxidant activity of H 2 S may play a role in the renoprotective effect. © 2019, Springer Nature B.V.

Background: In contrast to its role as poison, hydrogen sulfide (H 2 S) is recently considered as a gaso-transmitter which mediates important physiologic functions in humans. Evidence is accumulating to demonstrate that inhibitors of H 2 S production or therapeutic H 2 S donor compounds exert significant effects in various experimental models. Carbonic anhydrases (CA) are a group of zinc-containing metalloenzymes that catalyse the reversible hydration of carbon dioxide. CAs activity in erythrocytes (CAI and CAII) has recently been observed to be associated with various pathological conditions especially in diabetes mellitus, hypertension and lipid disorders. Alteration of this enzyme activity has been reported by the effect of advanced glycation end products methylglyoxal and reduced glutathione. Aims and Objectives : As H 2 S, being a mediator of many physiological functions and synthesized in vivo, may affect functions of many intracellular proteins like carbonic anhydrase, the objective of this study is to find out if there is any change in the carbonic anhydrase activity under the effect of H 2 S- donor NaHS in dose dependant manner using RBC model in vitro. Materials and Methods: Blood sample was collected from forty (40) numbers of healthy volunteers of 18-40 years of in heparin containing vials and packed cells were prepared immediately by centrifugation The packed erythrocytes were washed three times with normal saline and diluted (1:10) with the normal saline. One ml each of diluted packed cells was taken in eight test tubes. Serial dilutions of NaHS (1to 250 µMol/L) was added to all the test tubes except for the first test tube where only normal saline was added and incubated at room temperature for one hour. Haemolysates was prepared from the erythrocytes with equal volume of distilled water in each tube and the CA activity was determined in the haemolysates using standardized method. Results: There is significant increase of CA activity in dose dependent manner under the effect of NaHS and also compared to the activity of hemolysate prepared without NaHS. Conclusions: Our study for the first time demonstrated that the Carbonic Anhydrase activity of erythrocytes is significantly increases by the effect of NaHS and this study reveals some important biological role of H2S and carbonic anhydrase. Asian Journal of Medical Sciences Vol. 7(3) 2016 23-27

Non-invasive micro-test techniques (NMT) were used to analyze NaCl-altered flux profiles of K+, Na+, and H+ in roots and effects of NaHS (a H2S donor) on root ion fluxes in two contrasting poplar species, Populus euphratica (salt-resistant) and Populus popularis (salt-sensitive). Both poplar species displayed a net K+ efflux after exposure to salt shock (100 mM NaCl), as well as after short-term (24 h), and long-term (5 d) saline treatment (50 mM NaCl, referred to as salt stress). NaHS (50 M) restricted NaCl-induced K+ efflux in roots irrespective of the duration of salt exposure, but K+ efflux was not pronounced in data collected from the long-term salt stress treatment of P. euphratica. The NaCl-induced K+ efflux was inhibited by a K+ channel blocker, tetraethylammonium chloride (TEA) in P. popularis root samples, but K+ loss increased with a specific inhibitor of plasma membrane H+-ATPase, sodium orthovanadate, in both poplar species under long-term salt stress and NaHS treatment. This indicates that NaCl-induced K+ loss was through depolarization-activated K+ channels. NaHS caused increased Na+ efflux and a corresponding increase in H+ influx for poplar roots subjected to both the short- and long-term salt stress. The NaHS-enhanced H+ influx was not significant in P. euphratica samples subjected to short term salt stress. Both sodium orthovanadate and amiloride (a Na+/H+ antiporter inhibitor) effectively inhibited the NaHS-augmented Na+ efflux, indicating that the H2S-enhanced Na+ efflux was due to active Na+ exclusion across the plasma membrane. We therefore conclude that the beneficial effects of H2S probably arise from upward regulation of the Na+/H+ antiport system (H+ pumps and Na+/H+ antiporters), which promote exchange of Na+ with H+ across the plasma membrane and simultaneously restricted the channel-mediated K+ loss that activated by membrane depolarization.

Background/Aims: Stroke is among the top causes of death worldwide. Neuroprotective agents are thus considered as potentially powerful treatment of stroke. Methods: Using both HT22 cells and male Sprague-Dawley rats as in vitro and in vivo models, we investigated the effect of NaHS, an exogenous donor of H2S, on the focal cerebral ischemia-reperfusion (I/R) induced brain injury. Results: Administration of NaHS significantly decreased the brain infarcted area as compared to the I/R group in a dose-dependent manner. Mechanistic studies demonstrated that NaHS-treated rats displayed significant reduction of malondialdehyde content, and strikingly increased activity of superoxide dismutases and glutathione peroxidase in the brain tissues compared with I/R group. The enhanced antioxidant capacity as well as restored mitochondrial function are NaHS-treatment correlated with decreased cellular reactive oxygen species level and compromised apoptosis in vitro or in vivo in the presence of NaHS compared with control. Further analysis revealed that the inhibition of PARP-1 cleavage and AIF translocation are involved in the neuroprotective effects of NaHS. Conclusion: Collectively, our results suggest that NaHS has potent protective effects against the brain injury induced by I/R. NaHS is possibly effective through inhibition of oxidative stress and apoptosis.

Brain ischemia leads to poor oxygen supply, and is one of the leading causes of brain damage and/or death. Neuroprotective agents are thus in great need for treatment purpose. Using both young and aged primary cultured hippocampal neurons as in vitro models, we investigated the effect of sodium hydrosulfide (NaHS), an exogenous donor of hydrogen sulfide (H2S), on oxygen-glucose deprivation (OGD) damaged neurons that mimick focal cerebral ischemia/reperfusion (I/R) induced brain injury. NaHS treatment (250 μM) protected both young and aged hippocampal neurons, as indicated by restoring number of primary dendrites by 43.9% and 68.7%, number of dendritic end tips by 59.8% and 101.1%, neurite length by 36.8% and 66.7%, and spine density by 38.0% and 58.5% in the OGD-damaged young and aged neurons, respectively. NaHS treatment inhibited growth associated protein 43 (GAP-43) downregulation, oxidative stress in both young and aged hippocampal neurons following OGD damage. Further studies revealed that NaHS treatment could restore ERK1/2 activation, which was inhibited by OGD-induced protein phosphatase 2 (PP2A) upregulation. Our results demonstrated that NaHS has potent protective effects against neuron injury induced by OGD in both young and aged hippocampal neurons.

Hydrogen sulphide (H2S) is produced endogenously via two enzymes dependent on pyridoxal phosphate (PLP): cystathionine beta-synthase (CBS, EC 4.2.1.22), cystathionase γ-liase (CTH, EC 4.4.1.1), and a third, 3-mercaptopyruvate sulfurtransferase (MPST, EC 2.8.1.2). H2S strengthens the defence mechanisms of the gastric mucosal barrier, and plays an important role in gastroprotection, including the increased resistance to damage caused by various irritants and non-steroidal anti-inflammatory drugs. The study was conducted to determine the role of H2S in ulcerated gastric mucosa of rats caused by immobilization in cold water (WRS). The activity and expression of γ-cystathionase, cystathionine β-synthase, 3-mercaptopyruvate sulfurtransferase, and rhodanese was compared with healthy mucosa, together with H2S generation, and cysteine, glutathione, and cystathionine levels. The results showed that the defence mechanism against stress is associated with stimulation of the production of H2S in the tissue and confirmed the observed advantageous effect of H2S on healing of gastric ulcers. In case of animals pretreated with exogenous sources of H2S and NaHS, and some changes observed in the ulcerated gastric mucosa tend to return to values found in the healthy tissue, a finding that is in accordance with the previously determined gastroprotective properties of H2S. The results presented in this paper point to the possible role of rhodanese in H2S production in the gastric mucosa of rats, together with the earlier mentioned three enzymes, which are all active in this tissue.

The aim of the study was to investigate the protective effects of sodium hydrosulfide (NaHS), a H2S donor, against hypoxia-induced injury in human umbilical vein endothelial cells (HUVECs) and also to look into the possible mechanisms by which H2S exerts this protective effect. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and scratch wound healing assay were chosen to measure the cell viability and migration-promoting effects. The fluorescent probe, DCFH-DA and 5,5',6,6'-Tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) were applied to detect the reactive oxygen species (ROS) level and mitochondrial membrane potential (ΔΨm). Furthermore, western blots were used to measure the expressions of the apoptosis-related proteins. Under hypoxic conditions, 300 μM and 600 μM of H2S could protect HUVECs against hypoxia-induced injury, as determined by MTT assay. Following the treatment of 60 µM NaHS for 18 h, scratch wound healing assays indicated that the scratch became much narrower than control group. After treatment with 60 µM, 120 µM, and 600 µM NaHS, and hypoxia for 30 min, flow cytometry demonstrated that the ROS concentrations decreased to 95.08% ± 5.52%, 73.14% ± 3.36%, and 73.51% ± 3.05%, respectively, compared with the control group. In addition, the JC-1 assay showed NaHS had a protective effect on mitochondria damage. Additionally, NaHS increased Bcl-2 expression and decreased the expression of Bax, Caspase-3 and Caspase-9 in a dose-dependent way. Our results suggest that H2S can protect endothelial cells and promote migration under hypoxic condition in HUVECs. These effects are partially associated with the preservation of mitochondrial function mediated by regulating the mitochondrial-dependent apoptotic pathway.

Hydrogen sulfide (H2S) is commonly known as a toxic gas with an unpleasant odor. However, in the human body it plays a role as a gaseous transmitter involved in the control of physiological processes. Studies published so far have shown that H2S increased synaptic long-term potentiation in the central nervous system and exerted the inflammatory and anti-inflammatory effects on vascular endothelium. These effects clearly depend on the concentration of this gaseous molecule. H2S exerts vasodilatory effect in the cardiovascular system similar to those exhibited by carbon monoxide or nitric oxide. It is believed that H2S may play a potential role in the physiology of the gastrointestinal tract including the mechanism of gastroprotection of gastric mucosa and possibly exerts a protective effect in other parts of the digestive system. The administration of L-cysteine, the precursor of H2S or NaHS, the exogenous donor of this gaseous molecule, significantly reduced gastric damage induced by ethanol, an agent that is known to induce acute gastric damage and hemorrhagic necrosis to the gastric mucosa. The administration of H2S results in increased secretion of protective bicarbonate and mucus secretions and these effects could, in part, explain the H2S-induced protection of duodenal mucosa against the damage induced by gastric acid. Despite these promising results, little is known about the therapeutic efficacy of H2S in relation to two other important gases, nitric oxide and carbon monoxide, and future studies are definitely needed to assess its usefulness in the treatment of upper and lower gastrointestinal tract disorders.

Oxidative stress is implicated in the pathogenesis of necrotizing enterocolitis (NEC). Hydrogen sulfide (H2S) has been reported to have a protective function against oxidative stress in the gut. We hypothesize that administration of H2S can help decrease intestinal epithelial cell injury in vitro.Intestinal epithelial cells (IEC-18) were treated with 200μM hydrogen peroxide (H2O2) for 21h. At 21h sodium hydrosulfide (NaHS), an H2S donor, was administered as a rescue treatment at two different concentrations: 0.1mM and 0.2mM. At 24h, cell viability was measured using a colorimetric assay (MTT). Oxidative stress was studied by glutathione peroxidase (GPx) activity and thiobarbituric acid reactive substances (TBARS). IL-6 and TNFα levels were tested to study inflammation. Data were presented as mean±SD and compared using one-way ANOVA with Bonferroni post-test.Compared to control, H2O2-treated IEC-18 had reduced viability (p0.01), lower GPx activity (p0.01), higher TBARS levels (p0.01), and increased IL6 and TNFα (p0.001). Compared to H2O2-treated IEC-18, treatment with 0.2mM NaHS rescued viability (p0.01), increased GPx activity (p0.05), and reduced TBARS (p0.01), IL6 and TNFα (p0.001).H2S successfully rescues epithelial cell damage induced by oxidative stress in vitro. This indicates that H2S could be a potential pharmacological intervention in conditions like NEC.

The recovery of phosphorus from sewage and sludge treatment systems is particularly important because it is a limited resource and a large proportion of the phosphorus currently used in Japan must be imported. We have been experimentally evaluating recovery methods with sulphide. In this study, we focussed on the extraction of phosphate from the sludge, and sought to achieve a greater extraction efficiency and to validate the extraction mechanism. We conducted three experiments, i.e. a sludge-type experiment, a coagulant ratio of pre-coagulated sludge experiment, and a concentration of pre-coagulated sludge experiment. Phosphate was extracted not with normal sewage sludge but with pre-coagulated sludge and FePO4 reagent at S/Fe=1.0–2.0. A coagulant ratio of 23 mg Fe L−1 was required in the pre-coagulation process to effectively extract phosphate. A high concentration of pre-coagulated sludge was required for the phosphate extraction. The mass balance was calculated, and 44.0% of phosphorus was extracted to supernatant, and 98.5% of iron and 98.3% of sulphur (44.1% of sulphur was sulphide). Thus, phosphate can be selectively separated from iron by the phosphate extraction method with NaHS, and phosphorus and iron can be recovered and reused at sewage treatment plants using ferric chloride as a coagulant.

Ping Cheng,* Kan Chen,* Yujing Xia, Weiqi Dai, Fan Wang, Miao Shen, Chengfen Wang, Jing Yang, Rong Zhu, Huawei Zhang, Jingjing Li, Yuanyuan Zheng, Junshan Wang, Yan Zhang, Jie Lu, Yingqun Zhou, Chuanyong GuoDepartment of Gastroenterology, Shanghai Tenth People's Hospital, Tongji University of Medicine, Shanghai, People's Republic of China *These authors contributed equally to this work Background: Hydrogen sulfide (H2S) is known to exert anti-inflammatory properties. Apoptosis and autophagy play important roles in concanavalin A (Con A)-induced acute hepatitis. The purpose of this study was to explore both the effect and mechanism of H2S on Con A-induced acute hepatitis. Methods: BALB/c mice were randomized into sham group, Con A-injection group, and 14 µmol/kg of sodium hydrosulfide (NaHS, an H2S donor) pretreatment group. Results: Aspartate aminotransferase, alanine aminotransferase, and pathological damage were significantly ameliorated by NaHS pretreatment. NaHS pretreatment significantly reduced the levels of interleukin-6 and tumor necrosis factor-α compared with those of the Con A group. The expression of Bcl-2, Bax, Beclin-1, and LC3-2, which play important roles in the apoptosis and autophagy pathways, were also clearly affected by NaHS. Furthermore, NaHS affected the p-mTOR and p-AKT. Conclusion: H2S attenuates Con A-induced acute hepatitis by inhibiting apoptosis and autophagy, in part, through activation of the PtdIns3K-AKT1 signaling pathway. Keywords: NaHS, apoptosis, PtdIns3K-AKT, autophagy

Background and aims Hydrogen sulfide (H2S), together with nitric oxide (NO) and carbon monoxide (CO), belongs to a family of endogenous signaling mediators termed “gasotransmitters”. Recent studies suggest that H2S modulates many cellular processes and it has been recognized to play a central role in inflammation, in the cardiovascular and nervous systems. By infecting monocytes/macrophages with Mycoplasma fermentans (M.F.), a well-known pro-inflammatory agent, we evaluated the effects of H2S. Methods M.F.-infected cells were analyzed by ELISA and real time RT-PCR to detect the M.F. effects on MCP-1 and on MMP-12 expression. The role of two different H2S donors (NaHS and GYY4137) on MF-infected cells was determined by treating infected cells with H2S and then testing the culture supernatants for MCP-1 and on MMP-12 production by ELISA assay. In order to identify the pathway/s mediating H2S- anti-inflammatory activity, cells were also treated with specific pharmaceutical inhibitors. Cytoplasmic and nuclear accumulation of NF-κB heterodimers was analyzed. Results We show that H2S was able to reduce the production of pro-inflammatory cytokine MCP-1, that was induced in monocytes/macrophages during M.F. infection. Moreover, MCP-1 was induced by M.F. through Toll-like receptor (TLR)-mediated nuclear factor-κB (NF-κB) activation, as demonstrated by the fact that TLR inhibitors TIRAP and MyD88 and NF-κB inhibitor IKK were able to block the cytokine production. In contrast H2S treatment of M.F. infected macrophages reduced nuclear accumulation of NF-κB heterodimer p65/p52. Conclusions Our data demonstrate that under the present conditions H2S is effective in reducing Mycoplasma-induced inflammation by targeting the NF-κB pathway. This supports further studies for possible clinical applications.