Hydrogen sulfide is one of the most important signal transduction molecules in the body. Its anabolism and catabolism in the gastrointestinal tract(GT) are extremely high, and its role in the physiological and pathological process of the GT is fairly complicated. The study reviewed recent literature on hydrogen sulfide and GT, and proposed that hydrogen sulfide exerted dual modulating effects in the GT; specifically, it promoted the functions of the GT at low concentrations while damaged the GT at high concentrations. Hydrogen sulfide donors or metabolic modifiers exerted their therapeutic effects by restoring the metabolic homeostasis of hydrogen sulfide, and extended their efficacy to other tissues through hydrogen sulfide related gut-axis. Additionally, drugs could deviate hydrogen sulfide metabolism from the normal state due to their instability of structure, local over exposure and/or excessive pharmacological effects, thus inducing toxic and side effects or transforming therapeutic effects into toxic and side effects. This study provided references for the deep research on physiological and pathological mechanisms of hydrogen sulfide and facilitated the development of hydrogen sulfide-related drugs and discovery of their toxicity and efficacy mechanism.
Gastrointestinal Tract ; Hydrogen Sulfide/pharmacology* ; Signal Transduction

The purpose of the present study is to investigate the effect of L-cysteine on colonic motility and the underlying mechanism. Immunohistochemical staining and Western blot were used to detect the localization of the HS-generating enzymes cystathionine-β-synthase (CBS) and cystathionine-γ-lyase (CSE). Organ bath system was used to observe the muscle contractile activities. Whole-cell patch-clamp technique was applied to record ionic channels currents in colonic smooth muscle cells. The results showed that both CBS and CSE were localized in mucosa, longitudinal and circular muscle and enteric neurons. L-cysteine had a dual effect on colonic contraction, and the excitatory effect was blocked by pretreatment with CBS inhibitor aminooxyacetate acid (AOAA) and CSE inhibitor propargylglycine (PAG); L-cysteine concentration-dependently inhibited L-type calcium channel current (I) without changing the characteristic of L-type calcium channel (P < 0.01); In contrast, the exogenous HS donor NaHS increased I at concentration of 100 μmol/L, but inhibited I and modified the channel characteristics at concentration of 300 μmol/L (P < 0.05); Furthermore, L-cysteine had no effect on large conductance calcium channel current (I), but NaHS significantly inhibited I (P < 0.05). These results suggest that L-cysteine has a potential dual effect on colonic smooth muscle and the inhibitory effect might be directly mediated by L-type calcium channel while the excitatory effect might be mediated by endogenous HS.
Cystathionine beta-Synthase ; Cystathionine gamma-Lyase ; Cysteine ; pharmacology ; Hydrogen Sulfide ; Muscle, Smooth

Objective: To investigate the effects of exogenous hydrogen sulfide (H₂S) on pulmonary vascular reactivity induced by endotoxic shock (ES) in rabbits. Methods: In this experiment, the model of endotoxic shock (ES) was induced by injection of lipopolysaccharides (LPS) to New Zealand big eared white rabbit through jugular vein (8 mg/0.8 ml/kg), the intervention was performed by H₂S donor(sodium hydrosulfide, NaHS) which was injected intraperitoneally (28 μmol/kg) 15 min in advance. New Zealand rabbits were randomly divided into 4 groups(n=8):control group, LPS group, LPS+NaHS group and NaHS group. The changes of mean arterial pressure (MAP) and mean pulmonary arterial pressure (MPAP) were detected. The tension of pulmonary artery ring (PARs) was detected byin vitro vascular ring technique. The ultrastructure of pulmonary artery wall and pulmonary artery endothelial cells were observed by light microscope and scanning electron microscope. Results: ①MAP was decreased while MPAP was increased in rabbits after LPS injection, and ES animal model was established successfully. Compared with LPS group, mPAP of rabbit in LPS+NaHS group was decreased significantly (all P＜0.05). ②Compared with normal control group, pulmonary artery of rabbits in LPS group had an increased contractile response to phenylephrine (PE) and a decreased relaxation response to acetylcholine (ACh) (both P＜0.01); Compared with LPS group, pulmonary artery of rabbits in LPS+NaHS group had a decreased contractile response to PE and an increased relaxation response to ACh (both P＜0.05). ③Under light microscope, the structure of vascular endothelial cells was continuous in the normal control group, the elastic fibers were intact in the subcutaneous layer, and the smooth muscle layer was arranged neatly. LPS can shed some of the pulmonary artery endothelial cells, break the subcutaneous elastic fibers, and disorder the smooth muscle layer structure. Compared with LPS group, the injury of pulmonary artery wall in LPS+NaHS group was ameliorated. The morphology of pulmonary artery wall was normal in NaHS group. It is showed that some endothelial cells of pulmonary artery were missing in LPS group by Scanning electron microscopy. The morphology of pulmonary artery endothelial cells in LPS+NaHS group was similar to that in the control group: slightly widened intercellular space was observed, and no cell exfoliation was observed. Conclusion: These results suggest that exogenous H₂S can protect pulmonary artery endothelial cells and regulate the reactivity changes of pulmonary artery during ES, which may be one of the mechanisms reducing PAH in ES rabbits.
Animals ; Endothelial Cells ; Hydrogen Sulfide/pharmacology* ; Hypertension, Pulmonary ; Lipopolysaccharides/adverse effects* ; Pulmonary Artery ; Rabbits ; Shock, Septic

The cardiac electrophysiological effects of hydrogen sulfide (H(2)S) on pacemaker cells in sinoatrial (SA) nodes of rabbits were examined using intracellular microelectrode technique. The results obtained were as follows: (1) The velocity of diastolic (phase 4) depolarization (VDD) and rate of pacemaker firing (RPF) in normal pacemaker cells in SA nodes were decreased by NaHS (H(2)S donor) (50, 100, 200 μmol/L) in a concentration-dependent manner; (2) ATP-sensitive K(+) (K(ATP)) channel blocker glybenclamide (Gli, 20 μmol/L) blocked the effect of NaHS (100 μmol/L) on pacemaker cells; (3) Pretreatment with CsCl (2 mmol/L), a blocker of pacemaker current (I(f)), did not affect the effect of NaHS (100 μmol/L) on SA node pacemaker cells; (4) DL-propargylglycine (PPG, 200 μmol/L), an inhibitor of cystathionine γ-lyase (CSE), did not affect the parameters of action potentials in pacemaker cells in SA nodes. All these results suggest that H(2)S exerts a negative chronotropic action on pacemaker cells in SA nodes of rabbits. These effects are likely due to an increase in potassium efflux through opening K(ATP) channels; I(f)is unlikely to play a major role in these effects. In our study, there was no evidence for the generation of endogenous H(2)S by CSE in SA node pacemaker cells.
Action Potentials ; Animals ; Glyburide ; pharmacology ; Hydrogen Sulfide ; pharmacology ; Microelectrodes ; Myocytes, Cardiac ; cytology ; drug effects ; Rabbits ; Sinoatrial Node ; cytology ; Sulfides ; pharmacology

Cell Line ; Epithelial-Mesenchymal Transition ; drug effects ; Humans ; Hydrogen Sulfide ; pharmacology ; Transforming Growth Factor beta1 ; pharmacology ; Wound Healing ; drug effects

OBJECTIVEPulmonary hypertension (PH) is a common complication of congenital heart defects with a left-to-right shunt characterized by high pulmonary blood flow. Pulmonary vascular structural remodeling (PVSR) is the pathological basis of PH. However, the pathophysiologic features and mechanisms responsible for PH and PVSR induced by increased pulmonary blood flow have not been fully understood. The present study was designed to explore the possible effect and mechanism of hydrogen sulfide (H(2)S) on the regulation of PVSR induced by high pulmonary flow in rats.

METHODSThirty-two male SD rats, weighing 120 - 140 g, were randomly divided into shunt group (n = 8), shunt + NaHS group (n = 8), control group (n = 8) and control + NaHS group (n = 8). Rats in shunt group and shunt + NaHS group were subjected to an abdominal aorta-inferior vena cava shunt to create an animal model of high pulmonary flow. Rats in the control and control + NaHS groups underwent the same experimental protocol as mentioned above except for the shunt procedure. Rats in the shunt + NaHS and control + NaHS groups were intraperitoneally injected with NaHS at 56 micromol/(kgxd), and rats in the shunt and control groups were injected with the same volume of physiological saline. After 11 weeks of experiment, rats were sacrificed and lung tissues were obtained. The percentage of muscularized artery (MA) was calculated. The changes in relative medial thickness (RMT) in small pulmonary arteries and median pulmonary arteries were examined. Proliferative cell nuclear antigen (PCNA), extracellular signal-regulated kinase (ERK1) and phosphorylation extracellular signal-regulated kinase (P-ERK1) protein expression were examined by Western blot, and at the same time, PCNA protein expression by pulmonary artery smooth muscle cells was observed by immunohistochemistry.

RESULTSAfter 11 weeks of shunt, compared with control group, the percentage of MA increased significantly (25.12 +/- 2.26 vs 14.42 +/- 3.41, P < 0.05), and RMT in small pulmonary arteries and median pulmonary arteries increased significantly in rats of shunt group (23.6 +/- 3.5 vs 12.6 +/- 2.1, 24.8 +/- 1.9 vs 13.5 +/- 2.2, P < 0.05 for all). PCNA protein expression in small and median pulmonary arteries increased significantly (0.49 +/- 0.04 vs 0.39 +/- 0.07, 0.46 +/- 0.08 vs 0.36 +/- 0.05, P < 0.01 for all), and the ratio of PERK/ERK1 protein expression of pulmonary arteries increased significantly (P < 0.01) in rats of shunt group compared with those of control group. After the administration of exogenous H(2)S donor, NaHS, for 11 weeks, in contrast to rats in shunt group, the percentage of MA decreased significantly (21.5 +/- 2.0 vs 25.1 +/- 2.3, P < 0.05), and RMT in small and median pulmonary arteries decreased significantly (20.2 +/- 2.8 vs 23.6 +/- 3.5, 20.8 +/- 3.1 vs 20.8 +/- 3.1, P < 0.05 for all) in rats of shunt + NaHS group. PCNA protein expression in small and median pulmonary artery smooth muscle cells decreased significantly (0.32 +/- 0.06 vs 0.49 +/- 0.04, 0.29 +/- 0.07 vs 0.46 +/- 0.08, P < 0.01 for all), and the ratio of PERK/ERK1 protein expression of pulmonary arteries decreased significantly (P < 0.01) in rats of shunt + NaHS group compared with that of shunt group.

CONCLUSIONH(2)S may play a regulatory role in pulmonary vascular structural remodeling induced by high pulmonary blood flow via mitogen-activated protein kinase (MAPK)/ERK signal transduction pathway.

Animals ; Hydrogen Sulfide ; pharmacology ; Hypertension, Pulmonary ; pathology ; physiopathology ; Lung ; pathology ; Male ; Pulmonary Artery ; drug effects ; physiopathology ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe the changes of pulmonary surfactant (PS) in rats with acute lung injury(ALI) induced by lipopolysaccharide (LPS) and to explore the effects of hydrogen sulfide (H2S) on PS.

METHODSFourty- eight male rats were randomly divided into six groups (n = 8). They were control group, LPS group, LPS+ NaHS low, middle, high dose groups and LPS+ PPG group. Saline was administrated in Control group. LPS was administrated in LPS group. In LPS + NaHS low, middle, high dose groups or LPS + PPG group, sodium hydrosulfide (NaHS) of different doses or DL-propargylglycine (PPG) were respectively administrated when the rats were administrated of LPS after 3 hours. All the rats were killed at 6 hours after administration of Saline or LPS. The morphological changes of alveolar epithelial type II cells (AEC-II) were respectively observed by transmission electron microscopes. The content of H2S in plasma and activity of cystathionine-gamma-lyase (CSE) in lung tissues were respectively detected. The contents of total protein (TP) and total phospholipids (TPL) in bronchoalveolar lavage fluid (BLAF) were respectively measured. The pulmonary surfactant protein A (SP-A), surfactant protein B (SP-B) and surfactant protein-C (SP-C) mRNA expressions in lung tissues were analysed.

RESULTS(1) Compared with control group, the content of H2S in plasma, activity of CSE, content of TPL, and SP-A, SP-B and SP-C mRNA expressions were respectively decreased in LPS group (P < 0.05 or P < 0.01). But the content of TP was increased in LPS group (P < 0.01); (2) Compared with LPS group, the content of H2S, activity of CSE and SP-A mRNA expression were significantly increased in LPS + NaHS low, middle and high dose groups (P < 0.05). The SP-B mRNA expression and content of TPL were significantly increased in LPS + NaHS Middle and High dose groups (P < 0.05). The content of TP was decreased in LPS + NaHS High dose group (P < 0.05). The SP-C mRNA expression was not altered in LPS+ NaHS low, middle and high dose groups (P > 0.05); (3) Compared with LPS group, the content of H2S, activity of CSE, content of TPL, and SP-A, SP-B and SP-C mRNA expressions were respectively decreased, but content of TP was increased in LPS + PPG group (P < 0.05).

CONCUSIONThe decrease of PS is the important physiopathologic process of ALI induced by LPS. Exogenously applied H2S could attenuate the process of ALI that possibly because H2S could adjust the compose and secretion of PS.

Acute Lung Injury ; chemically induced ; metabolism ; Animals ; Hydrogen Sulfide ; metabolism ; pharmacology ; Lipopolysaccharides ; Male ; Pulmonary Surfactants ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the influence of hydrogen sulfide on the intestinal biological barrier, by applying exogenous hydrogen sulfide and hydrogen sulfide synthase inhibitor for the treatment of rats with severe burn injury.

METHODSOne hundred and four SD rats were divided into sham injury (SI, n = 8), burn control (BC, n = 32), sodium hydrosulfide (SH, n = 32), and propargylglycine groups (PPG, n = 32) according to the random number table. Rats in group SI were sham injured without fluid resuscitation. Rats in the latter 3 groups were inflicted with 30% TBSA full-thickness scald (referred to as burn below) on the back and intraperitoneally injected with 40 mL/kg balanced salt solution immediately after injury. Rats in groups SH and PPG were respectively intraperitoneally injected with SH (56 µmol/kg) and PPG (45 mg/kg) within 1 hour post injury. From post injury day (PID) 2, SH (56 µmol/kg) and PPG (45 mg/kg) were respectively intraperitoneally injected once a day to rats in groups SH and PPG. Eight rats from groups BC, SH, and PPG were sacrificed on PID 2, 7, 14 and 21, and ceca samples were collected. Ceca samples were added to the appropriate culture medium after being homogenized and diluted, for the culture of Bifidobacterium, Lactobacillus, Enterococcus, Enterobacter, and Candida albicans. The content of bacteria was calculated after the bacteria number was counted. The same procedure was performed for rats in group SI. Data were processed with logarithmic function, one-way analysis of variance, analysis of variance of factorial design, and SNK-q test.

RESULTSOn each PID, the content of Bifidobacterium and Lactobacillus in the ceca of each group with burned rats was less than that of group SI (with q values from 4.12 to 20.74, P values below 0.05); while the content of Enterococcus, Enterobacter, and Candida albicans was more than that of group SI (with q values from 2.84 to 68.29, P values below 0.05). Compared with that of group BC, the content of Bifidobacterium and Lactobacillus in the ceca of rats in group SH were increased on each PID (with q values from 2.88 to 17.57, P values below 0.05). In group SH, the content of Bifidobacterium peaked as (6.54 ± 0.35) lg (CFU/g) on PID 7, the content of Lactobacillus peaked as (7.25 ± 0.71) lg (CFU/g) on PID 21. Compared with that of group BC, the content of Enterococcus, Enterobacter, and Candida albicans in the ceca of rats in group SH was reduced on each PID (with q values from 2.79 to 29.59, P values below 0.05). Compared with that of group BC, the content of Bifidobacterium and Lactobacillus in the ceca of rats in group PPG was decreased on each PID (with q values from 2.82 to 46.56, P values below 0.05); while the content of Enterococcus, Enterobacter, and Candida albicans was significantly increased on each PID (with q values from 2.93 to 41.42, P values below 0.05). In group PPG, the content of Enterococcus peaked as (9.41 ± 0.22) lg (CFU/g) on PID 21, the content of Enterobacter peaked as (9.96 ± 0.24) lg (CFU/g) on PID 14, and that of Candida albicans peaked as (3.94 ± 0.84) lg (CFU/g) on PID 14.

CONCLUSIONSExogenous hydrogen sulfide can subdue the growth of pathogenic bacteria while promote that of probiotics, thus helping maintain the integrity of intestinal biological barrier of rats with burn injury.

Animals ; Burns ; drug therapy ; pathology ; Hydrogen Sulfide ; pharmacology ; therapeutic use ; Intestines ; pathology ; Rats ; Rats, Sprague-Dawley ; Soft Tissue Injuries

OBJECTIVEEndogenous hydrogen sulfide (H2S), a novel gasotransmitter in cardiovascular regulation, plays an important protective role in the development and progression of atherosclerosis (AS). This study was designed to explore the effects of H2S donor on the production of adrenomedullin (ADM) and atrial natriuretic peptide (ANP) in AS rats.

METHODSMale Sprague-Dawley rats were randomly divided into control group (n=10), AS group (n=10), and AS+NaHS group (n=10). Rats in the AS and AS+NaHS groups were given 3-day intraperitoneal injections of vitamin D3 and 8-week high-fat diet to induce AS, and the rats in the AS+NaHS group were intraperitoneally injected with H2S donor NaHS. Oil red O staining was applied to detect changes in the areas of the atherosclerotic plaques in the aortic root and the coronary artery; sulfide-sensitive electrode method was used to measure the plasma concentration of H2S. ADM and ANP levels in plasma were determined by radioimmunoassay.

RESULTSCompared with the control group, marked atherosclerotic plaques were observed in the aortic root and the coronary artery in AS rats. Moreover, plasma H2S level decreased significantly, ADM level increased, and ANP level decreased significantly in AS rats (P<0.01). However, after the treatment with H2S donor NaHS for 8 weeks, the above changes in AS rats were reversed, demonstrated by significantly reduced areas of the atherosclerotic plaques in both the aortic root and the coronary artery, significantly increased plasma H2S level, significantly decreased plasma ADM level, and significantly increased plasma ANP level (P<0.01).

CONCLUSIONSH2S plays an important regulatory effect on vasoactive peptides ADM and ANP in AS rats.

Adrenomedullin ; biosynthesis ; Animals ; Atherosclerosis ; metabolism ; pathology ; Atrial Natriuretic Factor ; biosynthesis ; Hydrogen Sulfide ; pharmacology ; Male ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the effects of endogenous and exogenous hydrogen sulfide (H(2)S) on the K(ATP) current in isolated rat ventricular myocytes.

METHODSVentricular myocytes were isolated from rat heart by modified Langendorff perfusion with collagenase. K(ATP) current of single rat ventricular myocytes was recorded by whole-cell patch-clamp technique.

RESULTSThe density of K(ATP) current was significantly reduced by 200 micromol/L DL-propargylglycine (PPG, an irreversible inhibitor of the H(2)S) [(5.3258 +/- 0.7556) pA/pF vs. (3.7856 +/- 0.4312) pA/pF, P < 0.01] in a time-dependent way. The density of K(ATP) current could be significantly increased by NaHS (a H(2)S donor, 9.375, 18.75, 37.5, 75, 150 micromol/L) in a concentration-dependent manner [(6.6310 +/- 0.6092) pA/pF vs. (9.0949 +/- 1.0259) pA/pF at 150 micromol/L, P < 0.01].

CONCLUSIONBoth endogenous and exogenous H(2)S could open K(ATP) channels and enhance the K(ATP) current in rat ventricular myocytes.

Animals ; Cells, Cultured ; Hydrogen Sulfide ; pharmacology ; KATP Channels ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; Patch-Clamp Techniques ; Rats ; Rats, Wistar