Hydrogen sulphide (H 2 S) is a naturally occurring gas, with potent vasodilator activity. In this report, we identify a role for H 2 S in carrageenan-induced hindpaw oedema in the rat. Intraplantar injection of carrageenan (150 ml, 2% (w v À1 )) resulted in an increase in hindpaw H 2 S synthesising enzyme activity and increased myeloperoxidase (MPO) activity. Pretreatment (i.p. 60 min before carrageenan) with DL-propargylglycine (PAG, 25-75 mg kg À1 ), an inhibitor of the H 2 S synthesising enzyme cystathionine-g-lyase (CSE), significantly reduced carrageenan-induced hindpaw oedema in a dose-dependent manner (e.g. increase in hindpaw weight at 3 h, saline: 0.1270.017 g; carrageenan, 1.3970.037 g; PAG, 50 mg kg

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Impaired lung function in severe acute pancreatitis is the primary cause of morbidity and mortality in this condition. Hydrogen sulfide (H(2)S) is a naturally occurring gas that has been shown to be a potent vasodilator. Diclofenac is a nonsteroidal anti-inflammatory drug and has been shown to have anti-inflammatory, analgesic, and antipyretic activity. ACS15 is an H(2)S-releasing derivative of diclofenac. Little is known about its effectiveness as an anti-inflammatory drug. In this report, we describe the effect of diclofenac and its H(2)S-releasing derivative on acute pancreatitis and associated lung injury in the mouse. Acute pancreatitis was induced in mice by hourly i.p. injections of cerulein. Diclofenac and ACS15 were administered either 1 hour before or 1 hour after starting cerulein injections, and the severity of acute pancreatitis and associated lung injury was assessed. The severity of acute pancreatitis was determined by hyperamylasemia, neutrophil sequestration in the pancreas (pancreatic myeloperoxidase activity), and pancreatic acinar cell injury/necrosis on histological examination of pancreas sections. The severity of acute pancreatitis-associated lung injury was assessed by neutrophil sequestration in the lungs (lung myeloperoxidase activity) and by histological examination of lung sections. ACS15, given prophylactically and therapeutically, significantly reduced lung inflammation without having any significant effect on pancreatic injury. These results suggest the usefulness of H(2)S-releasing nonsteroidal anti-inflammatory drugs as potential treatments for pancreatitis-associated lung injury.

Hydrogen sulfide (H2S), a novel gaseous messenger, is synthesized endogenously from L-cysteine by two pyridoxal-5′-phosphate-dependent enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). S-propargyl-cysteine (SPRC) is a slow H2S releasing drug that provides cysteine, a substrate of CSE. The present study was aimed to investigate the effects of SPRC in an in vivo model of acute pancreatitis (AP) in mice. AP was induced in mice by hourly caerulein injections (50 µg/kg) for 10 hours. Mice were treated with SPRC (10 mg/kg) or vehicle (distilled water). SPRC was administered either 12 h before or 3 h before the induction of pancreatitis. Mice were sacrificed 1 h after the last caerulein injection. Blood, pancreas and lung tissues were collected and processed to measure the plasma amylase, plasma H2S, myeloperoxidase (MPO) activities and cytokine levels in pancreas and lung. The results revealed that significant reduction of inflammation, both in pancreas and lung was associated with SPRC given 3 h prior to the induction of AP. Furthermore, the beneficial effects of SPRC were associated with reduction of pancreatic and pulmonary pro-inflammatory cytokines and increase of anti-inflammatory cytokine. SPRC administered 12 h before AP induction did not cause significant improvement in pancreatic and lung inflammation. Plasma H2S concentration showed significant difference in H2S levels between control, vehicle and SPRC (administered 3 h before AP) treatment groups. In conclusion, these data provide evidence for protective effects of SPRC in AP possibly by virtue of its slow release of endogenous H2S.

Hydrogen sulphide (H2S), a novel gasotransmitter, has been recognized to play an important role in inflammation. Cystathionine-γ-lyase (CSE) is a major H2S synthesizing enzyme in the cardiovascular system and DL-propargylglycine (PAG) is an irreversible inhibitor of CSE. Substance P (SP), a product of preprotachykinin-A (PPT-A) gene, is a well-known pro-inflammatory mediator which acts principally through the neurokinin-1 receptor (NK-1R). We have shown an association between H2S and SP in pulmonary inflammation as well as a pro-inflammatory role of H2S and SP in acute pancreatitis. The present study was aimed to investigate the interplay between pro-inflammatory effects of H2S and SP in a murine model of caerulein-induced acute pancreatitis. Acute pancreatitis was induced in mice by 10 hourly intraperitoneal injections of caerulein (50 (g/kg). PAG (100 mg/kg, i.p.) was administered either 1 hr before (prophylactic) or 1 hr after (therapeutic) the first caerulein injection. PAG, given prophylactically as well as therapeutically, significantly reduced plasma H2S levels and pancreatic H2S synthesizing activities as well as SP concentrations in plasma, pancreas and lung compared with caerulein-induced acute pancreatitis. Furthermore, prophylactic as well as therapeutic administration of PAG significantly reduced PPT-A mRNA expression and NK-1R mRNA expression in both pancreas and lung when compared with caerulein-induced acute pancreatitis. These results suggest that the pro-inflammatory effects of H2S may be mediated by SP-NK-1R pathway in acute pancreatitis.