Shock : molecular, cellular, and systemic pathobiological aspects and therapeutic approaches : the official journal the Shock Society, the European Shock Society, the Brazilian Shock Society, the International Federation of Shock Societies
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Hydrogen sulfide (H2S) is a novel gaseous mediator produced by cystathionine-beta-synthase and cystathionine-gamma-lyase in the cardiovascular system, including the heart. Using a rat model of regional myocardial ischemia/reperfusion, we investigated the effects of an H2S donor (sodium hydrogen sulfide [NaHS]) on the infarct size and apoptosis caused by ischemia (25 min) and reperfusion (2 h). Furthermore, we investigated the potential mechanism(s) of the cardioprotective effect(s) afforded by NaHS. ⋯ Furthermore, NaHS attenuated the increase in the I/R-induced (1) phosphorylation of p38 mitogen-activated protein kinase and Jun N-terminal kinase, (2) translocation from the cytosol to the nucleus of the p65 subunit of nuclear factor-kappaB, (3) intercellular adhesion molecule 1 expression, (4) polymorphonuclear leukocyte accumulation, (5) myeloperoxidase activity, (6) malondialdehyde levels, and (7) nitrotyrosine staining determined in the AAR obtained from rat hearts subjected to regional myocardial I/R. In conclusion, we demonstrate that the cardioprotective effect of NaHS is secondary to a combination of antiapoptotic and anti-inflammatory effects. The antiapoptotic effect of NaHS may be in part due to the opening of the putative mitochondrial adenosine triphosphate-sensitive potassium channels.
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Ventilator-induced lung injury is mediated, at least in part, by TNF-alpha. We determined the effect of a recombinant human soluble TNF receptor fusion protein (etanercept) on mechanical ventilation (MV)-induced changes in a murine ventilator-induced lung injury model. After pretreatment with etanercept or placebo, C57Bl/6 mice were anesthetized and randomized to MV with either low tidal volumes (VT, approximately 7.5 mL/kg) or high VT ( approximately 15 mL/kg) for 5 h. ⋯ Lung wet-to-dry ratios, histopathology scores, and local protein levels in BALF, however, were not influenced by etanercept treatment. The number of caspase 3-positive cells was significantly higher in etanercept-treated animals. Inhibition of TNF by etanercept attenuates, in part, MV-induced changes.