Quantitative proteomics reveals tissue-specific toxic mechanisms for acute hydrogen sulfide-induced injury of diverse organs in pig.

Hydrogen sulfide (H2S) is a highly toxic gas in many environmental and occupational places. It can induce multiple organ injuries particularly in lung, trachea and liver, but the relevant mechanisms remain poorly understood. In this study, we used a TMT-based discovery proteomics to identify key proteins and correlated molecular pathways involved in the pathogenesis of acute H2S-induced toxicity in porcine lung, trachea and liver tissues. Pigs were subjected to acute inhalation exposure of up to 250 ppm of H2S for 5 h for the first time. Changes in hematology and biochemical indexes, serum inflammatory cytokines and histopathology demonstrated that acute H2S exposure induced organs inflammatory injury and dysfunction in the porcine lung, trachea and liver. The proteomic data showed 51, 99 and 84 proteins that were significantly altered in lung, trachea and liver, respectively. Gene ontology (GO) annotation, KEGG pathway and protein-protein interaction (PPI) network analysis revealed that acute H2S exposure affected the three organs via different mechanisms that were relatively similar between lung and trachea. Further analysis showed that acute H2S exposure caused inflammatory damages in the porcine lung and trachea through activating complement and coagulation cascades, and regulating the hyaluronan metabolic process. Whereas antigen presentation was found in the lung but oxidative stress and cell apoptosis was observed exclusively in the trachea. In the liver, an induced dysfunction was associated with protein processing in the endoplasmic reticulum and lipid metabolism. Further validation of some H2S responsive proteins using western blotting indicated that our proteomics data were highly reliable. Collectively, these findings provide insight into toxic molecular mechanisms that could potentially be targeted for therapeutic intervention for acute H2S intoxication.

Proteomics analysis of lung reveals inflammation and cell death induced by atmospheric H2S exposure in pig.

Hydrogen sulfide (H2S) is a popular toxic environmental gas and industrial pollutant, which can be harmful to multiple organ systems of both human and livestock, especially to the respiratory system. However, the injury mechanism of H2S exposure to lung remains poorly understood. In this study, pig lung was selected as a H2S exposure model for the first time. We first examined the histological damage and the mRNA expression of pro-inflammatory genes of lung in pigs exposed to H2S. Histopathology change and increased mRNA level of pro-inflammatory cytokines demonstrated that H2S exposure indeed induced inflammatory injury in the porcine lung. We then performed TMT-based quantitative proteomics analysis to probe the injury molecular mechanism. The proteomics results showed that 526 proteins have significant changes in abundance between control and H2S treated swine. Further validation analysis of some H2S responsive proteins using both Real-time quantitative PCR and western blotting demonstrated that proteomics data are reliable. KEGG pathway analysis revealed that these proteins were involved in antigen processing and presentation, complement and coagulation cascade, IL-17 signaling pathway, ferroptosis and necroptosis. Our data suggest that H2S exposure induced immune suppression, inflammatory response and cell death. These findings provide a new insight into the complexity mechanisms of H2S induced lung injury, and offer therapeutic potential as drug targets with a view towards curing the intoxication caused by H2S.

Effects of acute heat stress at different ambient temperature on hepatic redox status in broilers.

This study aimed to investigate the effects of different acute high ambient temperatures on redox status in liver of broilers. A total of 144 35-day-old Arbor Acres broilers were randomly divided into 4 groups with 6 replicates of 6 birds each and subsequently distributed in different environment chambers for acute heat stress. The temperature of 4 environment chambers were set to 26°C (control), 29°C, 32°C, 35°C for 6 h, respectively. Various indicators were tested to evaluate hepatic redox status. Then, the hallmarks of hepatocellular antioxidant and apoptosis were measured by qRT-PCR and Western Blot. The results showed that with the ambient temperature increase (i) the content of hydrogen peroxide (H2O2) and protein carbonyl (PC) in the liver of broilers increased significantly (P < 0.05), but the content of malondialdehyde (MDA) and 8-hydroxyguanosine (8-OHdG) was not affected; (ii) the activity of catalase (CAT) and glutathione reductase (GR) increased significantly (P < 0.05). Similarly, the superoxide dismutase (SOD) had an increasing tendency (P = 0.07), and the content of the reduced glutathione (GSH) was also significantly increased (P < 0.05) under high temperature; (iii) the heat shock protein (HSP70), nuclear factor erythroid-2-related factor 2 (Nrf2), and other antioxidant gene (HO-1, NQO1, GCLc, GST, SOD1, SOD2, CAT, Prx3) were upregulated in broilers liver. Moreover, the protein level of HSP70, Nrf2, and Prx3 were also upregulated; (iv) high temperature upregulated the antiapoptotic gene expression (BCL-2); however, the proapoptotic genes (BAK1, caspase-3, and caspase-9) did not change significantly; meanwhile, there was no significant changes in the protein level of caspase-3 and caspase-9. The results of this study indicated that 35-day-old Arbor Acres broilers have a certain tolerance to oxidative stress induced by high ambient temperature. Six hours of acute heat stress-activated Nrf2 signaling pathway. Meanwhile, the expression of related antioxidant genes and proteins is upregulated, consequently resulted in increased antioxidant enzymes activity and GSH. These effects enable the body to scavenge large amounts of reactive oxygen species produced by high temperature and prevent the occurrence of apoptosis.

Effects of flow and water chemistry on lead release rates from pipe scales.

Lead release from pipe scales was investigated under different water compositions, stagnation times, and flow regimes. Pipe scales containing PbO(2) and hydrocerussite (Pb(3)(OH)(2)(CO(3))(2)) were developed on lead pipes by conditioning the pipes with water containing free chlorine for eight months. Water chemistry and the composition of the pipe scales are two key factors affecting lead release from pipe scales. The water rarely reached equilibrium with pipe scales within one day, which makes solid-water contact time and corrosion product dissolution rates the controlling factors of lead concentrations for the conditions tested. Among five water compositions studied, a solution with orthophosphate had the lowest dissolved lead release rate and highest particulate lead release rate. Free chlorine also decreased the dissolved lead release rate at stagnant conditions. Water flow increased rates of release of both dissolved and particulate lead by accelerating the mass transfer of lead out of the porous pipe scales and by physically destabilizing pipe scales. Dissolved lead comprised the majority of the lead released at both stagnant and laminar flow conditions.

Formation of lead(IV) oxides from lead(II) compounds.

Lead(IV) oxide (PbO(2)) is a corrosion product that can develop on lead pipes used for drinking water supply, and its stability can control lead concentrations in tap water. A set of batch experiments were performed to determine the extent of PbO(2) formation as a function of time, pH, the presence of dissolved inorganic carbon (DIC), and free chlorine concentration. Experiments were conducted with four lead(II) compounds that are precursors of PbO(2) formation: dissolved lead(II) chloride, massicot (ß-PbO), cerussite (PbCO(3)), and hydrocerussite (Pb(3)(OH)(2)(CO(3))(2)). While PbO(2) formed in the presence and absence of DIC, the presence of DIC accelerated PbO(2) formation and affected the identity of the PbO(2) (scrutinyite vs plattnerite) product. For some conditions, intermediate solids formed that affected the identity of the PbO(2) produced. When no intermediate solids formed, hydrocerussite led to the formation of pure scrutinyite, and lead(II) chloride and massicot led to mixtures of scrutinyite and plattnerite. Based on the experimental results, a conceptual model of lead(IV) oxide formation pathways was proposed.

Impact of chlorine disinfectants on dissolution of the lead corrosion product PbO2.

Plattnerite (ß-PbO(2)) is a corrosion product that develops on lead pipes that have been in contact with free chlorine present as a residual disinfectant. The reductive dissolution of PbO(2) can cause elevated lead concentrations in tap water when the residual disinfectant is switched from free chlorine to monochloramine. The objectives of this study were to quantify plattnerite dissolution rates in the presence of chlorine disinfectants, gain insights into dissolution mechanisms, and measure plattnerite's equilibrium solubility in the presence of free chlorine. The effects of free chlorine and monochloramine on the dissolution rates of plattnerite were quantified in completely mixed continuous-flow reactors at relevant pH and dissolved inorganic carbon conditions. Plattnerite dissolution rates decreased in the following order: no disinfectant > monochloramine > chlorine, which was consistent with the trend in the redox potential. Compared with experiments without disinfectant, monochloramine inhibited plattnerite dissolution in continuous-flow experiments. Although free chlorine maintained steady-state lead concentrations below the action level of 15 µg/L in flow-through experiments, in batch experiments lead concentrations exceeded the action level for longer residence times and approached an equilibrium value that was several orders of magnitude higher than that predicted from available thermodynamic data.

Effects of pH and carbonate concentration on dissolution rates of the lead corrosion product PbO(2).

Lead(IV) oxide is a corrosion product that can develop on lead pipes and affect lead concentrations in drinking water. Continuously stirred flow-though reactors were used to quantify the dissolution rates of plattnerite (beta-PbO(2)) at different pH values and dissolved inorganic carbon (DIC) concentrations. Organic pH buffers were not used, because several were found to be reductants for PbO(2) that accelerated its dissolution. Most plattnerite dissolution rates were on the order of 10(-10) mol/min-m(2). The rate of dissolution increased with decreasing pH and with increasing DIC. The effect of DIC is consistent with a reductive dissolution mechanism that involves the reduction of Pb(IV) to Pb(II) at the plattnerite surface followed by the formation of soluble Pb(II)-carbonate complexes that accelerate Pb(II) release from the surface. Under the experimental conditions, dissolved lead concentrations were controlled by the dissolution rate of plattnerite and not by its equilibrium solubility. A dissolution rate model was developed and can be used to predict dissolution rates of plattnerite as a function of pH and DIC.

Effects of cetyltrimethylammonium chloride on uptake of pyrene by fish gills.

Laboratory experiments were carried out to study the effects of cationic surfactant cetyltrimethylammonium chloride (CTAC) on the uptake of pyrene by fish gills. The uptake (including adsorption) of pyrene by gills of the color carp (C. carpio var. color) exposed to 20-100 microg/L pyrene in the presence or absence of 0.2-1.0 mg/L CTAC were determined. The sorption of pyrene by mucus was preliminary studied using a four-step sequential extraction procedure. Fish gills were extracted with H2O, 0.01 M CaCl2, CH3OH and a mixture of 1:1 n-C6H14/CH2Cl2 in sequence. Results showed that pyrene mostly accumulated in mucus and on the surface of gills tissue; the cationic surfactant CTAC significantly enhanced these accumulation or adsorption on the fish gills (not in gills). CTAC could affect the bioavailability ofpyrene in aquatic systems.

Effects of sodium dodecylbenzenesulfonate on uptake of pyrene by fish gills.

Laboratory experiments were carried out to study the effects of anionic surfactant sodium dodecylbenzenesulfonate (SDBS) on the uptake of pyrene by fish gills. The uptake (including adsorption) of pyrene by gills of the color carp (C. carpio var. color) exposed to 20-100 microg/L pyrene in the presence or absence of 0.2-6.0 mg/L SDBS were determined. The sorption of pyrene by mucus was preliminary studied using a four-step sequential extraction procedure. Fish gills were extracted with H(2)O, 0.01 M CaCl(2), CH(3)OH and a mixture of 1:1 n-C(6)H(14)/CH(2)Cl(2) in sequence. Results showed that SDBS significantly affected these accumulation or adsorption on the fish gills (not in gills). SDBS could affect the bioavailability of pyrene in aquatic systems.

A method for determining pyrene in mucus using synchronous fluorimetry with multiple standard additions.

A new method was proposed to determine pyrene in mucus, which combined the synchronous fluorimetry with the multiple standard addition method (SFMSA). The method was used to determine pyrene in mucus directly without pretreatment. The method detection limit (MDL) for pyrene in mucus was measured as 0.47 ng/ml with a relative standard deviation of 12.7% (n = 7). The standard addition graph was linear in the range 0.05-50.00 ng/ml (r(2) = 0.9989). SFMSA was validated using a GC/MS method as a reference method, and nice agreement was found. The pyrene in mucus can be directly monitored by SFMSA without solvent extraction of samples. This indicates that SFMSA is more timesaving, less laborious and cheaper than the GC/MS method with solvent extraction. SFMSA has lower MDL and higher average recovery than the GC/MS method.