Sulfur dioxide reduces lipopolysaccharide-induced acute lung injury in rats.

INTRODUCTION: Recent studies suggested that sulfur dioxide (SO2) can be produced endogenously by pulmonary vessels and attenuate acute lung injury (ALI) with vasorelaxant effects. This study was conducted to determine whether SO2 can inhibit lung inflammation and relax pulmonary arteries via inhibition of the mitogen-activated protein kinase (MAPK) pathway. MATERIAL AND METHODS: Forty-eight adult male Sprague Dawley rats (250~300 g) were randomly divided into six treatment groups: control (n = 8), control + SO2 (n = 8), control + L-aspartic acid-ß-hydroxamate (HDX) (n = 8), LPS (n = 8), LPS + SO2 (n = 8) and LPS + HDX (n = 8). RESULTS: Six hours after LPS treatment, rats exhibited elevated pulmonary artery hypertension (PAH), marked pulmonary structure injury with elevated pulmonary myeloperoxidase (MPO) activity and increased expression of intercellular adhesion molecule 1 (ICAM-1) and CD11b, along with decreased pulmonary SO2 production and reduced pulmonary aspartate aminotransferase (AAT) activity. Pretreatment with SO2 saline solution significantly reduced, while HDX (AAT inhibitor) aggravated, the pathogenesis of LPS-induced ALI. Moreover, SO2 saline solution significantly down-regulated expression of Raf-1, MEK-1 and phosphorylated ERK (p-ERK). It also prevented pulmonary hypertension in association with an up-regulated SO2/AAT pathway. However, HDX advanced pulmonary hypertension and inflammatory responses in the lung were associated with a down-regulated SO2/AAT pathway. CONCLUSIONS: Our results suggest that SO2 markedly relieved inflammatory responses, in association with Raf-1, MEK-1 and p-ERK during ALI induced by LPS. The down-regulation of the SO2/AAT pathway may be involved in the mechanism(s) of LPS-induced lung injury.

Sulfur dioxide attenuates LPS-induced acute lung injury via enhancing polymorphonuclear neutrophil apoptosis.

AIM: We speculated that the enhanced apoptosis of polymorphonuclear neutrophil (PMN) might be responsible for the inhibition of PMN infiltration in the lung. This study was designed to investigate the effects of sulfur dioxide (SO(2)) on PMN apoptosis in vivo and in vitro, which may mediate the protective action of SO(2) on pulmonary diseases. METHODS: Acute lung injury (ALI) was induced by intratracheally instillation of lipopolysaccharide (LPS, 100 µg/100 g, in 200 µL saline) in adult male SD rats. SO(2) solution (25 µmol/kg) was administered intraperitoneally 30 min before LPS treatment. The rats were killed 6 h after LPS treatment. Lung tissues were collected for histopathologic study and SO(2) concentration assay. Bronchoalveolar lavage fluid (BALF) was collected for the measurement of PMN apoptosis. For in vitro experiments, rat peripheral blood PMNs were cultured and treated with LPS (30 mg/L) and SO(2) (10, 20 and 30 µmol/L) for 6 h, and apoptosis-related protein expression was detected by Western blotting, and apoptosis rate was measured with flow cytometry. RESULTS: LPS treatment significantly reduced the SO(2) concentrations in the lung tissue and peripheral blood, as compared with the control group. Pretreatment with SO(2) prevented LPS-induced reduction of the SO(2) concentration in the lung tissue and peripheral blood. LPS treatment significantly reduced PMN apoptosis both in vivo and in vitro, which could be prevented by the pretreatment with SO(2). The protein levels of Caspase-3 and Bax was significantly increased, but Bcl-2 was decreased by the pretreatment with SO(2), as compared with LPS administration alone. CONCLUSION: SO(2) plays an important role as the modulator of PMN apoptosis during LPS-induced ALI, which might be one of the mechanisms underlying the protective action of SO(2) on pulmonary diseases.

[Hydrogen sulfide reduces lipopolysaccharide-induced acute lung injury and inhibits expression of phosphorylated p38 MAPK in rats].

To investigate the influence of hydrogen sulfide (H2S) on p38 MAPK signaling pathway during acute lung injury (ALI) caused by lipopolysaccharide (LPS), the rats were randomly divided into six groups: control group, LPS group, LPS + NaHS group, LPS + PPG (cystathionine-γ-lyase inhibitor) group, NaHS group and PPG group. The rats were sacrificed 6 h after injection and lung tissues were obtained. The structure of lung tissues and the number of polymorphonuclear leucocyte (PMN) was observed under optical microscope; the lung myeloperoxidase (MPO) activity, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were tested; intercellular adhesion molecule-1 (ICAM-1) protein expression changes were detected by immunohistochemical staining; phosphorylated p38 MAPK (p-p38 MAPK) protein expression was detected by Western blotting. The results showed that the lung injury in LPS group was observed, at the same time the MPO activity, the content of MDA, ICAM-1 and p-p38 MAPK protein expressions, the number of PMN were all higher than those in control group (all P < 0.05). Pre-injection of NaHS alleviated the changes induced by LPS, while pre-injection of PPG aggravated those alterations (all P < 0.05). ICAM-1 and p-p38 MAPK protein expressions in lung tissue were positively correlated (r = 0.923, P < 0.01). The results suggest that H2S may reduce LPS-induced ALI through inhibiting the conjugation of p38 MAPK and reducing the expression of ICAM-1.

[The interventional effects of saturated hydrogen saline on lung injury in rats with cecal ligation and puncture operation].

OBJECTIVE: To investigate the hypothesis that hydrogen could ameliorate cecal ligation and puncture (CLP)-induced lung injury of rats by inhibiting cystathionine-gamma-lyase/hydrogen sulfide (CSE/H2S) system. METHODS: A total number of 24 healthy male SD rats weighting 250～300 g were randomly divided into four groups (n=6 in each group): sham operation group(sham group), hydrogen-rich saline control group(H2 group), CLP group and hydrogen-rich saline treatment group(CLP+H2 group). The rats were treated with hydrogen-rich saline or saline 10 min before CLP or sham operation. At 8 h of sham or CLP operation, lung samples were obtained to detect the changes of the CSE/H2S system using biochemical and RT-PCR methods. In order to further confirm the role of H2S during hydrogen improve the lung injury of CLP rats, we also observed the effect of hydrogen-rich saline on the lung injury induced by H2S donor-sodium sodium hydrosulfide (NaHS). Thirty-two healthy male SD rats (250~300 g) were randomly divided into four groups (n=8 in each group): control group, H2S group, H2S+H2 group and H2 group. Saline(10 mg/kg) or NaHS(H2S donor, 56 µmol/kg) was injected intraperitoneally (10 mg/kg) respectively into rats in the control rats or H2S group. For rats in the H2S+H2 and H2 group, hydrogen-rich saline (10 mg/kg) was injected 10 min before saline or NaHS administration. Eight hours after the LPS saline or NaHS administration, lung coefficient, MDA content, and MPO activity were detected. The contents of TNF-α, IL-6 and IL-10 in lung tissue were measured, and the morphological changes of lung tissue were also observed. RESULTS: CSE/H2S system up-regulating were observed in animals exposed to CLP. Hydrogen-rich saline treatment significantly inhibited CSE/H2S system as indicated by significantly reduced H2S production in lung, along with a decreased CSE activity and CSE mRNA expression (all P＜0.05). Importantly, the results showed that lung injury and lung tissue inflammation were observed in animals exposed to NaHS. Hydrogen-rich saline treatment significantly attenuated lung injury as indicated by significantly improved histological changes in lung, significantly reduced index of quantitative assessment (IQA), MDA content and lung coefficient (all P＜0.05). MPO activity in lung tissue was significantly reduced along with decreased productions of TNF-α and IL-6, and an increased production of IL-10 in the presence of hydrogen (all P＜0.05), demonstrating antioxidant and anti-inflammatory effect of hydrogen in NaHS-induced ALI. CONCLUSION: These results indicate that hydrogen-rich saline peritoneal injection improves the lung injury induced by CLP operation. The therapeutic effects of hydrogen-rich saline may be related to suppressing the production of H2S.

[Diagnostic Values of IL-12 and IFN-γ for the Patients with Acute Leukemia].

OBJECTIVE: To explore the diagnostic values of interleukin-12 (IL-12) and interferon-γ (IFN-γ) for the patients with acute leukemia (AL). METHODS: A total of 76 cases of AL were enrolled in this study, and the 40 healthy persons were used as control group. The levels of IL-12 and IFN-γ were determined by enzyme linked immunosorbent assay (ELISA). The results were analyzed. RESULTS: The levels of IL-12 and IFN-γ in the untreated AL group, ALL and ANLL groups were lower significantly than those in the control group (P<0.05), there was no significant difference between untreated AL and ANLL groups (P>0.05). The levels of IL-12 and IFN-γ in CR patients of AL group after treatment obviously higher than that of patients before treatment (P<0.05), but there was no significant difference as campared with that in control. The levels of IL-12 and IFN-γ in NR patients of AL group after treatment were obviously lower than that in control group (P<0.05), but there was no significant difference in comparision with patients before treatment (P>0.05). The levels of IL-12 and IFN-γ of AL-CR and AL-NR patients before treatment were not significant difference before treatment (P>0.05). The levels of IL-12 and IFN-γ of AL-CR patients obviously higher than that in AL-NR patients (P<0.05). According to immure classification, the levels of IL-12 and IFN-γ of patients in untreated group were not significant difference. In regard to the clinical risk degree, the level of IL-12 of patients in untreated group was not obvious difference (P>0.05), but the level of IFN-γ of patients in untreated group was obvious different (P<0.05). The level of IL-12 of patients in untreated group positively correlated with level of IFN-γ (r=0.735, P<0.05), but the level of IL-12 did not significantly correlated with the level of IFN-γ (r=0.292, P>0.05). CONCLUSION: The serum levels of both IL-12 and IFN-γ are lower, but the changes of both serum levels may be helpful to diagnose and treatment of AL patients.

Risk assessment of heavy metals in air, water, vegetables, grains, and related soils irrigated with biogas slurry in Taihu Basin, China.

Metal contamination in farmlands irrigated with biogas slurry is of great concern because of its potential health risks to local inhabitants. Health risks that depend heavily on multi-pathway exposure to heavy metals (e.g., Pb, Cd, Cr, Zn, Cu, and As) in water, soil, air, and local food were studied through field sampling in Taihu Basin, China. Results show that Zn, Pb, and Cd in soils irrigated with biogas slurry exceed the soil quality standard values, and grown vegetables and grains contaminated with Pb and Cd exceed the permissible limits. Food ingestion plays an important role in the total average daily dose of metals, especially for Cu and Zn, which account for 94 and 91%, respectively. Non-carcinogenic risks posed to adults mainly result from Cu, Zn, Pb, Cd, and As through food ingestion and from Cr through soil ingestion. The highest non-carcinogenic risk was determined from food ingestion, followed by soil ingestion, air inhalation, air ingestion, and dermal contact with air. Carcinogenic risks to adults are 6.68 to 7.00 times higher than the safe level and can be attributed to Cr, As, and Cd pollution. The estimated risks mainly result from As and Cd through food ingestion and from Cr through soil ingestion. Both cancer and non-cancer risks through dermal contact can be ignored. Therefore, attention should be paid to health risks imposed by adults' multi-pathway exposure to heavy metals in vegetables, grains, and related soils irrigated with biogas slurry in Taihu Basin. Effective measures should be implemented to control heavy metal pollution and protect potentially exposed adults.

[Effect of exogenous hydrogen sulfide on polymorphonuclear neutrophil accumulation in acute lung injury rat induced by lipopolysaccharides and its mechanism].

OBJECTIVE: To study the effects of sodium hydrosulfide (NaHS), hydrogen sulfide (H2S) donor, on LPS-induced polymorphonuclear neutrophil (PMN) accumulation and its mechanism. METHODS: The animal model of acute lung injury (ALI) caused by intravenous injection of lipopolysaccharides (LPS). Adult male Spraguce-Dawley (SD) rats were randomly divided into four groups (n = 8 - 12 per group): Control group (0.5 ml/kg normal saline i.v.), LPS-treated group (1 mg/kg, i.v.), LPS plus NaHS (1 mg/kg i.v. and 28 micromol/kg i.p., respectively) and NaHS group (28 micromol/kg i.p.). Animals were sacrificed at 6 h after agent administration. Morphological changes of lung tissues were observed and polymorphonuclear neutrophil (PMN) number in alveolar septum was tested. The apoptosis of PMN in the bronchoalveolar lavage fluid (BALF) was examined with in situ TdT-mediated dUTP end labeling (TUNEL). Intercellular adhesion factor-1 (ICAM-1) and nuclear factor-kappaB (NF-kappaB) expressions in the lung tissue were analyzed by Western Blot. RESULTS: The results showed that bleeding, edema, PMN accumulation and other pathological signs in the lung tissue emerged after LPS injection. Compared to control rats, the LPS-treated rats had increased PMN number, decreased PMN apoptotic percentages, and increased expressions of ICAM-1 and NF-kappaB. Administration of NaHS into LPS-treated rats reduced the PMN number and expressions of ICAM-1 and NF-kappaB but increased PMN apoptotic percentages. In addition, NaHS alleviated the degree of ALI. There were no significant differences of the above indicators between NaHS-treated rats and control rats. CONCLUSION: NaHS can reduce the PMN accumulation in the lung, and its mechanism is related to down-regulation expression of ICAM-1 and promotion of PMN apoptosis induced by inhibition of NF-kappaB pathway.