Effects of sulfur dioxide on the expressions of EGF, EGFR, and COX-2 in airway of asthmatic rats

Basiliximab Does Not Impair Airway Mucociliary Clearance of Rats

Previous studies have shown that immunosuppressive drugs impair the airway mucociliary clearance of rats. However, considering the high specificity of basiliximab (BSX) and the absence of studies reporting its side effects, our aim was to investigate whether BSX, associated or not with triple therapy, impairs the mucociliary system. Forty rats were divided into 4 groups: Control, BSX, Triple, and BSX + Triple. After 15 days of treatment, animals were euthanized and the ciliary beating frequency (CBF), mucociliary transport velocity (MCTV), neutral and acid mucin production, Muc5ac and Muc5b gene expression, inflammatory cell number, and interleukin (IL)-6 concentration were analyzed. CBF and MCTV were lower in Triple and BSX + Triple groups (p < 0.05). Neutral mucin percentage was higher in Triple group (p < 0.05), and acid mucin percentage was higher in Triple and BSX + Triple groups (p < 0.05). The Muc5ac and Muc5b gene expression was higher in Triple and BSX + Triple groups (p < 0.05). Animals from Triple and BSX + Triple groups presented fewer mononuclear cells (p < 0.05). The number of polymorphonuclear cells was higher in the Triple group (p < 0.05). In the analysis of inflammatory cells in the blood, there was a decrease in lymphocytes and an increase in neutrophils in the Triple and BSX + Triple groups (p < 0.05). The concentration of IL-6 significantly increased in the animals of the Triple and BSX + Triple groups (p < 0.05). BSX did not change the mucociliary apparatus of rats.

Sulfites in meat: Occurrence, activity, toxicity, regulation, and detection. A comprehensive review

Sulfites are a class of chemical compounds, SO₂ releasers, widely used as additives in food industry, due to their antimicrobial, color stabilizing, antibrowning, and antioxidant properties. As the results of these pleiotropic functions they can be added to a broad range of products including dried fruits and vegetables, seafood, juices, alcoholic and nonalcoholic beverage, and in few meat products. Sulfites ingestion has been correlated with several adverse and toxic reactions, such as hypersensitivity, allergic diseases, vitamin deficiency, and may lead to dysbiotic events of gut and oral microbiota. In many countries, these additives are closely regulated and in meat products the legislation restricts their usage. Several studies have been conducted to investigate the sulfites contents in meat and meat products, and many of them have revealed that some meat preparations represent one of the main sources of SO₂ exposure, especially in adults and young people. This review discusses properties, technological functions, regulation, and health implications of sulfites in meat-based foods, and lays a special emphasis on the chemical mechanisms involved in their interactions with organic and inorganic meat components.

Sulfur dioxide exposure reduces the quantity of CD19+ cells and causes nasal epithelial injury in rats

Background

Reactive airway dysfunction syndrome (RADS), also called irritant-induced asthma, is a type of occupational asthma that can occur within a very short period of latency. The study sought to investigate the influence of sulfur dioxide (SO₂) exposure on CD19+ cells and nasal epithelial injury.

Methods

We investigated the effects of SO₂ on CD19 expression and morphological changes of nasal epithelia in rats. In the study, 20 rats were randomly divided into the SO₂ exposure group that were exposed to 600 ppm SO₂, 2 h/day for consecutive 7 days, and the control group that were exposed to filtered air).

Results

Inhalation of high concentration of SO₂significantly reduced CD19 expression at both the mRNA transcript and protein levels, and reduced the percentages of CD19⁺ cells and CD19⁺/CD23⁺ cells in the nasal septum. However, inhalation of high concentration of SO₂ did not affect immunoglobulin (Ig) G, IgA and IgE levels in the serum and nasal septum. More importantly, SO₂ exposure also caused mild structural changes of the nasal septum.

Conclusion

Our results reveal that inhalation of a high concentration of SO₂ reduces CD19 expression and causes structural change of the nasal septum in rats.

The effect of exposure of SO2 in high concentrations on CD19+ cells in reactive airway dysfunction syndrome in rat

Reactive airway dysfunction syndrome (RADS) has a clinical manifestation similar to asthma, but some features are different between both the diseases. To probe the effect of CD19+ cells in RADS pathogenesis by inhalation of sulfur dioxide (SO2), rats were exposed to SO2 at 600 ppm for 2 h per day for 7 days and the CD19 expression in lung tissue was detected both at mRNA and protein levels by RT-PCR and western blot. The percentages of CD19+ and CD19+ CD23+ cells were measured by flow cytometry. IgG, IgA, and IgE in serum and bronchoalveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay (ELISA). Histological analysis was performed. The results showed that expression of CD19 in SO2 exposure group was lower than that in the control both at mRNA and protein levels ( P < 0.05). Flow cytometry analysis showed that the percentages of CD19+ and CD19+ CD23+ were significantly lower in the SO2 exposed group than that in the control ( P < 0.05). There was no difference between the control and SO2 exposed groups in both serum and BALF levels of IgG, IgA, and IgE. Pathological changes, such as chronic bronchitis, local alveolar hemorrhage, and lymphocytes infiltration were observed in SO2 exposed. RADS is a non-immunogenicity, chronic airway inflammatory disease caused by irritation of harmful factor and manifests as airway hyperresposiveness.

Fine Particulate Matter and Sulfur Dioxide Coexposures Induce Rat Lung Pathological Injury and Inflammatory Responses Via TLR4/p38/NF-κB Pathway

Fine particulate matter (PM_2.5) and sulfur dioxide (SO₂) are 2 common air pollutants, but their toxicological effects of coexposure are still not fully clear. In this study, SO₂ exposure (5.6 mg/m³) couldn't cause obvious inflammatory responses in rat lungs. The PM_2.5 exposure (1.5 mg/kg body weight) increased inflammatory cell counts in bronchoalveolar lavage fluid (BALF) and some inflammation damage. Importantly, SO₂ and PM_2.5 (1.5, 6.0, and 24.0 mg/kg) coexposure induced pathological and ultrastructural damage and raised inflammatory cells in BALF compared with the control. Also, they significantly elevated the levels of pro-inflammatory cytokines, adhesion molecule, and nitric oxide (NO) and promoted the gene expression of nuclear factor kappa B (NF-κB), phosphorylated p38 (p-p38), and Toll-like receptor 4 (TLR4) in rat lungs treated with higher dose of PM_2.5 (6.0 and 24.0 mg/kg) plus SO₂ relative to the control or SO₂ group, along with the decreased inhibitor of NF-κBα and increased inhibitor of NF-κB kinase β expressions. The changes in the inflammatory markers in the presence of PM_2.5 plus SO₂ were not significant compared with the PM_2.5 group. The results indicated that inflammatory injury and pathological and ultrastructural damage in rat lungs exposed to PM_2.5 plus SO₂ were involved in TLR4/p38/NF-κB pathway activation accompanied by oversecretion of pro-inflammatory cytokine, adhesion molecule, and NO. It provides more useful evidence to understand the possible toxicological mechanism that PM_2.5 and SO₂ copollution exacerbate lung disease.

Food safety risk assessment for estimating dietary intake of sulfites in the Taiwanese population

The purpose of this study was to assess the health risk associated with dietary intake of sulfites for Taiwanese general consumers by conducting a total diet study (TDS). We evaluated the exposure of Taiwanese to sulfites in the diet and its associated health risk. This study used a list of 128 food items representing 83% of the total daily diet. Among the 128 food items, 59 items may contain sulfites. Samples of the 59 food items were collected and subjected to chemical analysis to determine the sulfur dioxide concentration. Health risk was assessed by calculating the ratio of exposure level to the acceptable daily intake (ADI) level of the analyte. For high-intake consumers, the HI of sulfites was 19.7% ADI for males over the age of three years at the 95th percentile; whereas for females over the age of 66, the HI was 17.8% ADI. The HI for high-intake consumers was above 10% ADI. This suggests that regulatory actions must be continued and that consumers should be advised to be aware of processed foods with relatively high contamination to avoid excessive exposure.

Retinoid Homeostatic Gene Expression in Liver, Lung and Kidney: Ontogeny and Response to Vitamin A-Retinoic Acid (VARA) Supplementation from Birth to Adult Age

Vitamin A (VA, retinol) metabolism is homeostatically controlled, but little is known of its regulation in the postnatal period. Here, we determined the postnatal trajectory of VA storage and metabolism in major compartments of VA metabolism-plasma, liver, lung, and kidney from postnatal (P) day 1 to adulthood. We also investigated the response to supplementation with VARA, a combination of VA and 10% all-trans-retinoic acid that previously was shown to synergistically increase retinol uptake and storage in lung. Nursling pups of dams fed a VA-marginal diet received an oral dose of oil (placebo) or VARA on each of four neonatal days: P1, P4, P7, and P10; and again as adults. Tissues were collected 6 h after the final dosing on P1, P4, P10, and at adult age. Gene transcripts for Lrat and Rbp4 in liver and Raldh-1 and Raldh-3 in lung, did not differ in the neonatal period but were higher, P<0.05, in adults, while Cyp26B1, Stra6, megalin, and Raldh-2 in lung did not differ from perinatal to adult ages. VARA supplementation increased total retinol in plasma, liver and lung, with a dose-by-dose accumulation in neonatal liver and lung, while transcripts for Lrat in liver, megalin in kidney, Cyp26A1/B1 in liver and lung, respectively, and Stra6 in lung, were all increased, suggesting pathways of VA uptake, storage and RA oxidation were each augmented after VARA. VARA decreased hepatic expression of Rbp4, responsible for VA trafficking from liver to plasma, and, in lung, of Raldh-1 and Raldh-2, which function in RA production. Our results define retinoid homeostatic gene expression from neonatal and adult age and show that while supplementation with VARA acutely alters retinol content and retinoid homeostatic gene expression in neonatal and adult lung, liver and kidney, VARA supplementation of neonates increased adult-age VA content only in the liver.

Mechanisms of Heightened Airway Sensitivity and Responses to Inhaled SO2 in Asthmatics

Sulfur dioxide (SO2) is a problematic inhalable air pollutant in areas of widespread industrialization, not only in the United States but also in countries undergoing rapid industrialization, such as China, and it can be a potential trigger factor for asthma exacerbations. It is known that asthmatics are sensitive to the effects of SO2; however, the basis of this enhanced sensitivity remains incompletely understood. A PubMed search was performed over the course of 2014, encompassing the following terms: asthma, airway inflammation, sulfur dioxide, IL-10, mouse studies, and human studies. This search indicated that biomarkers of SO2 exposure, SO2 effects on airway epithelial cell function, and animal model data are useful in our understanding of the body's response to SO2, as are SO2-associated amplification of allergic inflammation, and potential promotion of neurogenic inflammation due to chemical irritant properties. While definitive answers are still being sought, these areas comprise important foci of consideration regarding asthmatic responses to inhaled SO2. Furthermore, IL-10 deficiency associated with asthma may be another important factor associated with an inability to resolve inflammation and mitigate oxidative stress resulting from SO2 inhalation, supporting the idea that asthmatics are predisposed to SO2 sensitivity, leading to asthma exacerbations and airway dysfunction.

Effect of sulfur dioxide on inflammatory and immune regulation in asthmatic rats

BACKGROUND

Exposure to sulfur dioxide (SO2) increases asthma risk. Inflammatory and immune responses are typical in asthma disease. The exact effect of SO2 on modulation of the inflammatory and immune responses in asthmatic rats remains unclear.

OBJECTIVES

Here we sought to investigate the molecular mechanisms underlying the NF-κB inflammatory pathway and the Th1/Th2 imbalance in asthmatic rats exposed to SO2.

METHODS

Male Wistar rats were challenged by ovalbumin (OVA) or SO2 alone or together, and then mRNA and protein levels of some inflammatory and immune genes were measured. NF-κB nuclear translocation was analyzed. Bronchoalveolar lavage (BAL), inflammatory cell counts and histopathologic examination were performed.

RESULTS

(1) OVA plus SO2 induced abnormal pathological changes and inflammatory responses in lung relative to exposure to OVA alone; (2) showing NF-κB nuclear translocation and activation through up-regulating IKKβ mRNA and protein expression and down-regulating IκBα expression in the presence of OVA or OVA plus SO2; (3) OVA plus SO2 significantly raised TNF-α and IL-6 levels in BALF compared with the OVA group; (4) SO2 markedly elevated IL-4 levels and decreased IFN-γ levels in BALF in the asthmatic rats, stimulating IgE generation which was closely related to inhibiting the expression of Foxp3, a specific marker of regulatory T cells.

CONCLUSIONS

SO2 affects the airway inflammatory and immune responses of the asthmatic rats and enhances the susceptibility to OVA by aggravating inflammatory responses in lungs, up-regulating pro-inflammatory cytokine expression, and causing the Th1/Th2 imbalance, which might contribute to the increased risk of asthma disease.

Chronic exposure to sulfur dioxide enhances airway hyperresponsiveness only in ovalbumin-sensitized rats

Sulfur dioxide (SO(2)) is a common air pollutant that triggers asthmatic symptoms, but its toxicological mechanisms are not fully understood. Specifically, it is unclear how airborne SO(2) affects airway hyperresponsiveness (AHR) - a hallmark feature of asthma. To this end, we investigated the effects of chronic exposure to SO(2) on AHR, airway inflammation, tissue remodeling, cell stiffness (G') and contractility of the airway smooth muscle cell (ASMC). Newborn Sprague-Dawley (SD) rats sensitized to ovalbumin (OVA) was used as the model to mimic asthmatic symptoms. The experimental results show that exposure to SO(2): (1) significantly increased Penh (an indicator of AHR) in the OVA-sensitized rats (p<0.01) but not in the normal rats (p>0.05), which correlated with the increase of airway smooth muscle mass; (2) increased IL-4 production in BALF of both the normal (p<0.05) and OVA-sensitized rats (p<0.001), but decreased IFN-γ in BALF of only the normal rats, and in serum only increased IL-4 production of the OVA-sensitized rats (p<0.001); (3) increased ASMC stiffness (G') and contractility only in the OVA-sensitized rats (p<0.001, p<0.05, respectively). Taken together, these results demonstrate that SO(2) may be a universal airway inflammatory factor, but more importantly, specific to exacerbating AHR in asthmatics only. These findings uncover a potential mechanism of SO(2)-induced health effects and may provide a basis for therapeutic targets.

Asthma drugs counter-regulate interleukin-8 release stimulated by sodium sulfite in an A549 cell line

BACKGROUND

Clinical manifestations suggest that air pollution may induce deterioration of respiratory health. Some air pollutants, including sulfite, may play a role in the exacerbation of asthma. Sulfites are formed at bronchial mucosa from inhaled sulfur dioxide. It has been previously reported that sodium sulfite (Na(2)SO(3)) has pro-inflammatory properties and enhances neutrophil adhesion to A549 cells. Interleukin-8 (IL-8) plays a critical role in attracting inflammatory cells and is an excellent marker of pulmonary cell activation. To date, there have not been any reports on the effect of asthma drugs on the suppression of IL-8 production induced by sulfite in A549 cells or the involvement of specific signal transduction pathways. Thus, our study assessed the effects of salmeterol, fluticasone, and montelukast on human epithelial lung cell inflammation as well as the inhibitors in different signal transduction pathways.

METHODS

A549 human lung epithelial cells were cultured under the following conditions: (1) treated with sodium sulfite (0, 100, 500, 1000, 2500 uM) for 16 hours; (2) cultured for 1 hour in the presence of SB203580, PD98059, SP600125, or wedeloactone, then co-incubated with sodium sulfite for another 16 hours; (3) cultured for 4 hours in the presence of salmeterol, fluticasone, or montelukast, then stimulated with sodium sulfite at a concentration of 1000 uM for 16 hours. We collected the supernatants from the above conditions and performed enzyme-linked immunosorbent assay (ELISA) to measure the IL-8 concentration.

RESULTS

IL-8 production increased after treatment with sodium sulfite at 1000 to 2500 uM (p <or= 0.001). SB203580, PD98059, and wedeloactone decreased IL-8 production stimulated by Na(2)SO(3) (p < 0.01). Salmeterol, fluticasone, and montelukast significantly suppressed IL-8 secretion from sodium sulfite-stimulated A549 cells (p < 0.01).

CONCLUSIONS

Sodium sulfite has pro-inflammatory properties in vitro and can induce potent chemotactic factor IL-8 production. Possible signal transduction pathways required for IL-8 gene expression following exposure to sulfite are the NF-kappa B, ERK, and p-38-dependent pathways. Salmeterol, fluticasone, and montelukast all have inhibitory effects on sodium sulfite-induced IL-8 production in A549 cells.