Antiinflammatory and Antimicrobial Effects of Thiocyanate in a Cystic Fibrosis Mouse Model.

Thiocyanate (SCN) is used by the innate immune system, but less is known about its impact on inflammation and oxidative stress. Granulocytes oxidize SCN to evolve the bactericidal hypothiocyanous acid, which we previously demonstrated is metabolized by mammalian, but not bacterial, thioredoxin reductase (TrxR). There is also evidence that SCN is dysregulated in cystic fibrosis (CF), a disease marked by chronic infection and airway inflammation. To investigate antiinflammatory effects of SCN, we administered nebulized SCN or saline to ß epithelial sodium channel (ßENaC) mice, a phenotypic CF model. SCN significantly decreased airway neutrophil infiltrate and restored the redox ratio of glutathione in lung tissue and airway epithelial lining fluid to levels comparable to wild type. Furthermore, in Pseudomonas aeruginosa-infected ßENaC and wild-type mice, SCN decreased inflammation, proinflammatory cytokines, and bacterial load. SCN also decreased airway neutrophil chemokine keratinocyte chemoattractant (also known as C-X-C motif chemokine ligand 1) and glutathione sulfonamide, a biomarker of granulocyte oxidative activity, in uninfected ßENaC mice. Lung tissue TrxR activity and expression increased in inflamed lung tissue, providing in vivo evidence for the link between hypothiocyanous acid metabolism by TrxR and the promotion of selective biocide of pathogens. SCN treatment both suppressed inflammation and improved host defense, suggesting that nebulized SCN may have important therapeutic utility in diseases of both chronic airway inflammation and persistent bacterial infection, such as CF.

Protective effects of asiaticoside on septic lung injury in mice.

Asiaticoside (AS), a major triterpenoid saponin component isolated from Centella asiatica, has been described to exhibit antioxidant and anti-inflammatory activities. The present study aimed to determine the protective effects and the underlying mechanisms of AS on septic lung injury induced by cecal ligation and puncture (CLP). Mice were pretreated with the AS (45 mg/kg) or AS as well as GW9662 at 1h before CLP, the survival, lung injury, inflammatory mediators and signaling molecules, and Peroxisome proliferator-activated receptor-γ (PPAR-γ) were determined 24 h after CLP. The results showed that AS significantly decreased CLP-induced the mortality, lung pathological damage, the infiltration of mononuclear, polymorphonuclear (PMN) leucocytes and total proteins. Moreover, AS inhibited CLP-induced the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB), the expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein in lung tissues, and the production of serum tumor necrosis factor (TNF-α) and interleukin-6 (IL-6). Interestingly, the expression of PPAR-γ protein in lung tissue was up-regulated by AS. Furthermore, GW9662 (the inhibitor of PPAR-γ) significantly reversed these beneficial effects of AS in septic mice. These findings suggest that AS could effectively protect from septic lung injury induced by CLP and the underlying mechanisms might be related to up-regulation of PPAR-γ expression to some extent, which inhibits MAPKs and NF-κB pathway.