ABSTRACT
Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common clinical syndrome of diffuse lung inflammation with high mortality rates and limited therapeutic methods. Diosmetin, an active component from Chinese herbs, has long been noticed because of its antioxidant and anti-inflammatory activities. The aim of this study was to evaluate the effects of diosmetin on LPS-induced ALI model and unveil the possible mechanisms. Our results revealed that pretreatment with diosmetin effectively alleviated lung histopathological changes, which were further evaluated by lung injury scores. Diosmetin also decreased lung wet/dry ratios, as well as total protein levels, inflammatory cell infiltration and proinflammatory cytokine (eg. TNF-α, IL-1β and IL-6) overproduction in bronchoalveolar lavage fluid (BALF). Additionally, increased MPO, MDA and ROS levels induced by LPS were also markly suppressed by diosmetin. Furthermore, diosmetin significantly increased the expression of Nrf2 along with its target gene HO-1 and blocked the activation of NLRP3 inflammasome in the lung tissues, which might be central to the protective effects of diosmetin. Further supporting these results, in vitro experiments also showed that diosmetin activated Nrf2 and HO-1, as well as inhibited the NLRP3 inflammasome in both RAW264.7 and A549 cells. The present study highlights the protective effects of diosmetin on LPS-induced ALI via activation of Nrf2 and inhibition of NLRP3 inflammasome, bringing up the hope of its application as a therapeutic drug towards LPS-induced ALI.
Subject(s)
Humans , Acute Lung Injury , Asian People , Bronchoalveolar Lavage Fluid , Hope , In Vitro Techniques , Inflammasomes , Lung , Lung Injury , Mortality , PneumoniaABSTRACT
Geniposide, a main iridoid glucoside component of gardenia fruit, has been shown to possess anti-inflammatory activity. However, its potential use for acute lung injury (ALI) has not yet been studied. The aim of this study was to evaluate the anti-inflammatory properties of geniposide using a mouse ALI model. ALI was induced by intranasal injection of lipopolysaccharide (LPS). Pretreatment of mice with geniposide (20, 40, or 80 mg/kg) resulted in a marked reduction in inflammatory cells and total protein concentration in the bronchoalveolar lavage fluid (BALF) of mice. Levels of inflammatory mediators, including tumour necrosis factor- α (TNF- α), interleukin-6 (IL-6), and interleukin-10 (IL-10), were significantly altered after treatment with geniposide. Histological studies using hematoxylin and eosin (H&E) staining demonstrate that geniposide substantially inhibited LPS-induced alveolar wall changes, alveolar haemorrhage, and neutrophil infiltration in lung tissue, with evidence of reduced myeloperoxidase (MPO) activity. In addition, we investigated potential signal transduction mechanisms that could be implicated in geniposide activity. Our results suggest that geniposide may provide protective effects against LPS-induced ALI by mitigating inflammatory responses and that the compound's mechanism of action may involve blocking nuclear factor-kappaB (NF- κB) and mitogen-activated protein kinases (MAPK) signalling pathway activation.
Subject(s)
Acute Lung Injury/prevention & control , Anti-Inflammatory Agents/therapeutic use , Gardenia/chemistry , Iridoids/therapeutic use , Signal Transduction/drug effects , Acute Lung Injury/chemically induced , Animals , Anti-Inflammatory Agents/pharmacology , Cytokines/analysis , Disease Models, Animal , Dose-Response Relationship, Drug , Fruit/chemistry , Iridoid Glucosides/pharmacology , Iridoid Glucosides/therapeutic use , Iridoids/pharmacology , Lipopolysaccharides/toxicity , Lung/drug effects , Lung/metabolism , Lung/pathology , Male , Mice , Mice, Inbred BALB C , Mitogen-Activated Protein Kinase Kinases/drug effects , Mitogen-Activated Protein Kinase Kinases/metabolism , NF-kappa B/drug effects , NF-kappa B/metabolism , Peroxidase/metabolism , Plants, Medicinal/chemistry , Random AllocationABSTRACT
Florfenicol has been shown to possess anti-inflammatory activity. However, its possible use for asthma has not yet been studied. First we investigated the anti-inflammatory properties of florfenicol using mice asthma model. BALB/c mice were immunized and challenged by ovalbumin. Treatment with florfenicol caused a marked reduction in inflammatory cells and three Th2 type cytokines in the bronchoalveolar lavage fluids of mice. The levels of ovalbumin-specific IgE and airway hyperresponsiveness were significantly altered after treatment with florfenicol. Histological studies using H&E and AB-PAS staining demonstrate that florfenicol substantially inhibited ovalbumin-induced inflammatory cells infiltration in lung tissue and goblet cell hyperplasia in the airway. These results were similar to those obtained with dexamethasone treatment. We then investigated which signal transduction mechanisms could be implicated in florfenicol activity. Our results suggested that the protective effect of florfenicol was mediated by the inhibition of the p38 MAPK-mediated phosphorylation of GATA 3.
