Abstract
BackgroundDianthus superbus has long been used as a herbal medicine in Asia and as an anti-inflammatory agent. In this study, we evaluated the anti-inflammatory effects of Dianthus superbus fructus ethanolic extract (DSE) on Th2-type cytokines, eosinophil infiltration, and other factors in an ovalbumin (OVA)-induced murine asthma model. To study the possible mechanism of the anti-inflammatory effect of DSE, we also evaluated the expression of inducible nitric oxide synthase (iNOS) in the respiratory tract.MethodsMice were sensitized on days 0 and 14 by intraperitoneal injection of OVA. On days 21, 22 and 23 after initial sensitization, mice received an airway challenge with OVA for 1 h using an ultrasonic nebulizer. DSE was applied 1 h prior to OVA challenge. Mice were administered DSE orally at doses of 100 mg/kg or 200 mg/kg once daily from day 18 to 23. Bronchoalveolar lavage fluid (BALF) was collected 48 h after the final OVA challenge. Levels of interleukin (IL)-4, IL-13 and eotaxin in BALF were measured using enzyme-linked immunosorbent assays (ELISAs). Lung tissue sections were stained with hematoxylin and eosin for assessment of cell infiltration and mucus production with periodic acid shift staining, in conjunction with ELISA and western blot analyses for iNOS expression.ResultsDSE significantly reduced the levels of IL-4, IL-13, eotaxin, and immunoglobulin (Ig) E, number of inflammatory cells in BALF, and inflammatory cell infiltration and mucus production in the respiratory tract. DSE also attenuated the overexpression of iNOS protein induced by OVA challenge.ConclusionOur results suggest that DSE effectively protects against allergic airway inflammation by downregulating of iNOS expression and that DSE has potential as a therapeutic agent for allergic asthma.
Highlights
Dianthus superbus has long been used as a herbal medicine in Asia and as an anti-inflammatory agent
Reduction in inducible nitric oxide synthase (iNOS) expression in lung tissue from OVA-induced mice To identify the possible protective mechanism underlying the activity of Dianthus superbus fructus ethanolic extract (DSE) in airway inflammation, we investigated the expression of iNOS protein in relation to inflammation in lungs of OVA-induced mice
DSE-treated mice had fewer inflammatory cells, in particular eosinophils, in Bronchoalveolar lavage fluid (BALF) and lung tissue, and lower levels of IL-4, IL-13, and eotaxin in BALF compared with OVA-induced mice
Summary
Dianthus superbus has long been used as a herbal medicine in Asia and as an anti-inflammatory agent. We evaluated the anti-inflammatory effects of Dianthus superbus fructus ethanolic extract (DSE) on Th2-type cytokines, eosinophil infiltration, and other factors in an ovalbumin (OVA)-induced murine asthma model. Allergic asthma is caused mainly by allergens such as house dust, inhalants, foods, drugs, and animal dander and its symptoms include wheezing, coughing, tightness of the chest, and breathlessness [2,3,4]. These symptoms results from bronchoconstriction interleukin (IL)-4, IL-5, and IL-13, which exacerbate the allergic response by increasing inflammatory cell infiltration into the airway and immunoglobulin (Ig)E secretion, and by stimulating mucus hypersecretion [7,8]. Recent studies have shown that reducing iNOS expression attenuates the asthmatic response in the respiratory tract in various asthma models [10,12,13]
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