Pharmacodynamic evaluation of dihydroxyflavone derivate chrysin in a guinea pig model of allergic asthma.

OBJECTIVE: This experimental study evaluated the anti-asthmatic capacity of the dihydroxyflavone chrysin in the settings of ovalbumin (OVA)-induced allergic inflammation. METHODS: The parameters that were used to assess the anti-asthmatic activity of chrysin included the specific airway resistance to histamine, the sensitivity to a chemically induced cough and the activity of chrysin on the ciliary beat frequency (CBF) of the respiratory epithelium. The anti-inflammatory potential was confirmed by the measurement of cytokine concentrations Th2 (IL-4, IL-5 and IL-13), Th1 (Granulocyte-macrophage colony-stimulating factor [GM-CSF], INF-γ and IL-12), leucocyte count in the bronchoalveolar lavage fluid (BALF) and growth factor TBF-ß1 in lung homogenate. KEY FINDINGS: Chronic administration of chrysin (30 mg/kg/day for 21 days) to OVA-sensitised guinea pigs showed bronchodilatory activity comparable to that of long-acting ß 2 receptors agonist (LABA) salmeterol. Chrysin revealed antitussive efficiency but was not able to abolish the negative effect of OVA on CBF. Chrysin managed to ameliorate the progression of chronic airway inflammation by decreasing the count of eosinophils, lymphocytes and basophils, IL-5, L-13, GM-CSF, INF-γ in BALF, and TGF-ß1 in lung homogenate. CONCLUSIONS: The acquired results support the complex anti-asthmatic profile of chrysin. The flavone may represent an attractive compound for further studies concerning the prevention or treatment of asthma.

Effects of Inhalation of STIM-Orai Antagonist SKF 96365 on Ovalbumin-Induced Airway Remodeling in Guinea Pigs.

Airway remodeling (AR) consists of wall thickening and hyperreactivity. STIM (stromal interaction molecule) and Orai protein pathways mediate extracellular Ca2+ signals involved in AR. This study aims to define the effects on AR of the STIM-Orai antagonist SKF 96365 given by inhalation in three increasing doses in ovalbumin-induced AR. In the control group, the antiasthmatic budesonide and salbutamol were given in the same model. The airway structure was evaluated by histological and immunohistochemistry and reactivity by specific airway resistance, contraction strength of isolated airway smooth muscles, and mucociliary clearance expressed by ciliary beating frequency. The immuno-biochemical markers of chronic inflammation were evaluated by BioPlex and ELISA assays. The AR was mediated by inflammatory cytokines and growth factors. The findings show significant anti-remodeling effects of SKF 96365, which were associated with a decrease in airway hyperreactivity. The anti-remodeling effect of SKF 96365 was mediated via the suppression of IL-4, IL-5, and IL-13 synthesis, and IL-12-INF-γ-TGF-ß pathway. The budesonide-related AR suppression had to do with a decrease in proinflammatory cytokines and an increase in the anti-inflammatory IL-10, with negligible influence on growth factors synthesis and mucous glands activity.