BackgroundAsthma is an inflammatory condition characterized by airway hyperresponsiveness and chronic inflammation. The resolution of inflammation is an essential process to treat this condition. In this study we investigated the effect of Allium cepa L. extract (AcE) and quercetin (Qt) on cytokine and on smooth muscle contraction in vitro and its therapeutic potential in a murine model of asthma.MethodsAcE was obtained by maceration of Allium cepa L. and it was standardized in terms of quercetin concentration using high performance liquid chromatography (HPLC). In vitro, using AcE 10, 100 or 1000 μg/ml or Qt 3.5, 7.5, 15 μg/ml, we measured the concentration of cytokines in spleen cell culture supernatants, and the ability to relax tracheal smooth muscle from A/J mice. In vivo, Blomia tropicalis (BT)-sensitized A/J mice were treated with AcE 100, 1000 mg/kg or 30 mg/kg Qt. We measured cell influx in bronchoalveolar lavage (BAL), eosinophil peroxidase (EPO) in lungs, serum levels of Bt-specific IgE, cytokines levels in BAL, and lung histology.ResultsWe observed a reduction in the production of inflammatory cytokines, a relaxation of tracheal rings, and a reduction in total number of cells in BAL and EPO in lungs by treatment with AcE or Qt.ConclusionAcE and Qt have potential as antiasthmatic drugs, as they possess both immunomodulatory and bronchodilatory properties.

BackgroundThe dust mite Blomia tropicalis is an important source of aeroallergens in tropical areas. Although a mouse model for B. tropicalis extract (BtE)-induced asthma has been described, no study comparing different mouse strains in this asthma model has been reported. The relevance and reproducibility of experimental animal models of allergy depends on the genetic background of the animal, the molecular composition of the allergen and the experimental protocol.ObjectivesThis work had two objectives. The first was to study the anti-B. tropicalis allergic responses in different mouse strains using a short-term model of respiratory allergy to BtE. This study included the comparison of the allergic responses elicited by BtE with those elicited by ovalbumin in mice of the strain that responded better to BtE sensitization. The second objective was to investigate whether the best responder mouse strain could be used in an experimental model of allergy employing relatively low BtE doses.MethodsGroups of mice of four different syngeneic strains were sensitized subcutaneously with 100 μg of BtE on days 0 and 7 and challenged four times intranasally, at days 8, 10, 12, and 14, with 10 μg of BtE. A/J mice, that were the best responders to BtE sensitization, were used to compare the B. tropicalis-specific asthma experimental model with the conventional experimental model of ovalbumin (OVA)-specific asthma. A/J mice were also sensitized with a lower dose of BtE.ResultsMice of all strains had lung inflammatory-cell infiltration and increased levels of anti-BtE IgE antibodies, but these responses were significantly more intense in A/J mice than in CBA/J, BALB/c or C57BL/6J mice. Immunization of A/J mice with BtE induced a more intense airway eosinophil influx, higher levels of total IgE, similar airway hyperreactivity to methacholine but less intense mucous production, and lower levels of specific IgE, IgG1 and IgG2 antibodies than sensitization with OVA. Finally, immunization with a relatively low BtE dose (10 μg per subcutaneous injection per mouse) was able to sensitize A/J mice, which were the best responders to high-dose BtE immunization, for the development of allergy-associated immune and lung inflammatory responses.ConclusionsThe described short-term model of BtE-induced allergic lung disease is reproducible in different syngeneic mouse strains, and mice of the A/J strain was the most responsive to it. In addition, it was shown that OVA and BtE induce quantitatively different immune responses in A/J mice and that the experimental model can be set up with low amounts of BtE.

Allergic asthma has emerged as an important public health problem of urban populations in developed countries. Very often herbal medicine is used to treat this widespread disease, due to the lack of efficacy and the important side effects related to the classical drugs in use. Along this line, Ocimum gratissimum (Og) is a plant widely used in Brazilian folk medicine to treat inflammatory disorders, such as asthma. In the present study we evaluated the immunomodulatory effects of Og and rosmarinic acid (RA, a polyphenolic compound) in a murine model of respiratory allergy induced by the Blomia tropicalis (Bt) mite. The respiratory allergy was induced in A/J mice by administration of Bt extract and the treatment was done using 25, 50 or 100mg/kg of an Og methanolic extract or using 2, 20 or 200mg/kg of RA. We then evaluated the changes induced by these drugs on immunological parameters related to the allergic process, which are up-regulated in this allergic model. The treatment of animals with 100mg/Kg Og and 200mg/Kg RA led to a significant reduction in the numbers of leukocytes/eosinophils in bronchoalveolar lavage (BAL); eosinophil peroxidase activity in BAL; presence of mucus in respiratory tract, histopathological changes in the lung, and IL-4 in BAL. These results suggest that the methanolic extract of Og and the polyphenol RA have therapeutic potential in this murine model of respiratory allergy to a clinically relevant human sensitizer allergen.

Asthma is one of the most prevalent chronic diseases worldwide. Medicinal plants are historically used in its treatment. The plant Cissampelos sympodialis, known in Northeastern Brazil as "Jarrinha" or "Milona", is used to treat some inflammatory conditions, including asthma. The objective of this study was to evaluate the potential of Cissampelos sympodialis EICHL. extract (CsE) and its isolated alkaloids, especially warifteine (Wa) on a Blomia tropicalis extract (BtE)-induced experimental model of allergy. The respiratory allergy was induced in AJ mice by the administration of BtE. Mice were orally treated with the 400 mg/kg of CsE or 8 mg/kg of total alkaloids fraction (TAF) or 4 mg/kg of Wa and the following parameters were analyzed: (a) total cell numbers in bronchoalveolar fluid (BAF); (b) differential cell numbers in BAF; (c) eosinophil peroxidase (EPO) activity in BAF; (d) IgE serum levels by passive cutaneous anaphylaxis; (e) IL-5, IL-13, IL-10, and IFN-γ levels in BAF; (f) histopathological alterations in the lung. The treatment of the animals with CsE, Wa or TAF led to a reduction in the numbers of total cells and eosinophils in BAF. The same reduction was observed in EPO levels in the BAF. The levels of IL-5 and IL-13 were also reduced in animals treated with Cissampelos sympodialis, while IL-10 levels were significantly increased in the BAF of CsE-treated animals. The treatment also decreased the density of inflammatory cells in the lung by histopathological examination demonstrating the potential of this medicinal plant as new agent for asthma treatment.

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