ovalbumin and ramatroban

Eosinophilic esophagitis is characterized by eosinophil-predominant inflammation in the esophagus. How eosinophils migrate and infiltrate into the esophagus, however, is less clear. Our previous study demonstrated that mast cell activation led to eosinophil infiltration in the esophagus. Prostaglandin D2 (PGD2) is an important mediator released from activated mast cells. The present study aims to determine whether PGD2 induces eosinophil infiltration into the esophagus via a d-type prostanoid receptor 2 (DP2) receptor-dependent mechanism. Using an in vivo guinea pig model, PGD2, d-type prostanoid receptor 1 (DP1) agonist, or DP2 agonist were injected into the esophagus. Esophageal tissues were removed 2 hours after injections and proceeded to either hematoxylin-eosin (HE) staining or immunofluorescent staining of eosinophil major basic protein (MBP) to compare each treatment-induced eosinophil infiltration in the esophagus. In a separate study, ovalbumin (OVA)-sensitized guinea pigs were pretreated with either DP2 or DP1 antagonists, followed by inhalation of OVA to induce mast cell activation. Esophageal tissues were then processed for immunofluorescent staining of MBP. PGD2 injection in the esophagus led to an increase of eosinophil infiltration in esophageal epithelium at the injection site as revealed by HE staining. Increased infiltration of eosinophils was further confirmed by the increased presence of MBP-labeled immunopositive (MBP-LI) cells in esophageal epithelium. Injection with DP2 agonist 15(R)-PGD2, but not DP1 agonist BW 245C, mimicked the PGD2-induced response. In OVA-sensitized animals, antigen inhalation increased MBP-LI cells in esophageal epithelium. Pretreatment with DP2 antagonist BAY-u3405, but not DP1 antagonist BW 868C, inhibited the antigen inhalation-induced increase of MBP-LI cells in esophageal epithelium. These data support the hypothesis that PGD2 induces eosinophil trafficking into the esophageal epithelium via a DP2-mediated pathway, suggesting a role of DP2 antagonist in the prevention of eosinophilic esophagitis.

Topics: Animals; Carbazoles; Cell Movement; Eosinophil Major Basic Protein; Eosinophilic Esophagitis; Eosinophils; Epithelium; Esophagus; Guinea Pigs; Hydantoins; Male; Mast Cells; Ovalbumin; Prostaglandin Antagonists; Prostaglandin D2; Receptors, Immunologic; Receptors, Prostaglandin; Sulfonamides

Chemoattractant receptor homologous molecule expressed on T helper type 2 cells (CRTH2) is a PGD2 receptor found on eosinophils, basophils, and Th2 type T cells which exhibits chemotaxis and functions in activation cascades. However, while a number of CRTH2 antagonists, including ramatroban, are known to exert activity in certain animal models, activity in a guinea pig model of EA-induced airway hyperresponsiveness has not been demonstrated. The newly developed CRTH2 antagonist ASP5642 has shown antagonistic activity against human and guinea pig CRTH2 in previous studies and has also been found effective in treating guinea pig models of airway inflammation and airway hyperresponsiveness. While previous studies have used animals such as rats and mice to evaluate CRTH2 antagonist effects, ours is the first attempt to evaluate CRTH2 function in a guinea pig asthma model, which may prove useful in evaluating the compound's effects in humans, given the comparable airway function between the two species taken together, these data from the present study strongly suggest the utility of ASP5642 in investigating the role of CRTH2 in inflammatory responses and as a drug treatment for human asthma.

Topics: Animals; Anti-Asthmatic Agents; Anti-Inflammatory Agents; Antigens; Benzhydryl Compounds; Bronchial Hyperreactivity; Bronchoalveolar Lavage Fluid; Carbazoles; Cell Count; Eosinophilia; Guinea Pigs; HEK293 Cells; Humans; K562 Cells; Male; Ovalbumin; Pneumonia; Prostaglandin D2; Pyridazines; Receptors, Immunologic; Receptors, Prostaglandin; Sulfonamides

To investigate the effect of prostaglandin D2 receptor antagonists on the airway inflammation in rats with asthma.. Forty male SD rats were randomly divided into four groups: Group A (normal control), Group B (asthma group), Group C (CRTH2 antagonist BAYu3405 treatment group), Group D (DP1 antagonist BWA868C treatment group). Asthma was induced by ovalbumin (OVA) challenge. The rats in each group were sacrificed 24 h after the last challenge of OVA.DP1/CRTH2 receptors on eosinophils (EOS) were measured by radiological binding assay (RBA). The left lungs were used for histological examinations and bronchoalveolar lavage fluid (BALF) was collected from the right lungs. The total cell numbers, EOS absolute count and differential cell counts in BALF were performed. Serum concentrations of IL-4, 5 and IFN-gamma were measured by ELISA.. Rats in BAYu3405 treatment group showed profoundly decreased infiltrates of EOS and lymphocytes in the wall of bronchus when compared with those of asthma group and BWA868C treatment group. Serum concentrations of IFN-gamma in rats of BAYu3405 treatment group increased, but IL-4 and IL-5 decreased significantly when compared with those in rats of asthma group and BWA868C treatment group (P<0.01), and BALF EOS count was decreased significantly (P<0.01). Peripheral blood EOS count was higher than that in rats of normal control group, but was not significantly different from that in rats of asthma group and BWA868C treatment group. The combining capacity of CRTH2 and DP total combining capacity on EOS in asthma group, BAYu3405 treatment group and BWA868C treatment group were significantly higher than those in Group A (P<0.01). There was no significant difference in DP1 among all the groups (P>0.05).. CRTH2, but not DP1 antagonist can effectively ameliorate airway inflammation in rats with asthma.

Topics: Animals; Asthma; Bronchi; Carbazoles; Inflammation; Male; Ovalbumin; Prostaglandin D2; Random Allocation; Rats; Rats, Sprague-Dawley; Receptors, Immunologic; Receptors, Prostaglandin; Sulfonamides

Interleukin-16 (IL-16) is a cytokine that induces selective migration of CD4+ cells and participates in inflammatory diseases including allergic rhinitis. Histamine and prostaglandin D(2) are important chemical mediators of allergic inflammation, and antiallergic drugs are commonly used for the treatment of allergic rhinitis. It remains unknown whether treatment with the drugs affects IL-16.. We evaluated the variability of IL-16 and the effects of the antiallergic drugs fexofenadine (40 mg/kg/day) and ramatroban (30 mg/kg/day) on IL-16 in an OVA-sensitized BALB/c murine experimental allergic rhinitis model.. We measured the expression level of IL-16 protein in the mouse nasal septal mucosa by immunohistochemistry, and the serum level of IL-16 by ELISA. Several other parameters associated with allergic rhinitis (nasal symptoms, OVA-specific IgE, eosinophil and T cell infiltration) were also measured.. Local and systemic expressions of IL-16 were significantly increased in OVA-sensitized mice when compared to the nonsensitized group. Fexofenadine and ramatroban significantly inhibited the following OVA-induced allergic features when compared to the nontreated sensitized group: sneezing, nasal rubbing, eosinophil infiltration, IL-16 expressions in nasal tissue, and serum IL-16 level. Serum OVA-specific IgE and local T cell infiltration were reduced, but they did not reach significant values.. These results suggest that IL-16 was both systemically and locally upregulated in the murine allergic rhinitis model and that IL-16 changed in parallel to allergic state by treatment with the drugs.

Topics: Animals; Anti-Allergic Agents; Carbazoles; Disease Models, Animal; Eosinophils; Female; Immunoglobulin E; Interleukin-16; Mice; Mice, Inbred BALB C; Nasal Mucosa; Ovalbumin; Platelet Aggregation Inhibitors; Rhinitis, Allergic, Perennial; Sulfonamides; Terfenadine

This study was undertaken to investigate the involvement of cyclooxygenase-2 (COX-2) in allergic nasal inflammation in actively sensitized rats. An allergic rhinitis model was developed by the repeated topical application of antigen into the nasal cavities in the sensitized rats. The severity of allergic rhinitis was studied by measuring the nasal behavior, as well as electroencephalogram (EEG) activity by antigen challenge. The electrodes were implanted chronically into the bilateral olfactory bulb of the rats and the EEG was measured monopolarly with an electroencephalograph (EEG, Nohon Kohden, Japan). The intranasal application of antigen caused the increase of nasal allergic signs as well as an EEG spike in a dose-dependent fashion, and at a dose of 50 microg/site, it showed a significant effect. The responses induced by the antigen were evaluated with certain drugs, etodolac (a selective COX-2 inhibitor), indomethacin (a non-selective COX inhibitor), ramatroban (a thromboxane A2 receptor antagonist) and zafirlukast (a cys-leukotriene receptor antagonist). Etodolac showed the inhibition of nasal behavior and EEG spike in a dose-related fashion, and at doses of 3 and 10 mg/kg, it showed a significant effect. Moreover, ramatroban also caused the dose-related inhibition of nasal behavior and EEG spike induced by antigen. On the other hand, both indomethacin and zafirlukast had no effects on the responses induced by antigen, even at a higher dose. Therefore, it can be concluded that cyclooxygenase-2 actively participates in the allergic nasal inflammation in actively sensitized rats.

Topics: Animals; Carbazoles; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Disease Models, Animal; Electroencephalography; Etodolac; Hypersensitivity; Indoles; Indomethacin; Leukotriene Antagonists; Male; Olfactory Bulb; Ovalbumin; Phenylcarbamates; Rats; Rats, Wistar; Receptors, Thromboxane A2, Prostaglandin H2; Rhinitis; Sneezing; Sulfonamides; Tosyl Compounds

Allergic rhinitis is an inflammatory disease of the nasal mucosa, induced by histamine, leukotrienes, and other substances released from mast cells. Fexofenadine hydrochloride, the active metabolite of terfenadine, is a novel, nonsedating antiallergic drug having H1 receptor antagonistic activity. Fexofenadine is effective for the treatment of allergic rhinitis. However, its mechanism of action in attenuating nasal congestion has not yet been elucidated. Therefore, we first examined the effects of fexofenadine on a guinea pig model of antigen-induced rhinitis. We also evaluated the effects of mepyramine, zafirlukast and ramatroban in this model; these drugs are an H1 receptor antagonist, a selective leukotriene antagonist and a selective thromboxane antagonist, respectively. Rhinitis was induced by ovalbumin (OVA) instillation into the nasal cavity of animals that had been sensitized by two earlier OVA injections (s.c. and i.p.). The nasal airway resistance was measured for 45 min after the challenge. Fexofenadine hydrochloride (20 mg/kg) and terfenadine (20 mg/kg) administered orally 70 min prior to the challenge significantly inhibited (fexofenadine, p < 0.001, terfenadine, p < 0.05) the increase in nasal airway resistance. Ramatroban (30 mg/kg) administered orally 60 min prior to the challenge also significantly inhibited (p < 0.05) the increase in nasal airway resistance. In contrast, mepyramine (3 mg/kg i.v.) and zafirlukast (3 mg/kg p.o.) failed to reduce the increase in nasal airway resistance. These results suggest that thromboxane may be involved in the increase in the nasal airway resistance in this model. Accordingly, fexofenadine may reduce the increase in nasal airway resistance by inhibiting the release of chemical mediators, including thromboxane, that are involved in the increase in nasal airway resistance in this model.

Topics: Airway Resistance; Animals; Anti-Allergic Agents; Area Under Curve; Carbazoles; Disease Models, Animal; Guinea Pigs; Indoles; Leukotrienes; Male; Ovalbumin; Phenylcarbamates; Pyrilamine; Rhinitis; Sulfonamides; Terfenadine; Thromboxanes; Tosyl Compounds

In the present study, we investigated the participation of chemical mediators in the development of experimental allergic conjunctivitis in rats. Cetirizine (a histamine H1 receptor antagonist), ramatroban (a thromboxane A2 (TXA2) receptor antagonist) and zafirlukast (a cysteinyl leukotrienes (cys-LTs) receptor antagonist) were orally administered from day 14 to day 42 during repeated topical antigen challenge. An increase in reactivity to antigen- and histamine-induced eye scratching behavior was observed by topical sensitization in sensitized rats. Although increased reactivity to antigen was not influenced by cetirizine, ramatoroban and zafirlukast, increased reactivity to histamine was significantly inhibited by ramatroban. The development of conjunctival edema was also observed for topical sensitization. Cetirizine caused no inhibition of the development of conjunctival edema, but ramatroban and zafirlukast inhibited the development of conjunctival edema. In addition, the number of eosinophils in the conjunctiva was increased by topical sensitization. Cetirizine had no significant effect on the increase in the number of eosinophils. However, ramatroban and zafirlukast were effective in inhibiting an increase in the number of eosinophils induced by topical sensitization. These results indicate that TXA2 is involved in increased histamine reactivity, and TXA2 and cys-LTs are associated with not only the conjunctival edema but also eosinophil infiltration during the development of experimental allergic conjunctivitis in rats.

Topics: Administration, Oral; Animals; Carbazoles; Cetirizine; Conjunctivitis, Allergic; Disease Models, Animal; Edema; Eosinophilia; Histamine H2 Antagonists; Indoles; Leukotriene Antagonists; Male; Membrane Proteins; Ovalbumin; Phenylcarbamates; Pruritus; Rats; Rats, Wistar; Receptors, Histamine H2; Receptors, Leukotriene; Receptors, Thromboxane A2, Prostaglandin H2; Sulfonamides; Tosyl Compounds

The purpose of this study was to investigate the involvement of chemical mediators other than histamine in nasal allergic signs using histamine H(1) receptor-deficient mice. In passively sensitized mice, antigen instillation into the nasal cavity induced significant increases in sneezing and nasal rubbing in wild-type mice, but no such increases were observed in histamine H(1) receptor-deficient mice. In actively sensitized mice, both sneezing and nasal rubbing were also significantly increased in a dose-dependent manner in both wild-type and histamine H(1) receptor-deficient mice. Histamine H(1) receptor antagonists such as cetirizine and epinastine significantly inhibited antigen-induced nasal allergic signs in wild-type mice, although the effects were incomplete. In addition, the thromboxane A(2) receptor antagonist ramatroban also inhibited these responses in wild-type mice. However, the leukotriene receptor antagonist zafirlukast showed no effects in wild-type mice. These results suggested that in the acute allergic model (passive sensitization), only histamine H(1) receptors are related to nasal signs induced by antigen, whereas in the chronic allergic model (active sensitization), both histamine H(1) receptors and thromboxane A(2) receptors were involved in the responses.

Topics: Animals; Anti-Allergic Agents; Antigens; Behavior, Animal; Carbazoles; Cetirizine; Dose-Response Relationship, Drug; Female; Histamine H1 Antagonists; Immunization; Immunoglobulin E; Indicators and Reagents; Indoles; Leukotriene Antagonists; Mice; Mice, Knockout; Ovalbumin; Passive Cutaneous Anaphylaxis; Phenylcarbamates; Receptors, Histamine H1; Rhinitis, Allergic, Seasonal; Sneezing; Sulfonamides; Thromboxane A2; Tosyl Compounds