Involvement of nitric oxide in pollen-induced biphasic nasal blockage in sensitised guinea pigs

Longitudinal study of effects of oral dosage of Bifidobacterium bifidum G9-1 on Japanese cedar pollen-induced allergic nasal symptoms in guinea pigs

Previous studies using experimental animal models have reported the beneficial effects of probiotics on allergic responses; however, their long-term effects on allergic nasal symptoms in clinical settings have not yet been elucidated in detail. In the present study, a guinea pig allergic rhinitis model involving repeated inhalation challenges with a natural allergen, Japanese cedar pollen, was used to examine the longitudinal effects of Bifidobacterium bifidum G9-1 (BBG9-1) on allergic nasal symptoms. BBG9-1 was administered orally once a day. Amelioration of nasal blockage was consistently observed throughout the experimental period in the BBG9-1-treated group. Although challenge-induced sneezing was not significantly inhibited in the BBG9-1-treated group, prolonged treatment with BBG9-1 slightly reduced the frequency of sneezing. Antigen-specific IgE antibody production was also not inhibited in the BBG9-1-treated group. Increases in the numbers of eosinophils and neutrophils in nasal cavity lavage fluid collected after pollen challenge were almost completely suppressed by BBG9-1 treatment, whereas those in mast cell mediators, histamine and cysteinyl leukotrienes were not. In contrast, increases in the levels of nitric oxide metabolites were potently suppressed. Furthermore, prolonged BBG9-1 treatment markedly suppressed exogenous leukotriene D4 -induced nasal blockage. Thus, prolonged oral administration of BBG9-1 suppresses Japanese cedar pollen-induced allergic nasal symptoms. The inhibitory mechanisms responsible may involve reductions in the responsiveness of target organs, such as endothelial cells in nasal mucosal blood vessels, to chemical mediators.

Inducible nitric oxide synthase plays important roles in allergic reactions of pollinosis in mice sensitized with pollen allergy

To elucidate the possible involvement of nitric oxide (NO) derived from inducible NO-synthase (iNOS) in the pathogenesis of patients with allergic rhinitis, we analyzed changes in the frequency of sneezing, plasma levels of NO metabolites, α-melanocyte-stimulating hormone (MSH) and immunoglobulin E and tracheal expression of IgA and mast cell tryptase in control and iNOS^−/− mice. Eight-week-old control and iNOS^−/− male C57BL/6j mice were sensitized with Cry j I antigen. After the last intranasal challenge of antigen, changes in the frequency of sneezing and plasma levels of IgE, α-MSH and NO metabolites and tracheal expression of iNOS, IgA and mast cell tryptase were analyzed by ELISA and immunohistochemistry using specific antibodies. The sensitization of mice with Cry j I antigen increased plasma levels of NO metabolites, α-MSH and IgE and tracheal expression of iNOS, IgA and mast cell tryptase in control not but in iNOS^−/− mice. Administration of N^G-nitro-L-arginine methyl ester strongly inhibited all these changes occurred in control mice. These results indicate that the symptom of pollinosis including sneezing is enhanced by iNOS derived NO through activation of α-MSH-receptor containing mast cells enriched with tryptase.

Effect of Ganoderma lucidum on pollen-induced biphasic nasal blockage in a guinea pig model of allergic rhinitis

Ganoderma lucidum (GL), an oriental medical mushroom, has been used in Asia for the prevention and treatment of a variety of diseases. However, the effect of GL on allergic rhinitis has not been well defined. The current study describes the inhibitory effect of GL on the biphasic nasal blockage and nasal hyperresponsiveness induced by repeated antigen challenge in a guinea pig model of allergic rhinitis. Intranasally sensitized guinea pigs were repeatedly challenged by inhalation of Japanese cedar pollen once every week. Ganoderma lucidum was orally administered once daily for 8 weeks from the time before the first challenge. The treatment with GL dose-dependently inhibited the early and late phase nasal blockage at the fifth to ninth antigen challenges. Furthermore, nasal hyperresponsiveness to intranasally applied leukotriene D₄ on 2 days after the eighth antigen challenge was also inhibited by the treatment with GL. However, Cry j 1-specific IgE antibody production was not affected by the treatment. In conclusion, we demonstrated that the pollen-induced biphasic nasal blockage and nasal hyperresponsiveness were suppressed by the daily treatment with GL in the guinea pig model of allergic rhinitis. These results suggest that GL may be a useful therapeutic drug for treating patients with allergic rhinitis.

Inhibition of hematopoietic prostaglandin D synthase improves allergic nasal blockage in guinea pigs

Although it has been suggested that prostaglandin (PG) D(2) is involved in the pathogenesis of allergic rhinitis, whether the inhibition of hematopoietic PGD(2) synthase (H-PGDS) shows beneficial effects on allergic rhinitis has been unclear. We evaluated the effects of a selective H-PGDS inhibitor, TFC-007, on nasal symptoms on Japanese cedar pollen-induced allergic rhinitis of guinea pigs. Sensitized animals were challenged with the pollen once a week. TFC-007 (30mg/kg, p.o.) given once before a challenge almost completely suppressed PGD(2) production in the nasal tissue early and late after the challenge. Although pre-treatment did not affect the incidences of sneezing and early phase nasal blockage, late phase nasal blockage was partially but significantly attenuated; however, nasal eosinophilia was not suppressed. In contrast, when TFC-007 was given once 1.5h after the challenge, the late phase response was not affected. Collectively, PGD(2) produced by H-PGDS early after an antigen challenge can participate in the induction of late phase nasal blockage, although the mechanism may be independent of eosinophil infilatration. The strategy for H-PGDS inhibition may be beneficial for allergic rhinitis therapy.

Involvements of cysteinyl leukotrienes and nitric oxide in antigen-induced venodilatation of nasal mucosa in sensitized rats in vivo

To determine an in vivo venodilatation of nasal mucosa, which is thought to be one of the causes of nasal obstruction in allergic rhinitis, venous diameters of nasal septa were directly measured in anesthetized rats. An application of antigen to nasal mucosa of sensitized rats caused an increase in diameters of mucosal veins, that is, venodilatation: the maximal response (about 20% increase in diameters) was observed at 55 min after antigen challenge. The antigen-induced increase in venous diameter of nasal mucosa was significantly inhibited by pretreatment with a cysteinyl leukotrienes (CysLTs) receptor antagonist, SR2640, and a nitric oxide (NO) synthase inhibitor, N(G)-monomethyl-L-arginine, indicating that CysLTs and NO might be involved in the venodilatation of nasal mucosa induced by antigen challenge. Blocking the action of CysLTs and NO might be therefore useful for the therapy of nasal obstruction in allergic rhinitis.

Differential responses to various classes of drugs in a model of allergic rhinitis in guinea pigs

Different drugs from various pharmacological classes were compared for their ability to protect against the nasal effects of acute allergen challenge in a guinea pig model. In the model, sneezing and nose rubbing were recorded after an initial allergen challenge in guinea pigs previously sensitized to egg albumin. Four days later the same guinea pigs were re-challenged a second time when anesthetised. In these anaesthetized animals, nasal airway pressure, pulmonary inflation pressure and cellular infiltration into nasal lavage fluid were measured. The drug tested were autacoid antagonists (mepyramine--3mg/kg, cetirizine--3mg/kg and montelukast--10mg/kg), L-NAME (10 or 20mg/kg), heparin (20mg/kg) and dexamethasone (20mg/kg) given either intraperitoneally or intravenously; all were given shortly before challenge. Sneezing induced by allergen challenge was statistically significantly reduced by mepyramine, cetirizine and dexamethasone whereas only cetirizine reduced nose rubbing. Changes in nasal airway pressure due to allergen exposure were reduced by cetirizine, montelukast, L-NAME, and heparin, but not by mepyramine, nor dexamethasone. In the presence of L-NAME, nasal airway pressure actually changed in the opposite direction. Cellular infiltration, as assessed by cytometry in nasal lavage fluid 60min after acute allergen challenge, was reduced by montelukast and heparin but not by antihistamines, L-NAME nor dexamethasone. This pattern of effects of the drugs, given by doses and routes previously described in the literature as being effective was not completely consistent with expected responses. The lack of effect of dexamethasone probably reflects the fact that it was given acutely whereas in the clinic chronic administration is used. The two antihistamines were not identical in their actions, presumably reflecting the fact that cetirizine has therapeutic actions not entirely confined to blockade of H1 receptors. Montelukast has not been reported to have major effects on sneezing and itching in the clinic but reduces nasal obstruction (lower nasal airway pressure or nasal patency). Montelukast's effects on cellular infiltration indicate the possible involvement of leukotrienes. Heparin has actions on inflammatory cell infiltration. This could explain its profile of reducing both cellular infiltration, and increased nasal airway pressure.

Effect of a Chinese herbal formula, Shi-Bi-Lin, on an experimental model of allergic rhinitis

BACKGROUND

Jia Wei Cang Er Zi San, a traditional Chinese herbal formula, has been used to treat allergic rhinitis (AR) for several centuries. However, its effect on experimental animal models and its therapeutic mechanism remain unclear.

OBJECTIVE

To study the effect of Shu-Bi-Lin, a modified Jia Wei Cang Er Zi San, on an animal model of AR.

METHODS

Shu-Bi-Lin was administered to the guinea pig model of AR. Meanwhile, an antihistamine-treated group for the treatment control, an ovalbumin-sensitized and untreated group for the positive control, and a sham-sensitized, sham-challenged group for the sham control were studied in parallel. Symptomatic and some pathophysiologic variables were evaluated.

RESULTS

Sneezing and nasal scratching after challenges were significantly ameliorated in the Shu-Bi-Lin-treated group compared with the ovalbumin-sensitized and untreated group, but rhinorrhea volume was not reduced. Shu-Bi-Lin significantly suppressed the production of IgG1 in the passive cutaneous anaphylaxis test. The thromboxane B2 level in nasal lavage fluid was significantly deceased in the Shu-Bi-Lin-treated group; however, the reduction in histamine and peptide leukotriene levels did not reach statistical significance. In addition, eosinophil infiltration and endothelial nitric oxide synthase immunoreactivity in the nasal tissues were reduced in the Shu-Bi-Lin-treated group.

CONCLUSIONS

Shu-Bi-Lin could alleviate the nasal symptoms of AR, and its mechanism might be related to its inhibitory effect on type I anaphylaxis reactions and eosinophil infiltration in the nasal tissues, as well as the inhibition of some mediators related to AR.

Effects of fexofenadine hydrochloride in a guinea pig model of antigen-induced rhinitis

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.

Synergism between cysteinyl leukotrienes and thromboxane A2 to induce allergic late phase nasal blockage in guinea pigs

We examined whether cysteinyl leukotrienes (CysLTs) and thromboxane (TX) A2 are synergistically involved in a cedar pollen-induced allergic late phase nasal blockage in guinea pigs. Sensitized animals were repeatedly challenged by pollen inhalation once every week. Combined treatment with pranlukast (a CysLT antagonist) and seratrodast (a TXA2 antagonist) inhibited late phase nasal blockage, but the magnitude of inhibition (approximately 50%) was equal to those of the respective single treatments, suggesting that CysLTs produced late after challenge induces TXA2 production in the nasal tissue, as in the case of the lung of this species. However, pranlukast did not affect TXB2 increase in the nasal tissue. In contrast, combined intranasal instillation of LTD4 and U-46619 (a TXA2 mimetic) produced much greater nasal blockage than single administration of each agonist in sensitized animals. Therefore, allergic late phase nasal blockage should be induced by synergistic activity of CysLTs and TXA2 at the effector organ.

Effect of Oral Immunotherapy on Nasal Blockage in Experimental Allergic Rhinitis

We previously reported that when Japanese cedar pollen was prophylactically p.o. administered before a sensitization stage in a guinea-pig model of allergic rhinitis, pollen-induced nasal blockage was suppressed. In this study, we evaluated whether the oral immunotherapy is also effective when the pollen extract was administered starting from the day when the nasal blockage was clearly induced and whether the effectiveness continued after cessation of the immunotherapy. Sensitized animals were repeatedly challenged by pollen inhalation once every week. After the 7th challenge, the extract was orally administered twice a week until the 30th challenge. At the 11th challenge, the oral immunotherapy showed inhibition of the biphasic nasal blockage. The effectiveness was consistently observed during the immunotherapy until the 30th challenge. Furthermore, the increased nasal responsiveness to intranasal application of leukotriene D4 was markedly suppressed by the immunotherapy. Interestingly, even after cessation of the therapy, inhibition of the nasal blockage was sustained for more than 2 months. Nevertheless, neither sneezing nor antigen-specific IgE antibody production was substantially influenced by the immunotherapy. In conclusion, Oral immunotherapy may be clinically useful for allergic nasal blockage. Mechanisms underlying the effectiveness may be associated with the hyporesponsiveness of the nasal mucosa to released mediators.

Acquired nasal hyperresponsiveness aggravates antigen-induced rhinitis in the guinea pig

Whether a state of nasal hyperresponsiveness influences antigen-induced biphasic nasal blockage and sneezing were examined using a guinea pig model of allergic rhinitis. Sensitized animals were challenged with an antigen, Japanese cedar pollen, once every week. Before the 13th challenge, the animals were randomly divided into 2 groups, and then the 13th challenge was performed (Groups A-0 and B-0). The 14th challenge was done on day 2 (Group A-2) and on day 7 (Group B-7) after the 13th challenge, on which nasal hyperresponsiveness was present and absent, respectively. Biphasic nasal blockage and sneezing after the challenge in Group A-2 were more severe than those in Group A-0, while those of Group B-7 were almost the same as those of Group B-0. An anti-histaminic, mepyramine, inhibited sneezing but not the biphasic nasal blockage in Group B-7. A cysteinyl leukotriene (CysLT) antagonist, pranlukast, suppressed the late nasal blockage but not the early blockage and sneezing in Group B-7. In contrast, in Group A-2, mepyramine significantly attenuated not only sneezing but also the early nasal blockage. Pranlukast significantly inhibited both nasal blockage and sneezing in Group A-2. In conclusion, nasal hyperresponsiveness aggravated the antigen-induced nasal responses, to which histamine and CysLTs considerably contributed.

Characterization of nasal obstruction in the allergic guinea pig using the forced oscillation method

INTRODUCTION

This is the first report to evaluate changes in nasal resistance in a preclinical animal model using the forced oscillation method.

METHODS

The method involves characterizing pressure-flow relationships of the respiratory system due to external oscillatory forces.

RESULTS

First, we evaluated changes in nasal resistance using an established small-animal rhinometric technique. In these studies, aerosolized ovalbumin (3%) administered to the nasal cavity of ovalbumin-sensitized guinea pigs increased nasal resistance at 30 min by 99 +/- 14%. The histamine H1 antagonists, chlorpheniramine (1 mg/kg i.v.) and pyrilamine (1 mg/kg i.v.), blocked the increase in nasal resistance due to ovalbumin provocation (50 +/- 17% and 39 +/- 11% over baseline, respectively). The alpha-adrenergic agonist phenylpropanolamine (3 mg/ kg i.v.) had no effect on the nasal actions of ovalbumin. In separate studies, nasal resistance was measured at 2 Hz by forced oscillation and ovalbumin (3%) increased nasal resistance by 91 +/- 14%. Chlorpheniramine (1 mg/kg i.v.) significantly attenuated the increase in nasal resistance due to ovalbumin. Finally, changes in nasal resistance for each treatment group were evaluated at frequencies of 1 - 18 Hz. Area under the curve analysis demonstrated that chlorpheniramine blocked the nasal obstructive effect of ovalbumin. In contrast, a pharmacologically active dose of phenylpropanolamine (3 mg/kg i.v.) did not produce decongestant activity.

DISCUSSION

The current data are inconsistent with the well-established clinical efficacy of alpha-adrenergic agonists as nasal decongestants. Consequently, we suggest that allergic nasal obstruction in the guinea pig may not be the best preclinical approach to assess the nasal decongestant activity of vasoconstrictor alpha-adrenergic agonists. Additionally, our studies demonstrate the utility of the forced oscillation technique in assessing changes in nasal resistance in small laboratory animals.

Effects of TAK-427 on acute nasal symptoms and nasal obstruction in guinea pig model of experimental allergic rhinitis

TAK-427 (2-[6-[[3-[4-(diphenylmethoxy)piperidino]propyl]amino]imidazo[1,2-b]pyridazin-2-yl]-2-methylpropionic acid dihydrate) is a novel anti-allergic agent that has both histamine H1-receptor antagonist and anti-inflammatory activities. In this study, we evaluated the efficacy of TAK-427 on acute nasal responses and nasal obstruction using various guinea pig models of allergic rhinitis. TAK-427 inhibited the histamine-induced nasal reactions with an ID50 value of 0.633 mg/kg, p.o. TAK-427 (0.1-10 mg/kg, p.o.) and most histamine H1-receptor antagonists tested inhibited the increase in intranasal pressure, nasal hypersecretion, sneezing and nasal itching caused by a single antigen challenge in sensitized guinea pigs. In addition, TAK-427 (0.3, 30 mg/kg, p.o.) significantly inhibited the development of nasal obstruction when sensitized guinea pigs were repeatedly challenged via inhalation with Japanese cedar pollen, whereas the histamine H1-receptor antagonist, azelastine (1 mg/kg, p.o.), and ketotifen (1 mg/kg, p.o.) were without effect. These results suggest that TAK-427 might not only suppress acute nasal symptoms but also ameliorate nasal obstruction via the effects other than those as a histamine H1-receptor antagonist.

Kinins are involved in the development of allergic nasal hyperresponsiveness in guinea pigs

We evaluated roles of kinins in allergen-induced nasal blockage and sneezing, and development of nasal hyperresponsiveness to leukotriene D4 in a Japanese cedar pollen-induced allergic rhinitis model of guinea pigs. Sensitised guinea pigs were repeatedly challenged by pollen inhalation once every week. Neither a bradykinin B1 receptor antagonist, des-Arg9-[Leu8]bradykinin nor a bradykinin B2 receptor antagonist, icatibant suppressed allergen-induced sneezing and nasal blockage. However, development of nasal hyperresponsiveness to leukotriene D4 was significantly suppressed by them. The amount of bradykinin in nasal cavity lavage fluid was immediately increased after the challenge. In non-sensitised animals, hyperresponsiveness to leukotriene D4 was developed by a bradykinin B2 receptor agonist, bradykinin, but not by a bradykinin B1 receptor agonist, des-Arg10-kallidin, while in the sensitised-challenged animal, both agonists developed hyperresponsiveness. In conclusion, the nasal hyperresponsiveness appeared to be induced by kinins produced in response to the antigen challenge through activation of not only bradykinin B2 but also B1 receptors.

Multiple Cedar Pollen Challenge Diminishes Involvement of Histamine in Allergic Conjunctivitis of Guinea Pigs

It has been reported that antihistamines do not fully modify symptoms of allergic conjunctivitis in clinical settings, suggesting that histamine is not the only contributor to symptom generation in the disease. However, in the majority of experimental allergic conjunctivitis models, antihistamines are very effective in the reduction of symptoms. In the present study, we used our recently developed guinea pig model of allergic conjunctivitis and evaluated whether involvement of histamine in the induction of symptoms of allergic conjunctivitis is altered by multiple antigen challenges. Guinea pigs were sensitized by intraperitoneal injection of Japanese cedar pollen extracts adsorbed on aluminum hydroxide gel, and then challenged by dropping a pollen suspension without the adjuvant on each eye once a week until the 15th challenge. The magnitude of the conjunctivitis intensity score (CIS), itch-associated scratching response and albumin leakage were found to increase with repeated challenges. At the 1st-3rd challenges, histamine H(1) receptor antagonist, mepyramine (10 mg/kg, p.o.), strongly reduced all these symptoms. However, symptoms at the 5th-15th challenges were not inhibited by mepyramine. On the other hand, a nitric oxide synthase (NOS) inhibitor, N(omega)-nitro-L-arginine methyl ester (10 mg/kg, i.v.), potently inhibited the increase of CIS and albumin leakage at the 15th challenge. In conclusion, histamine involvement in the induction of conjunctivitis symptoms in our model was diminished by multiple antigen challenges. The allergic conjunctivitis at the chronic stage is partly mediated by nitric oxide (NO) derived from NOSs that may be activated by mediators other than histamine. The histamine-independent allergic conjunctivitis may be useful for analyzing mechanisms underlying chronic conjunctivitis.