Rat Model Of Allergic Rhinitis Research Articles

The role of endothelin-1 and endothelin receptor antagonists in allergic rhinitis inflammation: ovalbumin-induced rat model

Desloratadine is a biologically active metabolite of loratadine which is indicated for the treatment of allergic rhinitis. Bosentan is a dual endothelin receptor antagonist used to treatment of pulmonary artery hypertension (PAH). In this study, we aimed to determine the role of endothelins in allergic rhinitis (AR) and the effects of endothelin receptor antagonists in AR rat models through comparison with desloratadine. In total, 20 adult Sprague-Dawley rats were used in this study. An ovalbumin-induced allergic rhinitis model was formed in three study groups except for the control group. Bosentan (100 mg/kg/day) was given to the bosentan-treated group for 7 days and desloratadine (10 mg/kg/day) was administered to the antihistaminic-treated group for 7 days. Nasal symptom scorings and histopathological examinations of the nasal tissues were carried out. Serum IgE levels and ET-1 and TNF-alpha mRNA expression levels were analysed. Between group comparisons for nasal symptoms, histopathological analysis, and molecular analyses were performed with a one-way ANOVA and Duncans multiple comparison tests. Significance was accepted at p smaller than 0.05. Bosentan inhibited nasal symptom more significantly than desloratadine. The IgE level, ET-1 and TNF-alpha mRNA expression levels statistically increased in the allergic rhinitis group when compared to other groups. Conversely, the bosentan-treatment group showed a significant recovery from the same parameters. The deterioration in histopathological parameters reached the highest levels in the allergic rhinitis group. The histopathological findings were close to those of the control group in the bosentan and antihistaminic-treated group. ET-1 is one of the mediators that impact AR development and ET-1 antagonists can be useful for symptom control and for decreasing allergic inflammation in AR patients.

Mahuang Fuzi Xixin Decoction Attenuates Th1 and Th2 Responses in the Treatment of Ovalbumin-Induced Allergic Inflammation in a Rat Model of Allergic Rhinitis.

Allergic rhinitis (AR) is one of the most common allergic diseases, which adversely affect patients' quality of life. Mahuang Fuzi Xixin decoction (MFXD) has been widely used to treat AR in clinics in Asian countries. This study investigated the effect and possible therapeutic mechanisms of MFXD in the treatment of AR. A Wistar rat model of ovalbumin- (OVA-) induced AR was established and then treated with three doses of MFXD; AR symptoms, serum total immunoglobulin E, histamine, histopathological features, and release and expression of factors related to type 1 helper T (Th1) and type 2 helper T (Th2) responses were analyzed. Our study demonstrated that MFXD has a good therapeutic effect on OVA-induced allergic inflammation in an AR rat model as manifested in reduced frequencies of sneezing and nasal scratching and in reduced serum levels of total IgE and HIS. In addition, MFXD regulates imbalance in Th1/Th2 cells caused by AR by simultaneously attenuating Th1 and Th2 responses, such as by reducing the serum levels of IFN-γ and IL-4 and mRNA expression levels of IFN-γ, IL-4, GATA-3, and STAT-6. This study provided valuable information on the immunoregulatory effect of MFXD for the treatment of AR in future clinical studies.

Inhibitory Effect of Pycnogenol® on Airway Inflammation in Ovalbumin-Induced Allergic Rhinitis.

The supplement Pycnogenol® (PYC) has been used for the treatment of several chronic diseases including allergic rhinitis (AR). However, the in vivo effects on allergic inflammation have not been identified to date. To investigate the treatment results of PYC on allergic inflammation in a rat model of allergic rhinitis. Animal experimentation. Allergic rhinitis was stimulated in 42 rats by intraperitoneal sensitization and intranasal challenge with Ovalbumin. The animals were divided into six subgroups: healthy controls, AR group, AR group treated with corticosteroid (dexamethasone 1 mg/kg; CS+AR), healthy rats group that were given only PYC of 10 mg/kg (PYC10), AR group treated with PYC of 3mg/kg (PYC3+AR), and AR group treated with PYC of 10 mg/kg (PYC10+AR). Interferon-γ (IFN-γ), interleukin-4 (IL-4), interleukin-10 (IL-10), and OVA-specific immunoglobulin E (Ig-E) levels of serum were measured. Histopathological changes in nasal mucosa and expression of tumor necrosis factor-α (TNF-α) and IL-1β were evaluated. The levels of the IL-4 were significantly decreased in the PYC3+AR, PYC10+AR and CS+AR groups compared with the AR group (p=0.002, p<0.001, p=0.006). The production of the IFN-γ was significantly decreased in the PYC3+AR and PYC10+AR groups compared with the AR group (p=0.013, p=0.001). The administration of PYC to allergic rats suppressed the elevated IL-10 production, especially in the PYC3+AR group (p=0.006). Mucosal edema was significantly decreased respectively after treatment at dose 3 mg/kg and 10 mg/kg PYC (both, p<0.001). The mucosal expression of TNF-α has significantly decreased in the PYC3+AR and PYC10+AR groups (p=0.005, p<0.001), while the IL-1β expression significantly decreased in the CS+AR, PYC3+AR, and PYC10+AR groups (p<0.001, p=0.003, p=0.001). PYC has multiple suppressive effects on allergic response. Thus, PYC may be used as a supplementary agent in allergic response.

Immune modulation of shikonin in a rat allergic rhinitis model

Objective:To study intervention effect of shikonin on immune function of dendritic cells using a rat allergic rhinitis model.Method: Forty rats were divided into three groups include OVA group(n=15),OVA+ shikonin group(n=15), and control group(n=10).The rat allergic rhinitis model was estabilshed after OVA sensitization and local challenge. 100 μg/ml shikonin was spray inhalated after OVA challenge in OVA+ shikonin group. The expression of CD80,CD86,IL-10 and IL-12 was deteced by immunohistochemistry in three groups.Result: In OVA+ shikonin group, the CD80 value was 13.52± 3.53,CD86 value was 24.01±13.12;in OVA group, the CD80 value was 17.19± 4.42 and the CD86 value was 38.89±9.77.The IL-10 value was 6.69±1.12 and 3.61± 0.23 in OVA group and OVA+ shikonin group,respectively.The IL-12 value was 44.30± 9.70 and 28.80+8.20 in OVA group and OVA+ shikonin group,respectively.Conclusion:The shikonin has effect on immune modulation in rat model of allergic rhinitis.

Denervation of nasal mucosa induced by posterior nasal neurectomy suppresses nasal secretion, not hypersensitivity, in an allergic rhinitis rat model

The posterior nasal nerve is the dominant source of the parasympathetic, sympathetic, and sensory fibers that innervate the nasal respiratory mucosa. Therefore, a posterior nasal neurectomy (PNN) is thought to induce denervation of the nasal mucosa and relieve the nasal symptoms of allergic rhinitis. However, the underlying mechanisms and therapeutic action of PNN remain unknown. To investigate the impact of PNN-induced denervation of the nasal mucosa on allergic rhinitis, we developed a rat model of PNN and examined the effects of PNN on allergic rhinitis in ovalbumin-sensitized rats. This rat model of PNN was characterized by the depletion of nerve fibers, choline acetyltransferase, and neuropeptides (eg, substance P, calcitonin gene-related peptide, vasoactive intestinal peptide, and neuropeptide Y) in the nasal respiratory mucosa. These animals exhibited nasal gland and goblet cell hypertrophy in the septal mucosa and atrophy of the submucosal gland in the lateral nasal wall, as well as reduced nasal secretion due to deficient acetylcholine synthesis. In an ovalbumin-sensitized model of allergic rhinitis, PNN also induced the depletion of nerve fibers, choline acetyltransferase, and neuropeptides in the nasal mucosa and suppressed nasal secretion. However, PNN did not affect mucosal thickening, eosinophil and mast cell infiltration, interleukin-4 and interferon-γ mRNA expression, and allergic symptoms (ie, sneezing and nasal scratching). These results suggest that the peripheral nerves and corresponding neuropeptides regulate nasal secretion, but not hypersensitivity, in allergic rhinitis, and that allergic rhinitis-related mucosal reactions occur in a highly denervated mucosa after PNN. Posterior nasal neurectomy may be a therapeutic option for the treatment of hyperrhinorrhea, but not allergic rhinitis hypersensitivity.

The role of endothelin-1 and endothelin receptor antagonists in allergic rhinitis inflammation: ovalbumin-induced rat model.

Desloratadine is a biologically active metabolite of loratadine which is indicated for the treatment of allergic rhinitis. Bosentan is a dual endothelin receptor antagonist used to treatment of pulmonary artery hypertension (PAH). In this study, we aimed to determine the role of endothelins in allergic rhinitis (AR) and the effects of endothelin receptor antagonists in AR rat models through comparison with desloratadine. In total, 20 adult Sprague-Dawley rats were used in this study. An ovalbumin-induced allergic rhinitis model was formed in three study groups except for the control group. Bosentan (100 mg/kg/day) was given to the bosentan-treated group for 7 days and desloratadine (10 mg/kg/day) was administered to the antihistaminic-treated group for 7 days. Nasal symptom scorings and histopathological examinations of the nasal tissues were carried out. Serum IgE levels and ET-1 and TNF-alpha mRNA expression levels were analysed. Between group comparisons for nasal symptoms, histopathological analysis, and molecular analyses were performed with a one-way ANOVA and Duncans multiple comparison tests. Significance was accepted at p smaller than 0.05. Bosentan inhibited nasal symptom more significantly than desloratadine. The IgE level, ET-1 and TNF-alpha mRNA expression levels statistically increased in the allergic rhinitis group when compared to other groups. Conversely, the bosentan-treatment group showed a significant recovery from the same parameters. The deterioration in histopathological parameters reached the highest levels in the allergic rhinitis group. The histopathological findings were close to those of the control group in the bosentan and antihistaminic-treated group. ET-1 is one of the mediators that impact AR development and ET-1 antagonists can be useful for symptom control and for decreasing allergic inflammation in AR patients.

Antioxidant activities of curcumin in allergic rhinitis

We investigated the antioxidant effects of curcumin in an experimental rat model of allergic rhinitis (AR). Female Wistar albino rats (n=34) were divided randomly into four groups: healthy rats (control group, n=8), AR with no treatment (AR+NoTr group, n=10), AR with azelastine HCl treatment (AR+Aze group, n=8), and AR with curcumin treatment (AR+Curc group, n=8). On day 28, total blood IgE levels were measured. For measurement of antioxidant activity, the glutathione (GSH) level and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities were measured in both inferior turbinate tissue and serum. Malondialdehyde (MDA) levels were measured only in inferior turbinate tissue, and paraoxonase (PON) and arylesterase (ARE) activities were measured only in serum. Statistically significant differences were found for all antioxidant measurements (GSH levels and CAT, SOD, GSH-Px activities in the serum and tissue, MDA levels in the tissue, and PON and ARE activities in the serum) between the four groups. In the curcumin group, serum SOD, ARE, and PON and tissue GSH values were higher than the control group. Moreover, tissue GSH levels and serum GSH-Px activities in the curcumin group were higher than in the AR+NoTr group. In the azelastine group, except MDA, antioxidant measurement values were lower than in the other groups. Curcumin may help to increase antioxidant enzymes and decrease oxidative stress in allergic rhinitis. We recommend curcumin to decrease oxidative stress in allergic rhinitis.

Effects of propolis in an experimental rat model of allergic rhinitis

PurposeThe aim of this study was to determine the anti-allergic activity of propolis in an ovalbumin-induced rat model of allergic rhinitis. Materials and methodsThis prospective experimental study was conducted at Hakan Çetinsaya Clinical and Experimental Animal Research Center with 30 rats. After sensitization of all rats with 0.3mg intraperitoneal ovalbumin plus 30mg aluminum hydroxide for 14days (first phase), rats were divided to five groups. In the second phase of the study 10μL of ovalbumin was applied to each nostril for 21days. Together with second phase, ketotifen (n:6), oral propolis (n:6), intranasal propolis (n:6) and intranasal mometasone furoate (n:6) were given to rats. A control group (n:4)(salin) and sham group (n:2) were planned. Symptoms were assessed on days 19, 22, 25, 30 and 35, resulting in 5 symptom scores: symptom scores 1–5. On day 35, nasal tissue was removed and histological examination was performed. ResultsWhen rats that received systemic and intranasal propolis were compared to controls, ciliary loss, inflammation, increase in goblet cells, vascular proliferation, eosinophil count, chondrocytes and allergic rhinitis symptom score were found to be decreased (p<0.05). ConclusionsIt was found that propolis had anti-allergic effects on allergic symptom scores and nasal histology.

Cinnamaldehyde is an effective anti-inflammatory agent for treatment of allergic rhinitis in a rat model

ObjectivesThe effect of cinnamaldehyde on the treatment of allergic rhinitis (AR) was investigated in rat model. MethodsTwenty-eight female Wistar albino rats were randomly divided into four groups: Group 1 (control) (C), Group 2 (AR with no treatment) (AR+NoTr), Group 3 (AR+Azelastine HCl) (AR+Aze), and Group 4 (AR+cinnamaldehyde) (AR+Cin). At day 21, AR+Aze rats were given an Azelastine HCl drop, and AR+Cin rats were given cinnamaldehyde intranasally. In all groups, allergic symptoms histopathological results were evaluated. ResultsThe AR+NoTr group showed the worst allergic symptoms, cilia loss and greater inflammation. In the AR+Aze and AR+Cin groups, allergic symptom scores were higher than those in the control group. However, between AR+Aze and AR+Cin groups, there were no significant differences in the allergic symptom scores Histopathological analysis revealed vascular congestion and an increase in goblet cell numbers in the AR+Cin group. However, AR+Cin rat nasal mucosa had less plasma cell infiltration compared with the AR+NoTr group. In rats from the AR+Aze group, analysis of the nasal mucosa revealed less eosinophil infiltration than that seen in the AR+NoTr group. A lower score for mast cell (MC) infiltration was observed in the nasal mucosa of rats treated with Azelastine HCl compared with cinnamaldehyde. ConclusionsIn this study we observed that both Azelastine HCl and cinnamaldehyde reduced allergic symptoms in an AR rat model. Cinnamaldehyde decreased vascular congestion as well as plasma cell, eosinophil, and inflammatory cell infiltration into the lamina propria.

Effects of desloratadine citrate disodium injection on rat models of ovalbumin-induced allergic rhinitis: involvement of T-cell responses modulation.

Allergic rhinitis (AR) is a very common worldwide problem; patients display a number of symptoms, such as sneezing, nasal itching, and rhinorrhea, and their lifestyle is affected. Desloratadine is a novel, long-acting inhibitor of histamine. However, very little is known about the effect of desloratadine citrate disodium injection (DLC injection) on AR, and the underlying mechanisms are yet unexplored. Herein, we sought to explore the effects and mechanisms of actions of DLC injection in ovalbumin (OVA)-induced immune responses in a rat model of AR. Sixty rats were subjected to immunization with OVA (intraperitoneal [i.p.]), followed by a nasal challenge with OVA. Drugs or saline were given daily for treatment. Nasal symptoms and histology of the nasal mucosa were examined. Cytokines such as interleukin (IL)-4, IL-12, interferon (IFN)-γ, adhesion molecules such as soluble vascular cell adhesion molecule 1 (sVCAM-1), and inducible nitric oxide synthase (iNOS) expression were assessed by enzyme-linked immunosorbent assay (ELISA) kit. Nitric oxide (NO) concentration was also measured by NO assay kit. DLC treatment (intravenous [i.v.]) significantly decreased the frequency of sneezing and nasal scratching and alleviated nasal inflammation by increasing the serum levels of IFN-γ and IL-12, while lowering the expression of IL-4. Thus, DLC (i.v.) treatment led to a marked elevation in T-helper 1/T-helper 2 (Th1/Th2) ratio when administered in the AR rats. The expression of sVCAM-1, iNOS, and NO were also reversed. DLC (i.v.), given after an allergen challenge, improved Th1 cytokines level and restrained Th2 responses alleviating the symptoms of AR. Our results indicate that DLC injection may exhibit such effects through the modulation of T-cell responses.

Bencycloquidium bromide inhibits nasal hypersecretion in a rat model of allergic rhinitis.

This study is aimed at exploring the effect of Bencycloquidium bromide (BCQB), a novel M1/M3 receptor antagonist, on mucus secretion in a murine model of allergic rhinitis (AR). Sprague-Dawley rats were sensitized with ovalbumin to induce AR. After BCQB treatment, nasal symptoms were evaluated. Nasal lavage fluid was used to detect the protein level of cytokines and histamine by the method of enzyme-linked immunosorbent assay. The nasal mucosa of all animals was prepared for western blot, quantitative real-time polymerase chain reaction and histochemical analysis. BCQB could not only alleviate typical AR symptoms including rhinorrhea, nasal itching and sneezing, but also inhibit the overexpression of mucin 5AC at the level of protein and mRNA. The release of histamine, the mRNA and protein level of IL-6, IL-13 and TNF-α, and the nuclear translocation of NF-κB (p65 and p50) were inhibited by BCQB. In addition, histological studies showed BCQB dramatically inhibited ovalbumin-induced nasal lesions, eosinophil infiltration, aggregation of mast cells, globlet cell hyperplasia and metaplasia. BCQB attenuates mucus hypersecretion in AR, possibly involving in the NF-κB signaling pathway.

Expression and significance of NLRP3 inflammasome and its downstream factors IL-1β/IL-18 in rat model of allergic rhinitis

To detect the expression and explore the role of the innate immune NLRP3 inflammasome and its downstream factors interleukin-1β (IL-1β)/ interleukin-18 (IL-18) in rat model of allergic rhinitis (AR). Forty Sprague Dawley (SD) rats were randomly divided into control group (A group), AR model group 1 (B group), AR model group 2(C group), AR model group 3 (D group). Every group contained 10 rats. After the rats in the model group were sensitized by ovalbumin (OVA) and alum, B, C and D groups were separately stimulated with 5% OVA for 10 days, 20 days and 30 days (once a day). The control group did not add OVA in the process of sensitization and excitation. All rats were executed after excitation.Eosinophil granulocyte (EOS) infiltration were observed in nasal mucosa by hematoxylin-eosin (HE) staining, the expression of NLRP3 and cysteinyl aspartate-specific protease-1 (Caspase-1) were observed in nasal mucosa by immunohistochemical staining. The concentrations of ovalbumin specific IgE (OVA-sIgE), IL-18 and IL-1β in peripheral blood and the concentrations of IL-18 and IL-1β in nasal fluid were tested by enzyme-linked immunosorbent assay (ELISA). The data were processed by SPSS 17.0 software. EOS cell counted, the behavioral score and the concentrations of OVA-sIgE in AR model group were obviously higher than those in control group (P < 0.05), and the difference of which had statistical significance between the AR model groups (P < 0.05). The expression of NLRP3 in AR model group (The expression of NLRP3 in group of B, C and D were 48.80 ± 10.75, 71.80 ± 16.98 and 100.32 ± 13.91, respectively) were obviously higher than those in control group (17.47 ± 5.59), the difference of which had statistical significance (F = 78.399, P < 0.05). The expression of Caspase-1 in AR model group (The expression of Caspase-1 in group of B, C and D were 36.33 ± 4.71, 50.87 ± 11.18 and 73.10 ± 14.77, respectively) were obviously higher than those in control group (11.48 ± 2.70), the difference of which had statistical significance (F = 71.727, P < 0.05). The concentrations of IL-1β in AR model group [The concentrations of IL-1β in group of B, C and D were (56.46 ± 10.13), (82.37 ± 11.93), (112.01 ± 22.91) pg/ml, respectively] were obviously higher than those in control group [(38.26 ± 4.66) pg/ml], the difference of which had statistical significance (F = 51.981, P < 0.05). The concentrations of IL-18 in AR model group [The concentrations of IL-18 in group of B, C and D were (177.92 ± 23.63), (194.33 ± 20.78), (234.06 ± 31.70) pg/ml, respectively] were obviously higher than those in control group [(89.71 ± 5.56) pg/ml], the difference of which had statistical significance (F = 73.295, P < 0.05). And the difference of which had statistical significance between the AR model groups (P < 0.05). The expression of NLRP3 was significantly positively correlated with the behavioral score, the concentrations of OVA-sIgE and EOS cell counted in rat model of allergic rhinitis (r value were 0.833,0.873 and 0.868, respectively, all P < 0.01). NLRP3 inflammasome and its downstream factors IL-1β/IL-18 play a role in the pathogenesis of allergic rhinitis, which may be correlated with the degree of inflammation.

N‐acetylcysteine exerts therapeutic action in a rat model of allergic rhinitis

The pathophysiologic mechanism of allergy is dependent on the action of many redox-sensitive proinflammatory mediators. However, even though redox disturbances are believed to be a hallmark of inflammation, little is known of the effect of redox imbalance to the pathophysiology of allergic rhinitis. We thus opted to investigate the relation of oxidative stress and allergic rhinitis, through the utilization of a potent antioxidant substance (N-acetylcysteine [NAC]) in a rat model of allergic rhinitis and the evaluation of its action on specific markers of inflammation. NAC (50 mg/kg and 250 mg/kg) was intraperitoneally administered to ovalbumin (OVA)-sensitized rats prior to intranasal challenge with OVA. Mucosal congregation of inflammatory cells (eosinophils and mast cells), mucosal expression of redox-sensitive enzymes (inducible nitric oxide synthase [iNOS] and cyclooxygenase 2 [COX-2]), and the blood levels of a key proinflammatory mediator (tumor necrosis factor-α [TNF-α]) were evaluated. Intranasal OVA challenges lead to mucosal inflammation, induction of the mucosal expression of iNOS and COX-2 and elevation of TNF-α blood levels. NAC significantly inhibited accumulation of inflammatory cells and downregulated iNOS expression and TNF-α serum levels. The role of COX-2 appeared to be 2-fold and its expression was divergently modulated by NAC. Our findings suggest that redox balance is involved in the pathophysiology of allergic rhinitis in rats and that NAC can potentially suppress the allergen-induced nasal inflammatory cascade. The investigation of the role of oxidative stress in atopy could help in the evaluation of the therapeutic potential of antioxidant substances in allergic diseases.

A Novel Botulinum Neurotoxin Topical Gel: Treatment of Allergic Rhinitis in Rats and Comparative Safety Profile

Rhinitis affects a significant proportion of adults and children with typically seasonal or chronic symptoms. Botulinum neurotoxin type A (BoNTA) is a well-known cholinergic antagonist widely used in a number of approved neurological and esthetic indications. This study was designed to assess the therapeutic effect of RT001, a novel topical gel formulation of BoNTA, in the treatment of allergic rhinitis using a rat model and to compare its safety profile with that of an aqueous formulation of BoNTA complex. A rat model of allergic rhinitis was used involving induction of classic rhinitis signs (sneezing and nasal itch) in addition to nasal inflammatory pathology to assess the degree of therapeutic effect of RT001. Comparative safety of RT001 and BoNTA complex was assessed in guinea pigs based on lethality and body weight gain. Clinical signs of rhinitis were significantly (p < 0.01) relieved after a single intranasal administration of RT001 and resolved to normal baseline levels within 5 days after treatment. Mucosal inflammation characterized by edema, congestion, and vascular dilatation along with increased expression of vasoactive intestinal peptide was noted in control animals after allergy induction, whereas RT001 treatment resolved inflammation to essentially normal baseline levels. Safety studies in guinea pigs via intranasal dosing revealed ∼31-fold greater safety factor for RT001 when compared with BoNTA complex. These results suggest that topical intranasal application of RT001 is effective in relief of clinical signs and inflammatory pathology associated with allergic rhinitis in a rodent model and may provide a safe treatment for rhinitis.

The effect of intranasal steroid on nasal mucosa in rat model of allergic rhinitis

To investigate the effects of intranasal steroid on nasal mucosa in rat model of allergic rhinitis (AR). Thirty-six SD rats were randomly divided into three groups (each included 12 rats): the intranasal steroid group(group A),the allergic rhinitis group(group B) and the normal control group(group C). AR model was reproduced by ovalbumin in group A and B. The control group was allergized by NS instead of ovalbumin. Group A was used steroid spray in nasal and Group B and C was used normal saline. Then ,after the last provocation,the allergic symptoms were evaluated,the number of eosinophil (EOS) of the rats' nasal mucosa was counted under hematoxylineosin staining and the goblet cells was counted under alcian blue-periodic acid-Schiff staining. The morphological changes of the rats' nasal mucosa were observed by scanning electron microscope. Compared with group B,the inhibition of nasal symptoms was found after used of steroid spray in group A. The EOS and the goblet cells in group A was significantly different with that in Group B (P < 0.05), but no significant differences compared with group C (P > 0.05). Observed by scanning electron microscope, the cilia of the epithelium in group B were significantly lodging, disoriented, winding and secreting,while the cilia of the epithelium in Group A and C had similar appearance. Intranasal steroid spray can relieve symptoms and inflammatory conditions of nasal mucosa in allergic rhinitis, and can repair injured nasal mucosa cilia.

Involvement of K + channels in the augmented nasal venous responsiveness to nitric oxide in rat model of allergic rhinitis

Objective One of the factors of nasal obstruction observed in allergic rhinitis is thought to be a dilatation of microveins in nasal mucosa, although the exact mechanism(s) is not fully understood. In nasal mucosae of repeatedly antigen challenged rats, NO-induced venodilatation itself is augmented. In the present study, the roles of K + channels in sodium nitroprusside (NO donor; SNP)-induced venodilatation of nasal mucosae in antigen-challenged rats were investigated. Methods Actively sensitized rats were repeatedly challenged with aerosolized antigen. Twenty-four hours after the final antigen challenge, nasal septum mucosa was exposed surgically and observed directly in vivo under a stereoscopic microscope. The 20 μl reagents were administered onto the exposed septal mucosal surface, and the venous diameters of nasal mucosa were observed. Results The SNP-induced venodilatation of septal mucosa was markedly and significantly increased in the antigen-challenged rats. The SNP-induced venodilatation was significantly inhibited by pretreatment with either tetraethylammonium [TEA; a large-conductance Ca 2+ activated-K + (K Ca) and voltage dependent K + (Kv) channel inhibitor] or glibenclamide [an ATP sensitive K + (K ATP) channel inhibitor]. Conclusions These findings suggest that NO-induced venodilatation is augmented in nasal mucosae of challenged rats, and K + channels play an important role in the augmented venous responsiveness to NO in nasal mucosae of repeatedly antigen challenged rats.

Spatial and temporal expression of CCR3 and the common beta chain of the IL-3, IL-5 and GM-CSF receptor in the nasal epithelium and lymphoid tissues in a rat model of allergic rhinitis

Background Allergic rhinitis (AR) and asthma are closely related conditions that often co-exist, and are characterized by a Th2 inflammatory response where eosinophils occupy a predominant role. Strategies aimed at blocking signaling through the CC chemokine receptor 3 (CCR3) and/or the common beta chain of the IL-3, IL-5 and GM-CSF receptor (βc) efficiently reduced eosinophilic inflammation in both animal models and in asthmatic patients. This study was therefore aimed at characterizing the spatio-temporal expression pattern of βc and CCR3 using a rat model of AR. Methods Sensitized rats were challenged with ovalbumin and sacrificed at 2 h, 8 h, 16 h or 24 h post-challenge. Nasal tissues were microdissected and used for mRNA quantification by QPCR, while histological evaluation determined the presence of eosinophils and mucosubstances. Results Allergen-induced recruitment of eosinophils in the distal septum and turbinates was maximal at 8 h post-challenge, and was correlated with 2–4-fold increase in CCR3 and βc mRNA. Recruitment of eosinophils was also accompanied by upregulated IL-5, IL-4Rα, TNF-α and IFN-γ mRNA at early time-points. In contrast, IL-13 and MUC5AC mRNA, as well as production of mucosubstances were maximal at 24 h. Conclusions βc and CCR3 could play important roles in the modulation of the allergic response, and their inhibition may represent a promising therapeutic approach for AR.

Participation in cysteinyl leukotrienes and thromboxaneA 2 in nasal congestion model in Brown Norway rats

The aim of this study was to investigate the involvement of chemical mediators in a nasal congestion model in Brown Norway (BN) rats. For the above purpose, we studied the effects of pranlukast and zafirlukast (cysteinyl leukotriene (cys-LT) receptor antagonists), seratrodast and ramatroban (thromboxane A 2 (TXA 2) receptor antagonists) on nasal congestion and sneezing induced by toluene 2, 4-diisocyanate (TDI). All of these drugs suppressed the increase of enhanced pause (Penh), the index of nasal congestion, in both early and late phase responses; however, pranlukast, zafirlukast and seratrodast failed to suppress immediate sneezing caused by TDI challenge. These results indicate that cys-LTs and TXA 2 are responsible for the development of both early and late phase nasal congestion. Moreover, these chemical mediators contribute very little to immediate sneezing in a BN rat model of allergic rhinitis.

Effects of cryptoporus polysaccharide on rat allergic rhinitis associated with inhibiting eotaxin mRNA expression

Aqueous extract from the fruiting body of Cryptoporus volvatus has been reported to present anti-tumor, anti-allergy, anti-inflammation and immunomodulatory activities. However, the effect mechanisms of anti-allergy and anti-inflammation are poorly understood. The aim of study is to evaluate whether Cryptoporus polysaccharides (CP) extracted from fruiting body of Cryptoporus volvatus decrease the development of nasal symptoms, airway hyperresponsiveness (AHR) to methacholine (MCh) and the infiltration of eosinophils in nasal mucosa in rat model of allergic rhinitis, and investigate a possible action mechanism of CP by detecting the expression of eotaxin mRNA in nasal mucosa and lung tissues. Rats were immunized with ovalbumin and consecutive topical antigen instillation was performed. Repeated intranasal ovalbumin challenge caused rhinitis symptom, AHR to MCh, eosinophil infiltration and histological alterations into the nasal mucosa and increase of eotaxin mRNA expression in nasal mucosa and lung tissue were examined. Pretreatment with CP 3, 9 and 27 mg kg −1 (ig) decreased the numbers of sneezing 27.4%, 38.4% and 44.3% and nasal rubbing 27.5%, 34.9% and 47.7% comparison with model group, respectively. CP caused a dose-related inhibition of MCh-induced AHR. CP 27 mg kg −1 decreased the expression of eotaxin mRNA in the nasal mucosa by 35%. These results suggest CP can relieve the symptom, eosinophil infiltration and injury of tissue in nasal mucosa and lung tissue and AHR of allergic rhinitis in rats. Its action mechanism may be associated with the decrease of eotaxin mRNA expression.