Allergic Rats Research Articles

Inhaled Multiwalled Carbon Nanotubes Modulate the Immune Response of Trimellitic Anhydride–induced Chemical Respiratory Allergy in Brown Norway Rats

The interaction between exposure to nanomaterials and existing inflammatory conditions has not been fully established. Multiwalled carbon nanotubes (MWCNT; Nanocyl NC 7000 CAS no. 7782-42-5; count median diameter in atmosphere 61 ± 5 nm) were tested by inhalation in high Immunoglobulin E (IgE)-responding Brown Norway (BN) rats with trimellitic anhydride (TMA)-induced respiratory allergy. The rats were exposed 2 days/week over a 3.5-week period to a low (11 mg/m(3)) or a high (22 mg/m(3)) concentration of MWCNT. Nonallergic animals exposed to MWCNT and unexposed allergic and nonallergic rats served as controls. At the end of the exposure period, the allergic animals were rechallenged with TMA. Histopathological examination of the respiratory tract showed agglomerated/aggregated MWCNT in the lungs and in the lung-draining lymph nodes. Frustrated phagocytosis was observed as incomplete uptake of MWCNT by the alveolar macrophages and clustering of cells around MWCNT. Large MWCNT agglomerates/aggregates were found in granulomas in the allergic rats, suggesting decreased macrophage clearance in allergic rats. In allergic rats, MWCNT exposure decreased serum IgE levels and the number of lymphocytes in bronchoalveolar lavage. In conclusion, MWCNT did not aggravate the acute allergic reaction but modulated the allergy-associated immune response.

Formaldehyde inhalation reduces respiratory mechanics in a rat model with allergic lung inflammation by altering the nitric oxide/cyclooxygenase-derived products relationship

Bronchial hyperresponsiveness is a hallmark of asthma and many factors modulate bronchoconstriction episodes. A potential correlation of formaldehyde (FA) inhalation and asthma has been observed; however, the exact role of FA remains controversial. We investigated the effects of FA inhalation on Ovalbumin (OVA) sensitisation using a parameter of respiratory mechanics. The involvement of nitric oxide (NO) and cyclooxygenase-derived products were also evaluated. The rats were submitted, or not, to FA inhalation (1%, 90 min/day, 3 days) and were OVA-sensitised and challenged 14 days later. Our data showed that previous FA exposure in allergic rats reduced bronchial responsiveness, respiratory resistance (Rrs) and elastance (Ers) to methacholine. FA exposure in allergic rats also increased the iNOS gene expression and reduced COX-1. L-NAME treatment exacerbated the bronchial hyporesponsiveness and did not modify the Ers and Rrs, while Indomethacin partially reversed all of the parameters studied. The L-NAME and Indomethacin treatments reduced leukotriene B₄ levels while they increased thromboxane B₂ and prostaglandin E₂. In conclusion, FA exposure prior to OVA sensitisation reduces the respiratory mechanics and the interaction of NO and PGE₂ may be representing a compensatory mechanism in order to protect the lung from bronchoconstriction effects.

Histological Effects of Inhaled Corticosteroids and ß2‐agonists on Laryngeal Mucosa in an Allergic Rat Model

To constitute an animal model of laryngeal allergy and evaluate the laryngeal effects of inhaled corticosteroids and ß2-agonists on the laryngeal mucosa in an allergic rat model. Prospective randomized. The Experimental Medical Research Institute (DETAE) at Istanbul University. Wistar Albino rats (n = 32) were sensitized with ovalbumin. Unsensitized rats (n = 8) served as controls. The rats were exposed to aerosolized ovalbumin (1%). On days 28 through 42, every 2 days preceeding ovalbumin exposure, rats were further exposed to aerosolized phosphate buffered saline (n = 8), fluticasone propionate (n = 8), salbutamol (n = 8), and combined salbutamol+fluticasone propionate (n = 8). Inflammatory cell infiltration was graded semi-quantitatively. The quantitative data included mast cell count and degranulation. Ultrathin sections were investigated under transmission electron microscope. The simultaneous and pairwise comparison of groups (Kruskal-Wallis) revealed statistically significant difference among groups at supraglottic level (critical P < .05, <.01) and no difference at glottic level. In ovalbumin+phosphate buffered saline exposed rats, the light microscopy of supraglottic mucosa revealed regular epithelium with severe inflammatory cell infiltration and increased mast cell count. Electron microscopy revealed increased mast cell degranulation. Increased inflammatory cell infiltration was detected along with reduced mast cell count among fluticasone propionate treated rats. Mild inflammatory cell infiltration was encountered in combined salbutamol+fluticasone propionate treated rats. This study supported the presence of localized allergic reaction in the supraglottic laryngeal mucosa through the observation of increased mast cell number and degranulation. It was also shown that inhaled corticosteroids increase inflammation whereas combined inhaled corticosteroids and ß2-agonists minimize allergic and inflammatory reactions in supraglottic laryngeal mucosa providing a safer therapeutic option.

Biphasic airway–lung response to anaphylactic shock in Brown Norway rats

Bronchospasm may be part of the response to systemic anaphylaxis in humans. The anaphylactic shock has been characterized in allergic rats, but little data are available on the concurrent changes in airway–lung mechanics. The aim was to describe the respiratory resistance (Rrs) and reactance (Xrs) response to ovalbumin (OVA) induced systemic anaphylaxis in allergic rats. Thirty five anesthetized and mechanically ventilated Brown Norway rats were randomly allocated to OVA (n=20) or vehicle (n=15) sensitization and provocation. Rrs and Xrs were obtained by the forced oscillation technique at 20Hz. Allergic rats showed dramatic and reproducible concurrent Rrs peak and Xrs through within 4min of OVA injection (p<0.0001). Thereafter, Rrs returned to baseline while Xrs remained significantly more negative (p<0.0001). It is concluded that systemic anaphylaxis in allergic rats is associated with severe early acute inhomogeneous bronchoconstriction followed by pulmonary interstitial/small airspace edema. The model may be of interest to assess treatments targeting the associated bronchoconstriction and/or airway vascular leakage.

Herbal Formula-3 inhibits food allergy in rats by stabilizing mast cells through modulating calcium mobilization

The prevalence of food allergy has increased dramatically during the last three decades, but currently there was no effective therapy except avoidance of allergen. This study aimed to investigate the effect of a modified Chinese herbal formula, Formula-3, on mast cell degranulation and the anti-allergic activity in both animal and cell models. With OVA-sensitized food allergic model in Brown-Norway rats, we checked tissue injury in the small intestines by H&E staining. The Th2 cytokine levels and IgE production in serum or supernatant of the intestinal mucosa homogenates were analyzed by ELISA. Meanwhile, rat peritoneal mast cell activation and degranulation were examined by Toluidine Blue Stain and the release of histamine was measured. Furthermore, the regulation of Formula-3 on Ca(2+) mobilization was investigated by probing intracellular Ca(2+) with fluo-4 fluorescence. The direct effect of Formula-3 on mast cell stabilization was also studied in RBL-2H3 cell line. In vivo Formula-3 administration significantly reduced tissue damage in the small intestines of rat and suppressed Th2 cytokine secretion and IgE production. We demonstrated that Formula-3 treatment significantly suppressed FcεR1-mediated mast cell degranulation no matter in OVA-challenged allergic rats or IgE-sensitized RBL-2H3 cell line. Furthermore, Formula-3 significantly decreased Ca(2+) influx through store-operated calcium channels (SOCs) evoked by dinitrophenyl-BSA or thapsigargin in mast cells. Taken together, our data indicate that Formula-3 stabilizes mast cells by suppressing FcεR1-induced Ca(2+) mobilization mainly through inhibiting Ca(2+) entry via SOCs, thus exerting a protective effect against OVA-sensitized food allergy.

Polydatin attenuated food allergyviastore-operated calcium channels in mast cell

To investigate the effect of polydatin (PD), a resveratrol glucoside, on mast cell degranulation and anti-allergic activity. After the rats were orally sensitized with ovalbumin (OVA) for 48 d and underwent PD treatment for 4 d, all the rats were stimulated by 100 mg/mL OVA for 24 h and then sacrificed for the following experiments. The small intestines from all the groups were prepared for morphology examination by hematoxylin and eosin staining. We also used a smooth muscle organ bath to evaluate the motility of the small intestines. The OVA-specific immunoglobulin E (IgE) production and interleukin-4 (IL-4) levels in serum or supernatant of intestinal mucosa homogenates were analyzed by enzyme-linked immunosorbent assay (ELISA). Using toluidine blue stain, the activation and degranulation of isolated rat peritoneal mast cells (RPMCs) were analyzed. Release of histamine from RPMCs was measured by ELISA, and regulation of PD on intracellular Ca(2+) mobilization was investigated by probing intracellular Ca(2+) with fluo-4 fluorescent dye, with the signal recorded and analyzed. We found that intragastric treatment with PD significantly reduced loss of mucosal barrier integrity in the small intestine. However, OVA-sensitization caused significant hyperactivity in the small intestine of allergic rats, which was attenuated by PD administration by 42% (1.26 ± 0.13 g vs OVA 2.18 ± 0.21 g, P < 0.01). PD therapy also inhibited IgE production (3.95 ± 0.53 ng/mL vs OVA 4.53 ± 0.52 ng/mL, P < 0.05) by suppressing the secretion of Th2-type cytokine, IL-4, by 34% (38.58 ± 4.41 pg/mL vs OVA 58.15 ± 6.24 pg/mL, P < 0.01). The ratio of degranulated mast cells, as indicated by vehicles (at least five) around the cells, dramatically increased in the OVA group by 5.5 fold (63.50% ± 15.51% vs phosphate-buffered saline 11.15% ± 8.26%, P < 0.001) and fell by 65% after PD treatment (21.95% ± 4.37% vs OVA 63.50% ± 15.51%, P < 0.001). PD mediated attenuation of mast cell degranulation was further confirmed by decreased histamine levels in both serum (5.98 ± 0.17 vs OVA 6.67 ± 0.12, P < 0.05) and intestinal mucosa homogenates (5.83 ± 0.91 vs OVA 7.35 ± 0.97, P < 0.05). Furthermore, we demonstrated that administration with PD significantly decreased mast cell degranulation due to reduced Ca(2+) influx through store-operated calcium channels (SOCs) (2.35 ± 0.39 vs OVA 3.51 ± 0.38, P < 0.01). Taken together, our data indicate that PD stabilizes mast cells by suppressing intracellular Ca(2+) mobilization, mainly through inhibiting Ca(2+) entry via SOCs, thus exerting a protective role against OVA-sensitized food allergy.

The putative role of ovary removal and progesterone when considering the effect of formaldehyde exposure on lung inflammation induced by ovalbumin

OBJECTIVE:Formaldehyde exposure during the menstrual cycle is known to affect the course of allergic lung inflammation. Because our previous data demonstrated that formaldehyde combined with an ovariectomy reduced allergic lung inflammation, we investigated the putative role of ovary removal and progesterone treatment when considering the effect of formaldehyde on allergic lung inflammation.METHOD:Ovariectomized rats and their matched controls were exposed to formaldehyde (1%, 3 days, 90 min/day) or vehicle, and immediately after exposure, the rats were sensitized to ovalbumin by a subcutaneous route. After 1 week, the rats received a booster by the same route, and after an additional week, the rats were challenged with ovalbumin (1%) by an aerosol route. The leukocyte numbers, interleukin-10 (IL-10) release, myeloperoxidase activity, vascular permeability, ex vivo tracheal reactivity to methacholine and mast cell degranulation were determined 24 h later.RESULTS:Our results showed that previous exposure to formaldehyde in allergic rats decreased lung cell recruitment, tracheal reactivity, myeloperoxidase activity, vascular permeability and mast cell degranulation while increasing IL-10 levels. Ovariectomy only caused an additional reduction in tracheal reactivity without changing the other parameters studied. Progesterone treatment reversed the effects of formaldehyde exposure on ex vivo tracheal reactivity, cell influx into the lungs and mast cell degranulation.CONCLUSION:In conclusion, our study revealed that formaldehyde and ovariectomy downregulated allergic lung inflammation by IL-10 release and mast cell degranulation. Progesterone treatment increased eosinophil recruitment and mast cell degranulation, which in turn may be responsible for tracheal hyperreactivity and allergic lung inflammation.

Long-term amphetamine treatment exacerbates inflammatory lung reaction while decreases airway hyper-responsiveness after allergic stimulus in rats

Asthma is an allergic lung disease can be modulated by drugs that modify the activity of central nervous system (CNS) such as amphetamine (AMPH). AMPH is a highly abused drug that exerts potent effects on behavior and immunity. In this study we investigated the mechanism involved in the effects of long-term AMPH treatment on the increased magnitude of allergic lung response. We evaluated mast cells degranulation, cytokines release, airways responsiveness and, expression of adhesion molecules. Male Wistar rats were treated with AMPH or vehicle (PBS) for 21days and sensitized with ovalbumin (OVA) one week after the first injection of vehicle or AMPH. Fourteen days after the sensitization, the rats were challenged with an OVA aerosol, and 24h later their parameters were analyzed. In allergic rats, the treatment with AMPH exacerbated the lung cell recruitment due increased expression of ICAM-1, PECAM-1 and Mac-1 in granulocytes and macrophages recovered from bronchoalveolar lavage. Elevated levels of IL-4, but decreased levels of IL-10 were also found in samples of lung explants after AMPH treatment. Conversely, the ex-vivo tracheal hyper-responsiveness to methacholine (MCh) was reduced by AMPH treatment, whereas the force contraction of tracheal segments due to in vitro antigen challenge remained unaltered.Our findings suggest that lung inflammation and airway hyper-responsiveness due to OVA challenge are under the distinct control of AMPH during long-term treatment. Our data strongly indicate that AMPH positively modulates allergic lung inflammation via the increase of ICAM-1, PECAM-1, Mac-1 and IL-4. AMPH also abrogates the release of the anti-inflammatory cytokine IL-10.

Mucin 5 Subtype AC Expression and Upregulation in the Nasal Mucosa of Allergic Rhinitis Rats

To elucidate the functions of nuclear factor kappa B (NF-κB) in mucin hypersecretion in allergic rhinitis (AR), we examined the in vivo effects of an NF-κB inhibitor, ammonium pyrrolidine dithiocarbamate (PDTC), on mucin 5 subtype AC (MUC5AC) expression in the nasal mucosa of ovalbumin-sensitized rats. Randomized animal study. Academic medical center. Sprague Dawley rats were randomized into a control group (group A), an AR model group (group B), and an AR model treated with an NF-κB inhibitor (group C). Rats in groups B and C were sensitized systemically and locally by ovalbumin injection and inhalation, whereas group A was treated with normal saline in place of ovalbumin. Pyrrolidine dithiocarbamate (100 mg/kg/d) was given to group C by intraperitoneal injection for 5 days. NF-κBp65, MUC5AC, tumor necrosis factor (TNF)-α, and interleukin (IL)-6 were detected by immunohistochemistry, Western blotting, enzyme-linked immunosorbent assay, or real-time polymerase chain reaction. NF-κB was activated in group B, and significant NF-κBp65 protein was expressed in the nucleus of cells from the nasal mucosa, resulting in upregulated transcription from TNF-α and IL-6 genes, as well as increased contents of TNF-α and IL-6 in the nasal lavage fluids. Pyrrolidine dithiocarbamate inhibited nuclear localization of NF-κBp65 and subsequent downregulation of the transcription and secretion of TNF-α and IL-6. MUC5AC was upregulated in group B but reduced in a time-dependent manner after inhibition of NF-κB activation. NF-κB activation might induce MUC5AC hypersecretion in AR rats by inflammatory cytokines TNF-α and IL-6.

59. Long-term amphetamine treatment increases inflammatory lung reaction and reduces upper airway reactivity after allergic lung inflammation in rats

The purpose of this study was to investigate the repercussions of long-term AMPH treatment on the magnitude of allergic lung inflammation. Male Wistar rats were treated with AMPH or vehicle (PBS) during 21 days and sensitized with ovalbumin (OVA) one week after the first injection of vehicle or AMPH. Fourteen days after the sensitization, the rats were challenged with OVA by aerosol and, 24 h later the parameters were analyzed. In rats treated with AMPH, the OVA challenge exacerbated the increased cell recruitment into the lung and the cellular expression of ICAM-1, PECAM-1 and Mac-1 of cells recovered in bronchoalveolar lavage. Similarly, elevated levels of IL-4 but decreased levels of IL-10 were also found in samples of lung explants from allergic rats after AMPH treatment. Conversely, the ex-vivo tracheal reactivity to methacholine (MCh) was reduced by AMPH treatment, whereas the force contraction of tracheal segments due to in vitro antigen challenge did not alter. Our findings suggest that lung inflammation and upper airway reactivity due to OVA-challenge are under distinct control of AMPH long-term treatment. Our data strongly indicate that AMPH modulates positively the allergic lung inflammation by mechanisms involving the increase of ICAM-1, PECAM-1, Mac-1 and IL-4 and abrogates the release of anti-inflammatory cytokine IL-10.

Calpain inhibition attenuated morphological and molecular changes in skeletal muscle of experimental allergic encephalomyelitis rats

Muscle weakness and atrophy are important manifestations of multiple sclerosis (MS). To investigate the pathophysiological mechanisms of skeletal muscle change in MS, we induced experimental autoimmune encephalomyelitis (EAE) in Lewis male rats and examined morphological and molecular changes in skeletal muscle. We also treated EAE rats with calpepetin, a calpain inhibitor, to examine its beneficial effects on skeletal muscle damage. Morphological changes in muscle tissue of EAE rats included smaller and irregularly shaped muscle fibers and fibrosis. Western blot analysis demonstrated increased calpain:calpastatin ratio, inflammation-related transcription factors (nuclear factor-κB:inhibitor of κB α ratio), and proinflammatory enzymes (cyclooxygenase-2). TUNEL-positive myonuclei in skeletal muscle cells of EAE rats indicated cell death. In addition, markers of apoptotic cell death (Bax:Bcl-2 ratio and caspase-12 protein levels) were elevated. Expression of muscle-specific ubiquitin ligases (muscle atrophy F-box and muscle ring finger protein 1), was upregulated in muscle tissue of EAE-vehicle animals. Both prophylactic and therapeutic treatment with calpeptin partially attenuated muscle changes noted in EAE animals. These results indicate that morphological and molecular changes including apoptotic cell death and protein breakdown develop in skeletal muscle of EAE animals and that these changes can be reversed by calpain inhibition.

A non-allergenic Ole e 1-like protein from birch pollen as a tool to design hypoallergenic vaccine candidates

Recombinant DNA technology offers several approaches to convert allergens into hypoallergenic derivatives that can represent the basis of novel, safer and more effective forms of allergy vaccines. In this context, we used a new strategy for the design of a hypoallergenic derivative of Ole e 1, the main allergen of olive pollen. By screening a cDNA library from birch pollen, the clone BB18, encoding the birch counterpart of Ole e 1, was identified. In this study, BB18 has been produce in Pichia pastoris as a recombinant protein and immunologically characterized. The well-established non-allergenic properties of BB18 were used to generate a genetic variant of Ole e 1, named OB55–58, by site-direct mutagenesis of four residues (E55V56G57Y58) in an IgE/IgG epitope of Ole e 1 by the corresponding ones in BB18 (SDSE). OB55–58 was expressed in P. pastoris, purified to homogeneity and analyzed for IgE-reactivity by means of ELISA using sera from olive pollen allergic patients and rat basophil activation assay. T cell reactivity was assayed in a mouse model of Ole e 1 sensitization. The mutant OB55–58 exhibited an impaired IgE reactivity, but not affected T cell reactivity, compared to wild type rOle e 1. This study emphasizes the usefulness of BB18 as a tool for epitope mapping and for engineering hypoallergenic derivatives of Ole e 1 as vaccine candidates for allergy prevention and treatment.

Enhanced bioavailability and efficiency of curcumin for the treatment of asthma by its formulation in solid lipid nanoparticles

Curcumin has shown considerable pharmacological activity, including anti-inflammatory, but its poor bioavailability and rapid metabolization have limited its application. The purpose of the present study was to formulate curcumin-solid lipid nanoparticles (curcumin-SLNs) to improve its therapeutic efficacy in an ovalbumin (OVA)-induced allergic rat model of asthma. A solvent injection method was used to prepare the curcumin-SLNs. Physiochemical properties of curcumin-SLNs were characterized, and release experiments were performed in vitro. The pharmacokinetics in tissue distribution was studied in mice, and the therapeutic effect of the formulation was evaluated in the model. The prepared formulation showed an average size of 190 nm with a zeta potential value of −20.7 mV and 75% drug entrapment efficiency. X-ray diffraction analysis revealed the amorphous nature of the encapsulated curcumin. The release profile of curcumin-SLNs was an initial burst followed by sustained release. The curcumin concentrations in plasma suspension were significantly higher than those obtained with curcumin alone. Following administration of the curcumin-SLNs, all the tissue concentrations of curcumin increased, especially in lung and liver. In the animal model of asthma, curcumin-SLNs effectively suppressed airway hyperresponsiveness and inflammatory cell infiltration and also significantly inhibited the expression of T-helper-2-type cytokines, such as interleukin-4 and interleukin-13, in bronchoalveolar lavage fluid compared to the asthma group and curcumin-treated group. These observations implied that curcumin-SLNs could be a promising candidate for asthma therapy.

Phosphodiesterases inhibition by Bacilli Calmette-Guérin contributes to decrease asthma in allergic rats.

Phosphodiesterases (PDE) hydrolyse intracellular cAMP and cGMP to inactive 5' monophosphates. Decreased level of cAMP is involved in the pathogenesis of asthma. We and others have shown that phosphodiesterases were upregulated in the lung of allergic rats, and Bacilli Calmette-Guérin (BCG) induced the production of cAMP in vitro. However, it is unclear how BCG's effect asthma and whether it is related to PDEs.In this study, BCG was intraperitoneally injected into male Sprague-Dawley rats sensitized and later the rats were challenged with ovabumin/pertusis. The inflammation in lungs was measured. Airway hyperresponsiveness was determined using MedLab software after intravenous methacholine challenge. Furthermore, cAMP level and adenylate cyclase activity in lungs were analyzed by ELISA, phosphodiesterases activities were analyzed by HPLC, while PDEs mRNA levels in lungs was analyzed by reverse transcription-polymerase chain reaction. Administration of BCG significantly attenuated allergen-induced lung inflammatory response and hyper responsiveness as compared with vehicle treatment. Furthermore, the levels of cAMP in lungs were significantly increased in BCG-treated allergic rats. Interestingly, administration of BCG decreased the activity of cAMP-PDE, but not adenylyl cyclase (AC), activity in lungs of animals. Furthermore, pretreatment with BCG significantly decreased the mRNA levels of PDE4A, 4C, 5 and 8, which were induced in lungs of allergic rats. BCG administration attenuated airway inflammatory response and bronchial hyper responsiveness in rats, which are the most important symptoms in asthma. The decreased PDEs mRNA and inhibited cAMP-PDE activities by BCG contribute, at least in part, prevention of allergen-induced airway inflammation and asthma in rats.

Phosphodiesterases inhibition by Bacilli Calmette-Guérin contributes to decrease asthma in allergic rats.

Phosphodiesterases (PDE) hydrolyse intracellular cAMP and cGMP to inactive 5' monophosphates. Decreased level of cAMP is involved in the pathogenesis of asthma. We and others have shown that phosphodiesterases were upregulated in the lung of allergic rats, and Bacilli Calmette-Guérin (BCG) induced the production of cAMP in vitro. However, it is unclear how BCG's effect asthma and whether it is related to PDEs.In this study, BCG was intraperitoneally injected into male Sprague-Dawley rats sensitized and later the rats were challenged with ovabumin/pertusis. The inflammation in lungs was measured. Airway hyperresponsiveness was determined using MedLab software after intravenous methacholine challenge. Furthermore, cAMP level and adenylate cyclase activity in lungs were analyzed by ELISA, phosphodiesterases activities were analyzed by HPLC, while PDEs mRNA levels in lungs was analyzed by reverse transcription-polymerase chain reaction. Administration of BCG significantly attenuated allergen-induced lung inflammatory response and hyper responsiveness as compared with vehicle treatment. Furthermore, the levels of cAMP in lungs were significantly increased in BCG-treated allergic rats. Interestingly, administration of BCG decreased the activity of cAMP-PDE, but not adenylyl cyclase (AC), activity in lungs of animals. Furthermore, pretreatment with BCG significantly decreased the mRNA levels of PDE4A, 4C, 5 and 8, which were induced in lungs of allergic rats. BCG administration attenuated airway inflammatory response and bronchial hyper responsiveness in rats, which are the most important symptoms in asthma. The decreased PDEs mRNA and inhibited cAMP-PDE activities by BCG contribute, at least in part, prevention of allergen-induced airway inflammation and asthma in rats.

Histamine H&lt;sub&gt;1&lt;/sub&gt; Receptor Gene as an Allergic Diseases-sensitive Gene and Its Impact on Therapeutics for Allergic Diseases

Therapeutics targeting disease-sensitive genes are required for the therapy of multifactorial diseases. There is no clinical report on therapeutics for allergic disease-sensitive genes. We are focusing on the histamine H₁ receptor (H1R) as a sensitive gene. H1R mediates allergy histamine signals. H1R is a rate-limiting molecule of the H1R signal because the signal is increased with elevated receptor expression level. We discovered that the stimulation of H1R induced H1R gene expression through PKCδ activation, resulting in receptor upregulation. The mechanism of H1R gene expression was revealed to play a key role in the receptor expression level in studies using cultured HeLa cells and allergic rhinitis model rats. Preseasonal prophylactic treatment with antihistamines is recommended for the therapy of pollinosis. However, the mechanism of the therapy remains to be elucidated. We demonstrated that repeated pretreatment treatment with antihistamines in the allergic rhinitis model rats resulted not only in improvement of symptoms but also in suppressed elevation of H1R mRNA levels in the nasal mucosa. A clinical trial was then initiated. When symptoms and H1R mRNA levels in the nasal mucosa of pollinosis patients with or without preseasonal prophylactic treatment with antihistamines were examined, both symptoms and high levels of H1R mRNA were significantly improved in treated compared with untreated patients. These results strongly suggest that H1R is an allergic disease-sensitive gene.

Amphetamine modulates cellular recruitment and airway reactivity in a rat model of allergic lung inflammation

Asthma is characterized by pulmonary cellular infiltration, vascular exudation and airway hyperresponsiveness. Several drugs that modify central nervous system (CNS) activity can modulate the course of asthma. Amphetamine (AMPH) is a highly abused drug that presents potent stimulating effects on the CNS and has been shown to induce behavioral, biochemical and immunological effects. The purpose of this study was to investigate the effects of AMPH on pulmonary cellular influx, vascular permeability and airway reactivity. AMPH effects on adhesion molecule expression, IL-10 and IL-4 release and mast cell degranulation were also studied. Male Wistar rats were sensitized with ovalbumin (OVA) plus alum via subcutaneous injection. One week later, the rats received another injection of OVA-alum (booster). Two weeks after this booster, the rats were subjected to AMPH treatment 12 h prior to the OVA airway challenge. In rats treated with AMPH, the OVA challenge reduced cell recruitment into the lung, the vascular permeability and the cellular expression of ICAM-1 and Mac-1. Additionally, elevated levels of IL-10 and IL-4 were found in samples of lung explants from allergic rats. AMPH treatment, in comparison, increased IL-10 levels but reduced those of IL-4 in the lung explants. Moreover, the tracheal responsiveness to methacholine (MCh), as well as to an in vitro OVA challenge, was reduced by AMPH treatment, and levels of PCA titers were not modified by the drug. Our findings suggest that single AMPH treatment down-regulates several parameters of lung inflammation, such as cellular migration, vascular permeability and tracheal responsiveness. These results also indicate that AMPH actions on allergic lung inflammation include endothelium–leukocyte interaction mechanisms, cytokine release and mast cell degranulation.

The effects of antisense interleukin-4 gene transferred by recombinant adeno-associated virus vector on the airway remodeling in allergic rats

Background: Th2-derived cytokines, including interleukin-4 (IL-4), are considered to play an important role in the development of airway remodeling of asthma. Objectives: Our previous study has demonstrated that a recombinant adeno-associated virus containing antisense against IL-4 gene (rAAV-asIL4) vector could significantly suppress the expression of IL-4 protein and airway inflammation in the rat models of allergic asthma. In this study, we applied the rAAV-asIL4 vector to allergic rats to investigate the effects of anti-IL4 therapy on airway remodeling in allergic asthma. Methods: rAAV-asIL4 was used to infect the ovalbumin (OVA)-sensitized and challenged rats by tail-vein injection. IL-4 protein in bronchoalveolar lavage fluid (BALF) was detected by enzyme-linked immunosorbent assay. The number of eosinophils in BALF was counted. Transforming growth factor-beta1 (TGF-beta1) and TGF-beta2-positive cells in the peribronchial space were detected by immunohistochemical staining, and collagen deposition beneath the basement membrane was detected by Sirius red stain. The lung tissues were collected for histologic analysis of total bronchial wall area (WAt) and airway smooth muscle area (WAm). Results: rAAV-asIL4 significantly decreased IL-4 protein in BALF of OVA-sensitized and challenged rats. The number of eosinophils in BALF, the TGF-beta1 and TGF-beta2-positive cells in the peribronchial space were also suppressed. Moreover, the rAAV-asIL4 treatment inhibited the area of Sirius red staining in airways and the increase in WAt and WAm. Conclusion: These results suggest that rAAV-asIL4 may attenuate the airway remodeling process relevant to the inhibition of airway inflammation. This study provides elementary evidence for the potential utility of rAAV-asIL4 as an approach to gene therapy for asthmatic airway remodeling.

Recombinant Adeno-Associated Virus Vector-Mediated Delivery of Antisense Interleukin-5 Gene Attenuates Airway Remodeling in Allergic Rats

Background: Increasing evidence indicates that eosinophils contribute greatly to airway remodeling in asthma. Since interleukin-5 (IL-5) plays a critical role in the regulation of eosinophils in asthma, anti-IL-5 therapy may be a novel approach to inhibit airway remodeling in asthma. Objectives: In this study, we applied a recombinant adeno-associated virus vector-mediated antisense IL-5 gene delivery (rAAV-ASIL-5) system to investigate its effect on airway remodeling in ovalbumin (OVA)-sensitized and -challenged rats. Methods: rAAV-ASIL-5 was used to infect OVA-sensitized and -challenged rats. IL-5 protein in bronchoalveolar lavage fluid (BALF) was detected by ELISA. The eosinophils in BALF were counted. Transforming growth factor (TGF)-β1- and TGF-β2-positive cells in the peribronchial space were detected by immunohistochemical staining. Lung tissue was collected for Sirius red staining and histological analysis. Results: rAAV-ASIL-5 significantly decreased the level of IL-5 protein, the number of eosinophils in BALF and the numbers of TGF-β1- and TGF-β2-positive cells in the peribronchial space. The area of Sirius red staining in airways was also decreased. Moreover, the rAAV-ASIL-5 treatment inhibited the increase in total bronchial wall area and airway smooth muscle area. Conclusion: These results suggest that rAAV-ASIL-5-based gene therapy could be used to inhibit airway remodeling in allergic rats.

Female sex hormones mediate the allergic lung reaction by regulating the release of inflammatory mediators and the expression of lung E-selectin in rats

BackgroundFluctuations of estradiol and progesterone levels caused by the menstrual cycle worsen asthma symptoms. Conflicting data are reported in literature regarding pro and anti-inflammatory properties of estradiol and progesterone.MethodsFemale Wistar rats were ovalbumin (OVA) sensitized 1 day after resection of the ovaries (OVx). Control group consisted of sensitized-rats with intact ovaries (Sham-OVx). Allergic challenge was performed by aerosol (OVA 1%, 15 min) two weeks later. Twenty four hours after challenge, BAL, bone marrow and total blood cells were counted. Lung tissues were used as explants, for expontaneous cytokine secretion in vitro or for immunostaining of E-selectin.ResultsWe observed an exacerbated cell recruitment into the lungs of OVx rats, reduced blood leukocytes counting and increased the number of bone marrow cells. Estradiol-treated OVx allergic rats reduced, and those treated with progesterone increased, respectively, the number of cells in the BAL and bone marrow. Lungs of OVx allergic rats significantly increased the E-selectin expression, an effect prevented by estradiol but not by progesterone treatment. Systemically, estradiol treatment increased the number of peripheral blood leukocytes in OVx allergic rats when compared to non treated-OVx allergic rats. Cultured-BAL cells of OVx allergic rats released elevated amounts of LTB4 and nitrites while bone marrow cells increased the release of TNF-α and nitrites. Estradiol treatment of OVx allergic rats was associated with a decreased release of TNF-α, IL-10, LTB4 and nitrites by bone marrow cells incubates. In contrast, estradiol caused an increase in IL-10 and NO release by cultured-BAL cells. Progesterone significantly increased TNF- α by cultured BAL cells and bone marrow cells.ConclusionsData presented here suggest that upon hormonal oscillations the immune sensitization might trigger an allergic lung inflammation whose phenotype is under control of estradiol. Our data could contribute to the understanding of the protective role of estradiol in some cases of asthma symptoms in fertile ans post-menopausal women clinically observed.