evans-blue and Respiratory-Hypersensitivity

This study was carried out to determine whether hyperventilation of humidified warm air (HWA) induced airway extravasation in ovalbumin (Ova)-sensitized rats. Our results showed: (1) After isocapnic hyperventilation with HWA for 2 min, tracheal temperature (Ttr) was increased to 40.3°C, and the Evans blue contents in major airways and lung tissue were elevated to 651% and 707%, respectively, of that after hyperventilation with humidified room air in Ova-sensitized rats; this striking effect of HWA was absent in control rats. (2) The HWA-induced increase in Evans blue content in sensitized rats was completely prevented by a pretreatment with either L-732138, a selective antagonist of neurokinin type 1 (NK-1) receptor, or formoterol, a selective agonist of β2 adrenoceptor. This study demonstrated that an increase in airway temperature induced protein extravasation in the major airways and lung tissue of sensitized rats, and an activation of the NK-1 receptor by tachykinins released from bronchopulmonary C-fiber nerve endings was primarily responsible.

Topics: Airway Resistance; Analysis of Variance; Animals; Benzamides; Bronchoalveolar Lavage Fluid; Bronchodilator Agents; Evans Blue; Formoterol Fumarate; Hot Temperature; Male; Ovalbumin; Piperidines; Rats; Respiratory Hypersensitivity; Trachea; Tryptophan

Although neurogenic inflammation of the airways via activation of C-fibers is thought to be important in the pathogenesis of asthma, the mechanisms regulating C-fiber activity remain uncertain.. The influence of a cannabinoid receptor agonist, WIN 55,212-2, on C-fiber activation in guinea pig airways was investigated, as was the mechanism by which cannabinoids regulate antigen-induced airway inflammation.. The inhibitory effect of WIN 55,212-2 on antigen-induced plasma extravasation was assessed in guinea pig tracheal tissues by photometric measurement of extravasated Evans blue dye after extraction with formamide.. Pretreatment with WIN 55,212-2 (0.001, 0.01 or 0.1 mg/kg) significantly and dose-dependently reduced tracheal plasma extravasation induced by inhaling a 5% ovalbumin solution for 2 min after pretreatment with a neutral endopeptidedase inhibitor (phosphoramidon at 2.5 mg/kg i.v.). A cannabinoid CB2 receptor antagonist (SR144528) blunted the inhibitory effect of WIN 55,212-2, while a cannabinoid CB1 antagonist (SR141716A) did not. Pretreatment with a neurokinin-1 receptor antagonist (FK888) significantly reduced ovalbumin-induced extravasation of Evans blue dye. Pretreatment with the combination of WIN 55,212-2 and FK888 reduced antigen-induced plasma extravasation more markedly than FK888 alone.. These findings suggest that WIN 55,212-2 inhibits C-fiber activation via the cannabinoid CB2 receptor and thus suppresses antigen-induced inflammation in guinea pig airways.

Topics: Animals; Antigens; Benzoxazines; Camphanes; Cannabinoid Receptor Agonists; Cannabinoid Receptor Antagonists; Capillary Permeability; Dipeptides; Evans Blue; Extravasation of Diagnostic and Therapeutic Materials; Guinea Pigs; Immunization; Indoles; Inflammation; Male; Morpholines; Naphthalenes; Neurokinin-1 Receptor Antagonists; Ovalbumin; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Respiratory Hypersensitivity; Rimonabant; Trachea

Trimellitic anhydride (TMA) is a low molecular weight chemical that may cause occupational asthma in human beings. The objectives of this study were to determine the time course of immune and airway responses to TMA in guinea pigs and to relate the immunologic response to the immediate responses in lung resistance (RL) and plasma exudation induced by allergen challenge.. We studied the effects of time course after sensitization on airway response to TMA in guinea pigs actively sensitized to free TMA, given by intradermal injection (0.1 ml of 0.3% TMA in corn oil). During weeks 1, 2, 3, 5, and 8 after sensitization, anesthetized animals were challenged with TMA conjugated to guinea pig serum albumin (TMA-GPSA), instilled via the airway route. Nonsensitized animals were challenged with the same amount of conjugate 4 weeks after intradermal injection of corn oil only. In the same animal, we measured both RL to monitor airflow obstruction and extravasation of Evans blue dye (20 mg/kg) to quantify airway plasma exudation.. Instillation of TMA-GPSA (0.5%; 50 microliters) into the tracheal lumen caused a significant increase in RL, reaching a maximum at 2.5 minutes after the instillation in the 1-week group (9.0 +/- 5.9 cm H2O/ml/sec) and between 5 and 6 minutes in the 2-, 3-, 5-, and 8-week groups (9.4 +/- 4.8, 12.7 +/- 5.5, 3.7 +/- 1.1, and 1.7 +/- 0.2 cm H2O/ml/sec, respectively). The maximal increase in RL after the challenge in nonsensitized animals was 0.39 +/- 0.05 cm H2O/ml/sec. TMA-GPSA also produced significant extravasation of Evans blue dye at all airway levels in the sensitized groups, and the amount of dye in the peripheral airways was significantly greater than that in the trachea. Furthermore, the level of Evans blue dye in airway tissue increased with the time after sensitization, up to the latest time point tested (8 weeks). Specific IgG1 antibodies to TMA-GPSA demonstrated by ELISA were detected in all animals in the 3-, 5-, and 8-week groups, with maximal levels 5 weeks after sensitization. Specific IgG1 titers to TMA-GPSA significantly correlated with the level of Evans blue dye induced by challenge with TMA-GPSA but not with the increase in RL.. Intradermal sensitization to free TMA induces specific airway allergy for a long period after sensitization. Specific IgG1 antibodies to allergen may influence allergen-induced plasma exudation rather than the airflow obstruction in this animal model of TMA-induced asthma.

Topics: Animals; Blood Pressure; Bronchial Provocation Tests; Capillary Permeability; Enzyme-Linked Immunosorbent Assay; Evans Blue; Guinea Pigs; Immunoglobulin G; Male; Phthalic Anhydrides; Respiratory Hypersensitivity; Time Factors

We studied the role of arachidonic acid metabolites, histamine, and 5-HT in airway responses to trimellitic anhydride (TMA) in actively sensitized guinea pigs. Sensitization was produced by two intradermal injections of free TMA (0.1 ml of 0.3% TMA in corn oil). After 21 to 28 days, guinea pigs were anesthetized and challenged with intratracheal instillation of 0.5% TMA conjugated to guinea pig serum albumin (TMA-GPSA; 50 microliters). Lung resistance (RL) was measured to assess airflow obstruction, and the tissue content of Evans blue dye was measured to assess airway plasma exudation. Before challenge, sensitized animals were pretreated intravenously with inhibitors of different mediators: pyrilamine (antihistamine: 2 mg/kg, indomethacin (cyclooxygenase inhibitor: 10 mg/kg), OKY-046 (thromboxane synthetase inhibitor: 30 mg/kg), ICI-198,615 (leukotriene receptor antagonist: 10(-6) mol/kg), ketanserin (5-HT2 receptor antagonist: 1 mg/kg), or azelastine ("antiallergic agent": 1 mg/kg). Intratracheal instillation of TMA-GPSA induced a slowly progressing increase in RL and produced extravasation of Evans blue dye at all airway levels in sensitized animals. Pyrilamine and azelastine abolished the increase in RL induced by TMA-GPSA until 2.5 min after the challenge. Indomethacin and OKY-046 significantly attenuated the increase in RL 3 min after the challenge. ICI-198,615 and ketanserin did not significantly affect the increase in RL. Extravasation of Evans blue dye induced by TMA-GPSA was decreased by pyrilamine, azelastine and ICI-198,615 in main bronchi and intrapulmonary airways. Indomethacin, OKY-046 and ketanserin did not significantly affect the extravasation of dye into the airway tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Airway Resistance; Animals; Arachidonic Acid; Bronchi; Evans Blue; Exudates and Transudates; Guinea Pigs; Immunization; Indazoles; Indomethacin; Ketanserin; Male; Methacrylates; Permeability; Phthalazines; Phthalic Anhydrides; Pyrilamine; Respiratory Hypersensitivity; SRS-A; Thromboxane-A Synthase

We examined the effect of ONO-1078, a peptide leukotriene antagonist, on antigen-induced airway microvascular leakage in ovalbumin-sensitized guinea pigs. When guinea pigs were pretreated with mepyramine, ovalbumin challenge increased vascular permeability to Evans blue dye in trachea, main bronchi and intrapulmonary airways. Oral administration of ONO-1078 significantly reduced microvascular leakage in intrapulmonary airways at doses more than 3 mg/kg, but not in trachea. Moreover, oral administration of ONO-1078 significantly reduced SRS-A mediated microvascular leakage into all airway tissues and was more effective in intrapulmonary airways at 3 mg/kg. Simultaneously, ONO-1078 also inhibited SRS-A mediated bronchoconstriction. On the other hand, azelastine (10 mg/kg, p.o.), an anti-asthma agent, failed to inhibit microvascular leakage into the airways. These results suggest that peptide leukotrienes may be important mediators of airway microvascular leakage, and that the inhibitory effect of ONO-1078 on antigen-induced airway microvascular leakage in addition to the blockade of bronchoconstriction may have therapeutic implications for bronchial asthma.

Topics: Analysis of Variance; Animals; Bordetella pertussis; Bronchodilator Agents; Capillary Permeability; Chromones; Evans Blue; Extravasation of Diagnostic and Therapeutic Materials; Guinea Pigs; Male; Ovalbumin; Phthalazines; Respiratory Hypersensitivity; Respiratory Physiological Phenomena; Respiratory System; SRS-A