RESUMO
Allergen challenges induce airway hyperresponsiveness (AHR) and increased airway smooth muscle (ASM) mass in the sensitized rat. Whether the remodeled ASM changes its phenotype is uncertain. We examined, in sensitized Brown Norway rats, the effects of multiple ovalbumin (Ova) challenges on ASM remodeling and phenotype and the role of the epidermal growth factor receptor (EGFR) in these processes. Rats were sensitized with Ova and challenged three times at 5-day intervals with phosphate-buffered saline or Ova and pretreated with the EGFR inhibitor AG-1478 (5 mg/kg) or its vehicle dimethyl sulfoxide. Ova challenges increased ASM mass in all-sized airways and in large airway mRNA expression of smooth muscle myosin heavy chain (sm-MHC), assessed by laser capture. Myosin light chain kinase and the fast myosin isoform SM-B mRNA expressions were not affected. Ova induced AHR to methacholine, and, based on the constant-phase model, this was largely attributable to the small airways and lung derecruitment at 48 h that recovered by 1 wk. The EGFR ligands amphiregulin and heparin-binding epidermal growth factor (HB-EGF) were increased in bronchoalveolar lavage fluid at 48 h after Ova exposure. AG-1478 inhibited AHR and prevented ASM growth. Epithelial gene expression of EGFR, HB-EGF, matrix metalloproteinase (MMP)-9, Gro-α, and transforming growth factor-ß was unaffected by Ova challenges. We conclude that EGFR drives remodeling of ASM, which results from repeated Ova challenge. Furthermore, the latter results in excessive small airway and, to a lesser degree, large airway narrowing to methacholine, and large airway gene expression of contractile protein is conserved.
Assuntos
Brônquios/patologia , Receptores ErbB/genética , Músculo Liso/patologia , Hipersensibilidade Respiratória/patologia , Remodelação das Vias Aéreas/efeitos dos fármacos , Remodelação das Vias Aéreas/imunologia , Alérgenos/imunologia , Alérgenos/farmacologia , Anfirregulina , Animais , Brônquios/efeitos dos fármacos , Brônquios/imunologia , Líquido da Lavagem Broncoalveolar/química , Família de Proteínas EGF , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/imunologia , Regulação da Expressão Gênica/efeitos dos fármacos , Glicoproteínas/genética , Glicoproteínas/imunologia , Fator de Crescimento Semelhante a EGF de Ligação à Heparina , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/imunologia , Masculino , Cloreto de Metacolina/farmacologia , Músculo Liso/efeitos dos fármacos , Músculo Liso/imunologia , Cadeias Pesadas de Miosina/genética , Cadeias Pesadas de Miosina/imunologia , Ovalbumina/imunologia , Ovalbumina/farmacologia , Quinazolinas/farmacologia , Ratos , Hipersensibilidade Respiratória/induzido quimicamente , Hipersensibilidade Respiratória/imunologia , Hipersensibilidade Respiratória/prevenção & controle , Transdução de Sinais/efeitos dos fármacos , Miosinas de Músculo Liso/genética , Miosinas de Músculo Liso/imunologia , Tirfostinas/farmacologiaRESUMO
The electrochemical detection of ibuprofen has been studied on Palladium-Montmorillonite (Mt) modified carbon paste electrode using differential pulse voltammetry. The optimization of the modifier preparation and the instrumental parameters was investigated. The results indicate that ibuprofen oxidation was favored in the presence of Pd-PdO particles. The quantitative determination of ibuprofen was statistically analyzed and validated using HPLC method. The detection and quantification limits, specificity and precision were found to be acceptable. Finally, the developed method was successfully applied for ibuprofen determination in human blood samples.