title: Inactivation of capsaicin-sensitive nerves reduces pulmonary remodeling in guinea pigs with chronic allergic pulmonary inflammation.
abstract: Pulmonary remodeling is an important feature of asthma physiopathology that can contribute to irreversible changes in lung function. Although neurokinins influence lung inflammation, their exact role in the extracellular matrix (ECM) remodeling remains to be determined. Our objective was to investigate whether inactivation of capsaicin-sensitive nerves modulates pulmonary ECM remodeling in animals with chronic lung inflammation. After 14 days of capsaicin (50 mg/kg, sc) or vehicle administration, male Hartley guinea pigs weighing 250-300 g were submitted to seven inhalations of increasing doses of ovalbumin (1, 2.5, and 5 mg/mL) or saline for 4 weeks. Seventy-two hours after the seventh inhalation, animals were anesthetized and mechanically ventilated and the lung mechanics and collagen and elastic fiber content in the airways, vessels and lung parenchyma were evaluated. Ovalbumin-exposed animals presented increasing collagen and elastic fiber content, respectively, in the airways (9.2 ± 0.9; 13.8 ± 1.2), vessels (19.8 ± 0.8; 13.4 ± 0.5) and lung parenchyma (9.2 ± 0.9; 13.8 ± 1.2) compared to control (P < 0.05). Capsaicin treatment reduced collagen and elastic fibers, respectively, in airways (1.7 ± 1.1; 7.9 ± 1.5), vessels (2.8 ± 1.1; 4.4 ± 1.1) and lung tissue (2.8 ± 1.1; 4.4 ± 1.1) of ovalbumin-exposed animals (P < 0.05). These findings were positively correlated with lung mechanical responses to antigenic challenge (P < 0.05). In conclusion, inactivation of capsaicin-sensitive nerve fibers reduces pulmonary remodeling, particularly collagen and elastic fibers, which contributes to the attenuation of pulmonary functional parameters.
authors.affiliation: Departamento de Ciências Biológicas, Universidade Federal de São Paulo, Diadema, SP, Brazil. cmaximoprado@gmail.com
authors.forename: C M
authors.initials: CM
authors.lastname: Prado
authors.forename: G Z
authors.initials: GZ
authors.lastname: da Rocha
authors.forename: E A
authors.initials: EA
authors.lastname: Leick-Maldonado
authors.forename: C M
authors.initials: CM
authors.lastname: Starling
authors.forename: V L
authors.initials: VL
authors.lastname: Capelozzi
authors.forename: M A
authors.initials: MA
authors.lastname: Martins
authors.forename: I F L C
authors.initials: IF
authors.lastname: Tibério
mesh_terms: D056151:Airway Remodeling / Q000187:drug effects*; D000818:Animals; D001249:Asthma / Q000378:metabolism / Q000473:pathology*; D002211:Capsaicin / Q000494:pharmacology*; D002908:Chronic Disease; D003094:Collagen / Q000187:drug effects* / Q000378:metabolism; D003714:Denervation; D004547:Elastic Tissue / Q000187:drug effects* / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects* / Q000378:metabolism; D006168:Guinea Pigs; D008168:Lung / Q000187:drug effects* / Q000473:pathology; D008297:Male; D010047:Ovalbumin
chemical_list: D010047:Ovalbumin; D003094:Collagen; D002211:Capsaicin