title: Effect of corticosteroid on lung parenchyma remodeling at an early phase of acute lung injury.
abstract: In vivo (lung resistive and viscoelastic pressures and static elastance) and in vitro (tissue resistance, elastance, and hysteresivity) respiratory mechanics were analyzed 1 and 30 days after saline (control) or paraquat (P [10 and 25 mg/kg intraperitoneally]) injection in rats. Additionally, P10 and P25 were treated with methylprednisolone (2 mg/kg intravenously) at 1 or 6 hours after acute lung injury (ALI) induction. Collagen and elastic fibers were quantified. Lung resistive and viscoelastic pressures and static elastance were higher in P10 and P25 than in the control. Tissue elastance and resistance augmented from control to P10 (1 and 30 days) and P25. Hysteresivity increased in only P25. Methylprednisolone at 1 or 6 hours attenuated in vivo and in vitro mechanical changes in P25, whereas P10 parameters were similar to the control. Collagen increment was dose and time dependent. Elastic fibers increased in P25 and at 30 days in P10. Corticosteroid prevented collagen increment and avoided elastogenesis. In conclusion, methylprednisolone led to a complete maintenance of in vivo and in vitro respiratory mechanics in mild lesion, whereas it minimized the changes in tissue impedance and extracellular matrix in severe ALI. The beneficial effects of the early use of steroids in ALI remained unaltered at Day 30.
authors.affiliation: Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciênces da Saúde, Ilha do Fundão, Brazil.
authors.forename: Patricia R M
authors.initials: PR
authors.lastname: Rocco
authors.forename: Alba B
authors.initials: AB
authors.lastname: Souza
authors.forename: Debora S
authors.initials: DS
authors.lastname: Faffe
authors.forename: Caroline P
authors.initials: CP
authors.lastname: Pássaro
authors.forename: Flávia B
authors.initials: FB
authors.lastname: Santos
authors.forename: Elnara M
authors.initials: EM
authors.lastname: Negri
authors.forename: Januário G M
authors.initials: JG
authors.lastname: Lima
authors.forename: Renata S
authors.initials: RS
authors.lastname: Contador
authors.forename: Vera L
authors.initials: VL
authors.lastname: Capelozzi
authors.forename: Walter A
authors.initials: WA
authors.lastname: Zin
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D004195:Disease Models, Animal; D005260:Female; D007150:Immunohistochemistry; D007275:Injections, Intravenous; D008168:Lung / Q000187:drug effects / Q000473:pathology; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage*; D011336:Probability; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012016:Reference Values; D012128:Respiratory Distress Syndrome / Q000188:drug therapy* / Q000473:pathology*; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics; D016896:Treatment Outcome
chemical_list: D008775:Methylprednisolone