Dexamethasone reduces bronchial wall remodeling during pulmonary migration of Strongyloides venezuelensis larvae in rats.
Strongyloidiasis is an intestinal parasitosis with an obligatory pulmonary cycle. A Th2-type immune response is induced and amplifies the cellular response through the secretion of inflammatory mediators. Although this response has been described as being similar to asthma, airway remodeling during pulmonary migration of larvae has not yet been established. The aim of this study was to identify the occurrence of airway remodeling during Strongyloides venezuelensis (S. v.) infection and to determine the ability of dexamethasone treatment to interfere with the mechanisms involved in this process. Rats were inoculated with 9,000 S. v. larvae, treated with dexamethasone (2 mg/kg) and killed at 1, 3, 5, 7, 14 and 21 days. Morphological and morphometric analyzes with routine stains and immunohistochemistry were conducted, and some inflammatory mediators were evaluated using ELISA. Goblet cell hyperplasia and increased bronchiolar thickness, characterized by edema, neovascularization, inflammatory infiltrate, collagen deposition and enlargement of the smooth muscle cell layer were observed. VEGF, IL1-β and IL-4 levels were elevated throughout the course of the infection. The morphological findings and the immunomodulatory response to the infection were drastically reduced in dexamethasone-treated rats. The pulmonary migration of S. venezuelensis larvae produced a transitory, but significant amount of airway remodeling with a slight residual bronchiolar fibrosis. The exact mechanisms involved in this process require further study.
Department of Pathology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil. cristefe@usp.br
Cristiane
C
Tefé-Silva
Cristina T
CT
Beneli
Mara R
MR
Celes
Eleuza R
ER
Machado
Marlene T
MT
Ueta
Carlos A
CA
Sorgi
Elaine M
EM
Floriano
Lúcia H
LH
Faccioli
Simone G
SG
Ramos
D056151:Airway Remodeling / Q000187:drug effects*; D000818:Animals; D001980:Bronchi / Q000187:drug effects* / Q000503:physiopathology; D003907:Dexamethasone / Q000494:pharmacology*; D053583:Interleukin-1beta / Q000097:blood; D015847:Interleukin-4 / Q000097:blood; D007814:Larva / Q000254:growth & development / Q000472:pathogenicity; D008168:Lung / Q000469:parasitology*; D008297:Male; D032389:Myocytes, Smooth Muscle; D051381:Rats; D017208:Rats, Wistar; D013321:Strongyloides / Q000254:growth & development / Q000472:pathogenicity*; D013322:Strongyloidiasis / Q000469:parasitology / Q000503:physiopathology*; D014132:Trachea / Q000187:drug effects* / Q000503:physiopathology; D042461:Vascular Endothelial Growth Factor A / Q000097:blood
D053583:Interleukin-1beta; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D015847:Interleukin-4; D003907:Dexamethasone