Respiratory Physiology & Neurobiology 165 (2009) 202–207 Contents lists available at ScienceDirect Respiratory Physiology & Neurobiology journal homepage: www.elsevier.com/locate/resphysiol Different strains of mice present distinct lung tissue mechanics and extracellular matrix composition in a model of chronic allergic asthma Mariana A. Antunes a , Soraia C. Abreu a , Nilsa R. Damaceno-Rodrigues b , Edwin R. Parra b , Vera L. Capelozzi b , Mariona Pinart c , Pablo V. Romero c , Patrícia M.R. Silva d , Marco Aurélio Martins d , Patricia R.M. Rocco a,∗ a Laboratory of Pulmonary Investigation, Carlos Chagas Filho Biophysics Institute, Federal University of Rio de Janeiro, Centro de Ciências da Saúde, Ilha do Fundão, 21949-900, Rio de Janeiro, Brazil b Department of Pathology, University of São Paulo, São Paulo, Brazil c Laboratory of Experimental Pneumology, IDIBELL L’Hospitalet, Barcelona, Spain d Laboratory of Inflammation, Oswaldo Cruz Institute, FIOCRUZ-RJ, Brazil article info Article history: Accepted 9 December 2008 Keywords: Tissue mechanics Asthma Lung parenchyma Collagen and elastic fibres Actin abstract The impact of genetic factors on asthma is well recognized but poorly understood. We tested the hypoth- esis that different mouse strains present different lung tissue strip mechanics in a model of chronic allergic asthma and that these mechanical differences may be potentially related to changes of extracel- lular matrix composition and/or contractile elements in lung parenchyma. Oscillatory mechanics were analysed before and after acetylcholine (ACh) in C57BL/10, BALB/c, and A/J mice, subjected or not to oval- bumin sensitization and challenge. In controls, tissue elastance (E) and resistance (R), collagen and elastic fibres’ content, and -actin were higher in A/J compared to BALB/c mice, which, in turn, were more elevated than in C57BL/10. A similar response pattern was observed in ovalbumin-challenged animals irrespective of mouse strain. E and R augmented more in ovalbumin-challenged A/J [E: 22%, R: 18%] than C57BL/10 mice [E: 9.4%, R: 11%] after ACh In conclusion, lung parenchyma remodelled differently yielding distinct in vitro mechanics according to mouse strain. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Asthma is a chronic inflammatory disorder that involves the cen- tral airways as well as peripheral airways and the lung parenchyma (Tulic et al., 2001; Tulic and Hamid, 2003; Sutherland et al., 2004; Xisto et al., 2005). In an attempt to elucidate asthma pathogene- sis and treatment (Ewart et al., 2000; Shinagawa and Kojima, 2003; Wagers et al., 2007), mice are increasingly used in the development of asthma models due to the availability of genetically characterized inbred strains, diversity of immunological tools (Kips et al., 2003; Zosky and Sly, 2007), and easy manipulation. There is evidence that genetic strain variations in mice may exist with regard to in vivo respiratory mechanics and airway hyperre- sponsiveness (Tankersley et al., 1999; Ewart et al., 2000; Held and Uhlig, 2000; Reinhard et al., 2002; Ackerman et al., 2005; Wagers ∗ Corresponding author at: Laboratório de Investigac ¸ ão Pulmonar, Instituto de Biofísica Carlos Chagas Filho - C.C.S., Universidade Federal do Rio de Janeiro, Edifício do Centro de Ciências da Saúde, Bloco G-014, Av. Carlos Chagas Filho, s/n, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, Brazil, CEP: 21941-902. Tel.: +5521 2562 6530; fax: +5521 2280 8193. E-mail address: prmrocco@biof.ufrj.br (P.R.M. Rocco). et al., 2007). Recently, we showed that BALB/c and C57BL/10 mice present distinct tissue mechanical properties that were related to specific extra-cellular fibre composition and amount of contrac- tile structures in their lung parenchyma, suggesting that genetic background determines basal lung tissue function and structural differences between these two strains (Faffe et al., 2006). So far, no study has described mouse strain variations in lung tissue mechan- ics and extracellular matrix components in a model of chronic allergic asthma. The aim of this study was to test the hypothesis that different strains of mice present different in vitro lung mechanical profiles in a model of chronic allergic asthma and that these mechanical differ- ences may be potentially related to changes of specific extracellular matrix composition and/or contractile elements in lung tissue. 2. Methods 2.1. Animal preparation Forty-two mice (25–30 g) were selected (n = 14/each) according to mouse strains (C57BL/10, BALB/c, and A/J). Each mouse strain was randomly divided into two main groups OVA and C groups. In OVA 1569-9048/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.resp.2008.12.003