Mouse strain dependence of lung tissue mechanics: role of specific extracellular matrix composition.

This study analyses the differences between C57BL/10 and BALB/c mice in lung tissue micromechanical behaviour and whether specific histological characteristics are related to the mechanical profile. C57BL/10 and BALB/c subpleural lung strips were submitted to multisinusoidal deformation with frequencies ranging between 0.2 and 3.1 Hz. Tissue resistance (R), elastance (E), and hysteresivity (eta) at each frequency were determined before and 30s, 1, 2, and 3 min after acetylcholine (ACh) treatment. BALB/c mice showed higher E and R, at baseline, as well as greater amount of collagen and elastic fibres, and alpha-actin than C57BL/10 mice. However, E, R, and eta augmented with the same magnitude after ACh treatment in both strains. Baseline R was correlated with collagen fibre content and with the volume proportion of alpha-actin, while E was correlated with elastic and collagen fibres, and alpha-actin contents. In conclusion, BALB/c and C57BL/10 mice present distinct tissue mechanical properties that are accompanied by specific extracellular matrix composition and contractile structures.