After decellularization, thin cut lung slices were incubated in 1mg/ml collagenase Type IV (Worthington, Lakewood, NJ, USA) for 7 days at 37°C on a vibrating plate. Collagenase media was changed every 30 minutes for the first 2 hours, then every hour for the next 2 hours, then every 24 hours thereafter. The colllagenase treated lung was stained with 5-fold excess of rabbit polyclonal anti-elastin antibody (Biorbyt, Cambridge, UK). Both anti-elastin and control conditions were treated with a fluoresceinated goat polyclonal anti-rabbit antibody (Pierce Antibody Products, Rockford, IL, USA). Serial stained sections were examined by flourescence grid confocal microscopy (Lee et al., 2009 (link)), processed in parallel and analyzed using MetaMorph 7,52 (Molecular Devices, Downingtown, PA) intensity applications as previously described (Gibney et al., 2012 (link)).