A Novel Precision-cut lung slice stretch model using removable inflation materials.

Mechanical stretch is an important biomechanical stimulus that facilitates tissue development in the respiratory system by programming the epithelium, endothelium, mesenchyme, and immune cells. Lung tissue undergoes stretch-induced lung differentiation under normal prenatal and postnatal development. Furthermore, supraphysiological and aberrant stretch responses are known mechanisms of acute lung injury and ECM disruption. Current in vitro and ex vivo human tissue cyclic mechanical stretch (CMS) models suffer from significant, well-recognized disadvantages and are poorly validated in vivo for longer-term study. Ex vivo precision-cut lung slice (PCLS) models maintain lung tissue architecture and the variety of cell types present in the lung, allowing for a more realistic imitation of the lung microenvironment and the study of cell-cell interactions while under stretch that are not possible in single-cell-type stretch models. 3 Existing agarose-inflated PCLS models are hindered by retention of agarose media in the tissue, which affects material properties and complicates stretch studies, and damaging methods of anchoring the PCLS for stretch. Herein, we present a novel and innovative PCLS system that includes a removable agarose-inflation media and supportive poly(ethylene glycol) (PEG) hydrogel for embedding that can be used to apply CMS to PCLS. We will demonstrate and validate, for the first time, that PCLS can undergo CMS for 24 hours, remain viable, and demonstrate activation of CMS pathways through transcriptomics.