Precision Cut Lung Slices from Bleomycin Challenged Mice – Ex Vivo Model for Testing Novel Therapies for Lung Fibrosis

Introduction: Precision cut lung slices (PCLS) have mostly been used in toxicity and airway contractility studies due to preserved matrix structure, interaction of multiple cell types and size uniformity, while it’s potential for use in disease pathophysiology and drug discovery research is beginning to unveil. Aims and Objectives: The aim of this study was to investigate utility of PCLS prepared from bleomycin challenged mice for testing potential anti-fibrotic therapies. For this purpose, we have tested the effect of ex vivo nintedanib treatment on expression of several fibrotic markers. Methods: C57BL/6 mice were challenged with 30 µg of bleomycin. 14 days after the challenge, PCLS were prepared and incubated in vitro with nintedanib (10 µM to 0.016 µM) for 3 days after which gene and protein expression of fibrotic markers was measured: alpha smooth muscle actin, collagen 1, fibronectin 1, transforming growth factor beta, matrix metalloproteinase 12 and tissue inhibitor of metalloproteinase 1. Results: Gene or protein expression of all measured fibrotic markers, except transforming growth factor beta, was increased in PCLS prepared from bleomycin challenged mice. Nintedanib inhibited alpha smooth muscle actin, collagen 1, fibronectin 1 and matrix metalloproteinase 12 expression. Conclusions: PCLS prepared from bleomycin challenged mice retain increased expression of fibrotic markers during in vitro culture. Nintedanib activity profile in PCLS was comparable to described activity profile in vivo, thus confirming PCLS as potential testing model for discovery of novel anti-fibrotic therapies.