@article {NilhanPA440, author = {Torlak Nilhan and Alkim Yildirim and Egemen Eroglu and Emrah Aydin}, title = {LSC - 2021 - Reversible fetal tracheal occlusion in mice: a novel transuterine method}, volume = {58}, number = {suppl 65}, elocation-id = {PA440}, year = {2021}, doi = {10.1183/13993003.congress-2021.PA440}, publisher = {European Respiratory Society}, abstract = {Aim of the Study: Fetal tracheal occlusion (TO) is an emerging surgical therapy in congenital diaphragmatic hernia (CDH) that improves the fetal lung growth. Different animal models of CDH and TO present advantages and disadvantages regarding ethical issues, cost, surgical difficulty, size, survival rates and available genetic tools. We developed a minimally invasive murine transuterine-reversible TO model, which will be useful in defining how TO impacts lung molecular biology, physiology and cellular processes.Methods: Following approval of IACUC 2018.HADYEK.027, time mated C57BL/6 mice underwent laparotomy at embryonic day 16.5 (E16.5) with transuterine tracheal occlusion performed on 2 fetuses in each uterine horn. The stitch was removed at E17.5 and at E18.5, dams were sacrificed, and fetuses were harvested. All lungs were compared by morphometric and histologic analysis.Main results Successful: TO was confirmed in 61 of 65 TO fetuses. Fifty-seven of them survived to E18.5 (87.7\%), 6 of which had spontaneous vaginal delivery. Fetal weights were comparable. DNA/Protein and DNA/lung weight ratios were elevated while protein/lung weight ratio was lower in TO compared to control.Conclusion: Reversible mice fetal transuterine tracheal occlusion is feasible with comparable outcomes to other current animal models. The increase in the lung weight, lung-to-body weight ratio and the DNA/protein ratio indicate organized lung growth rather than edema or cell hypertrophy.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA440.This abstract was presented at the 2021 ERS International Congress, in session {\textquotedblleft}Prediction of exacerbations in patients with COPD{\textquotedblright}.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/58/suppl_65/PA440}, eprint = {https://erj.ersjournals.com/content}, journal = {European Respiratory Journal} }