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A2923 - Comparison of Decellularization Between Normal and Silicotic Lungs on Lung Function and Extracellular Matrix Components
Author Block: F. F. Cruz1, V. Martins2, V. Capelozzi3, P. L. Silva4, P. R. Rocco5; 1Federal University of Rio De Janeiro, Rio de Janeiro, Brazil, 2Univ of Sao Paulo, sao paulo, Brazil, 3Univ of Sao Paulo, Sao Paulo, Brazil, 4Federal University of Rio De Janeiro, Institute of Biophysics Carlos Chagas Filho, Rio De Janeiro, Brazil, 5Lab of Pulmonary Investigation, Rio De Janeiro, Brazil.
Rationale: Tissue engineering has been proposed as an alternative to transplantation, offering the potential for long-term graft survival without immunosuppressive therapy. Clinical sources for donor scaffolds are limited, with failed-donor and cadaveric lungs regarded as options for ex vivo tissue engineering. However, these lungs may occasionally come from older individuals or those with preexisting lung diseases, such as chronic obstructive pulmonary disease and pulmonary fibrosis. In this study, we comparatively assessed architecture and extracellular matrix (ECM) content in decellularized mouse lungs with silicosis to develop scaffolds for the construction of bioengineered lungs. Methods: Twenty-four C57BL/6 female mice (weight 20-25 g, age 8-12 weeks) were assigned to receive saline or silica particles intratracheally. Fourteen days after administration of saline or silica, lung mechanics were analyzed. After in vivo assessment of lung mechanics, all mice were euthanized and divided into two groups (decellularization or no decellularization). After the final step of the decellularization protocol, the acellular scaffold mechanics were evaluated ex vivo. Lung tissue was harvested from all animals for histological analysis. Results: The pressure-volume (PV) curves of in vivo and ex vivo (non-decellularized) lungs from silicotic animals did not differ. However, PV curves differed significantly between non-decellularized and decellularized lungs. In silicotic lungs, architecture was largely preserved after decellularization. Collagen and elastic fiber content, as well as type I, IV, and V collagen fiber content, were increased in lung tissue regardless of the decellularization process. Immunohistochemistry showed that fibronectin and laminin were largely retained in patterns similar to those seen in non-decellularized lungs. After decellularization, even though total glycosaminoglycans (GAGs) were increased in both non-decellularized and decellularized lungs, no significant changes were observed in chondroitin and dermatan sulfate; however, heparan sulfate levels decreased significantly after the decellularization process. Conclusion: Retention of key ECM components is essential in the decellularization process. Even with reduction of few ECM components, the decellularized scaffolds exhibited preservation of structural and functional ECM proteins. This study also highlights the differences in GAGs observed. Further evaluation of the properties of different GAGs is required to better assess their potential immunogenicity in diseased lungs to be used as scaffolds for tissue engineering.