Estudo dos métodos mecânicos envolvidos na decelularização do coração

Abstract

Tissue engineering is often used to construct biological substitutes for damaged organs or tissues. One approach utilizes decellularized native scaffolds for growth of cells is the extracellular matrix, which directly influences the processes of cellular adhesion, proliferation and differentiation. The decellularization process removes the cells from thetissue or organ, while preserving their structure and extracellular matrix components, maintaining geometry and mechanical properties. Different methods can be associated to improve decellularization. The simultaneous use of chemical and mechanical methods can result in more efficient protocols. The objective of this study was to evaluate theperformance of different mechanical methods involved in heart decellularization. The mechanical methods were perfusion and immersion with agitation, with or without electrodes. These methods have been combined with phosphate buffered saline and sodium dodecyl sulfate washes. To evaluate the efficiency of the methods in cells removaland maintaining the integrity of the organ extracellular matrix, microscopic analyzes, quantification of RNA and mechanical tests with latex balloon have been used. The results showed that the perfusion method was the most efficient to heart decellularization, because it was not possible to observe cell nuclei in the extracellular matrix and a great reduction in the RNA was observed. Additionally, the extracellular matrix was preserved.Using immersion with agitation, although reaching a significant reduction in RNA, decellularization occurred only externally. Both treatments altered the mechanical stability of the organ. The addition of electrodes did not affect process efficiency or speed, but they interact with the organic components removed from the organ. During the decellularization process some residues were adhered to the positive electrodes as bloodclots. No other studies were found reporting the use of electrostatic as a method to improve the efficiency of cellular debris removal. Therefore, the use of electrostatics can be promising if will change some test parameters, like the voltage. Perfusion is the most appropriate method to decellularize a whole, dense and complex organ, while immersionwith agitation is better for thinner tissues. Further knowledge about the parameters that influence the decellularization process, chemical or mechanical, is very important to establish a specific protocol for different organs according to their characteristics.