The role of histology in tissue engineering: Significance of complex morphological characterization of decellularized...

Decellularization is a technique of cell removal that prepares vacant extracellular matrices (ECMs), which can be reseeded with patient-specific cells and used in regenerative medicine. Histological methods are vital for protocol standardization and efficacy assessment, which are necessary for preparing such bioscaffolds. Foreskins from male subjects (n=20) aged three to fifteen years were harvested and decellularized using detergent-based and enzyme-based protocols. To acquire a standardized protocol that would provide the optimal balance between effective cell removal and ECM preservation, a total of seven protocols were evaluated using the most basic formalin-fixed paraffin-embedded (FFPE) tissue blocks, which were sectioned and stained with HE, Masson's blue trichrome and orcein. After achieving the optimal result, we further morphologically characterized the scaffolds using scanning electron microscopy (SEM) and immunohistochemical (IHC) detection of fibronectin and collagen IV. Histology proved to be a quick, relatively easy, and cheap method to achieve protocol standardization and assess decellularization efficacy and ECM preservation. Morphological analysis via normal histology, SEM, and IHC showed that both definitive protocols are effective in cell removal but, at the same time, don't compromise the structural integrity of the ECM. Morphological characterization of foreskin-derived bioscaffolds via normal histology, IHC, and SEM is irreplaceable for standardizing decellularization protocols, assessing the efficacy of cell removal, and evaluating ECM preservation.