Histochemistry
To evaluate the presence and distribution of relevant components of the extracellular matrix (ECM), all tissue samples were subjected to histochemical methods. To identify the tissue elastic fibers, samples were stained using Verhoeff histochemical staining method (VHF). To reveal the presence of fibrillar collagens, we used picrosirius red (PSR). Non-fibrillar ECM components were evaluated using alcian blue staining (AB) at pH 2.5 for proteoglycans, and periodic acid–Schiff staining (PAS) for glycoproteins. All these methods were performed following previously published standard histochemical methods (Blanco-Elices et al., 2022; V. S. Carriel et al., 2011; García-García et al., 2021; Sánchez-Porras et al., 2023).