Immunohistochemistry
Indirect immunohistochemistry was performed for the specific identification of ECM components and cell phenotype. In relation to the ECM fibers, collagens types I, III and IV were determined using this method. In addition, versican (VSC), a hyaluronan-binding proteoglycan which interacts with other ECM components and contributes to control tissue hydration was also studied (Godoy-Guzmán et al., 2018). To identify specific cell phenotypes, immunohistochemical methods were used for the proteins CD73 (marker of stemness and undifferentiation), S100 (marker of chondrogenic and neural crest lineage) and CD34 a well-known marker of blood vessels (García-Martínez et al., 2017; Vela-Romera et al., 2019). All immunohistochemical analyses were carried out using routine methods, and were conducted using the same conditions for all samples. Technical details are summarized in Supplementary Table S1.