4.8.4. Hematoxylin/Eosin Staining

After depara ffinization, hematoxylin/eosin staining was performed according to manufacturer's instructions (Mayer's hematoxylin, Histolab, Gothenburg, Sweden).

## 4.8.5. Immunohistochemistry (IHC), Immunofluorescence (IF)

After depara ffinization, heat-induced epitope retrieval was performed on a PT Tissue Link system (Histolab). IHC for collagen type IV, periostin, and decorin was performed using the EnVision Dual Link System (K4065, Dako, Glostrup, Denmark) according to manufacturer's instructions, including horse-radish peroxidase (HRP)-coupled secondary antibodies and counterstaining with Mayer's hematoxylin to visualize nuclei. IF for collagen type VI, biglycan, versican, vimentin, and vinculin was performed by incubation with primary antibodies for 1 h and with fluorochrome-coupled secondary antibodies (Thermo Fisher Scientific, 1:200) for 45 min. Sections were mounted with ProLong Gold Antifade Mountant with DAPI (Invitrogen) to visualize nuclei. Unspecific staining of the secondary antibodies was assessed by omitting the primary antibodies (negative control). For antigen retrieval and antibody-specifications see Table 2.


**Table 2.** Antibody specifications.

HIER = heat induced epitope retrieval; HRP = horse-radish peroxidase; A = Alexa Fluor.
