Fig 1: Immunohistochemical (IHC) staining of the umbilical cord (UBC) and permanent periodontal ligament (PDL) tissues (A–P). IHC staining for matrix metallopeptidase 13 (MMP13) in PDL (A, E) and UBC (I, M) tissues. IHC staining for tenascin-N (TNN) in PDL (B, F) and UBC (J, N) tissues. IHC staining for ADAM metallopeptidase domain 22 (ADAM22) in PDL (C, G) and UBC (K, O) tissues. IHC staining for melanoma cell adhesion molecule (MCAM, CD146) in PDL (D, H) and UBC (L, P) tissues. Scale bar: 100 µm in A–D and I–L; 20 µm in E–H and M–P.