Fig. 4.

Semiquantitative score of histological findings for immunoreactivity of stain. The intensity of MT staining or COL-1immunostaining and the proportion of PCNA-, VEGF-, or PECAM-1-positive cells were scored as detailed in the Materials and Methods. G1-S, 0.2 mL (1 × 10⁶ cells) UCB-MSCs; G2-P1, 0.2 mL (1 × 10⁶ cells) UCB-MSCs with one injection of 0.2 mL PDRN; G3-P4, 0.2 mL (1 × 10⁶ cells) UCB-MSCs and four injections of 0.2 mL PDRN per week. UCB-MSCs: Human umbilical cord blood-derived mesenchymal stem cell; PDRN: polydeoxyribonucleotide; MTS: Masson’s trichrome stain; COL-1: anti-type 1 collagen antibody; PCNA: proliferating cell nuclear antigen; VEGF: vascular endothelial growth factor; PECAM: platelet endothelial cell adhesion molecule. *p < .016 Kruskal-Wallis test for between-group comparisons, as well as the Mann-Whitney test for comparisons between pairs of groups, when appropriate.