Figure 4

Ad-MSCs-SF and D-Ad-MSCs-SF stimulate HUVECs migration by using the scratch test assay. HUVECs, DFs and KCs were cultured in Ibidi Culture-Insert to confluence. Thereafter, the Ibidi Culture-Insert was removed and cells were co-cultured with control medium or in the presence of SF, Ad-MSCs-SF or D-Ad-MSCs-SF patches located in transwells (a scheme of the assay is also reported in Additional file 1: Figure S5). HUVECs (A), DFs (B) and KCs (C) migrated into the inter-space were counted at different intervals of time under microscopy at 20× magnifications in five random fields. Bars in the figures are the means ± SD of three independent experiments. Each migration test was run in triplicate. *P <0.05; **P <0.01 versus untreated SF patches. During migration of HUVECs (D), DFs (E) and KCs (F) photographs were taken to establish the time necessary for the cells to complete the coverage of scratch area. Note that HUVECs stimulated by D-Ad-MSCs-SF patches were the most efficient in completing the coverage of the scratch area that was completed in 48 hours. In the figure, the dotted white lines indicate the margin of the scratch. Ad-MSCs-SF, silk fibroin patch cellularized with human adipose-derived mesenchymal stromal cells; D-Ad-MSCs-SF, silk fibroin patch after human adipose-derived mesenchymal stromal cells removal (decellularization); DFs, dermal fibroblasts; HUVECs, human umbilical vein endothelial cells; KCs, keratinocytes; SF, silk fibroin.