Fig. 2
Comparison of the biological functions of EX0, EX10, EX5, EX2.5, and EX1.25. The CCK-8 assay (A) and the western blotting analysis of PCNA (B) were carried out to evaluate the pro-proliferative effect of EX0, EX10, EX5, EX2.5, and EX1.25 on dermal fibroblasts. The effects of the five groups of MSC-Ex on the LPS-induced inflammatory response were assessed. NO (evaluated by nitrite content) synthesis (C) and relative expression of NOS2 (D) in macrophages were tested, with GAPDH as the loading control. Gel contraction assay (E, F) and western blotting analysis (G) were performed to compare the anti-fibrotic effect of the five groups of MSC-Ex on TGF-β1-activated dermal fibroblasts. Higher gel contraction percentages (E) or smaller collagen matrices (F) indicate stronger fibrogenesis. For western blotting analysis (G) of α-SMA (a marker of fibrosis) in TGF-β1-treated dermal fibroblasts, the higher α-SMA expression suggests a higher fibrotic level. In vivo pro-regenerative effects of EX0 and EX1.25 were compared. (H) Photographs of representative wounds from each group on different post-wound days. Scale bar: 2 mm. (I) Quantification of the residual wounds; significance was compared with the control group. (J) Photomicrography of wounds (H&E staining). In the images of the wound tissue on Day 6, the necrotic tissue is on the left side of the blue dashed line, while the regenerated tissue is on the right side of the blue dashed line. Scale bars: 200 μm (left) or 50 μm (right). All statistical analyses were performed by one-way ANOVA with Tukey’s multiple comparison test, *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, ns, not significant. Data are presented as mean ± S.D