Madecassoside suppresses migration of fibroblasts from keloids: involvement of p38 kinase and PI3K signaling pathways

Keloid is a specific skin scar that expands beyond the boundaries of the original injury as it heals. The invasive nature of keloid and notable migratory activity of fibroblasts are a hallmark, which distinguishes keloids from other common scars. Madecassoside, a triterpenoid saponin occurring in Centella asiatica herbs, possesses unique pharmacological properties to enhance wound-healing and diminish keloid formation. However, the effects of madecassoside on the formation of keloid scars have been poorly understood. Here, we focused on the potential of madecassoside on the migration of keloid-derived fibroblasts (KFs) and its mechanism. Primary KF, originating from human earlobe keloids, were purified and cultured, and then treated with madecassoside (10, 30, and 100 μM). In both transwell migration assays and scratch-wound-closure assays, KF migration was considerably suppressed by madecassoside pretreatment. Furthermore, KFs treated with madecassoside showed decreased F-actin filaments, as revealed by fluorescein isothiocyanate (FITC)-phalloidin staining and confocal microscopy. By Western blot analysis, madecassoside was shown to remarkably attenuate the phosphorylation of cofilin, p38 MAPK and phosphatidylinositol-3-kinase (PI3K)/AKT signaling, but only exhibited a minor effect on MMP-13 and little effect on ERK1/2 phosphorylation. It was concluded that madecassoside could be of great use in the treatment and/or prevention of hypertrophic scars and keloids.