Mesenchymal Stem Cells Have Antifibrotic Effects on Transforming Growth Factor-β1-Stimulated Vocal Fold Fibroblasts

Objectives/Hypothesis: Mesenchymal stem cells (MSCs) hold therapeutic promise for vocal fold scar, yet the precise mechanism(s) underlying tissue level changes remain unclear. We hypothesize that MSCs interact with native fibroblasts to favorably affect healing. Furthermore, we hypothesize that these interactions vary based on MSC source. Methods: Vocal fold fibroblasts (VFFs), adipose-derived stem cells, and hone marrow-derived stem cells (BMSCs) were extracted from Sprague-Dawley rats; and a coculture model was employed culturing VFFs +/- transforming growth factor (TGF-beta 1) (10 ng/mL) +/- MSCs. Monoculture MSCs were also prepared as a control. Both extracellular matrix (ECM) and components of the TGF-beta signaling pathway were analyzed via polymerase chain reaction and western blotting. Results: Significantly decreased TGF-beta 1 mRNA and a-smooth muscle actin protein was observed in VFFs in response to TGF-beta 1 in the coculture with both MSCs (P < 0.05, P < 0.01). BMSCs significantly downregulated collagen I (P < 0.05), collagen Ill (P 0.05), Smad3 (P < 0.01), and TGF-beta 1 receptor I (P < 0.01) mRNA in VFFs. Hyaluronic synthase-1 and 2 increased in cocultured BMSCs when compared with monocultured BMSCs at baseline and in response to TGF-beta 1 (P < 0.01). Conclusion: MSCs had a favorable effect on ECM regulation as well as suppression of TGF-beta 1 signaling in VFF. Bidirectional paracrine signaling was also observed as VFFs altered ECM regulation in MSCs. These data provide insight into the regenerative effects of MSCs and provide a foundation for clinical application.