Human mesenchymal stem cells-conditioned medium improves diabetic wound healing mainly through modulating fibroblast behaviors

Fibroblast plays a key role in wound healing, and the advantages of mesenchymal stem cells (MSC) secretome in wound healing have previously been reported. In the present study, we investigated the impact of human bone marrow MSC-conditioned media (CM) on skin wound healing in diabetic rats and found that some improvements occurred mainly through fibroblast functions. Then, we scrutinized the impact of MSC-CM treatment on fibroblast cellular behavior by culturing human dermal fibroblasts (HDFs) in a high-glucose (HG) medium, as an in vitro diabetic model. In vivo findings revealed significant improvements in some healing kinetics of diabetic wound which received MSC-CM. Particularly, MSC-CM-treated diabetic wounds reached considerably higher percentages of wound closure. Also, the granulation tissue of these wound had less pronounced inflammatory response, better tissue remodeling, and more vascularization compared with non-treated diabetic ones. Gene expression analyses indicated that MSC-CM treatment leads to upregulation of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) genes. In addition, a significantly higher cell viability/proliferation, migration, and bFGF gene expression were observed when MSC-CM was used to treat HDFs in HG culture media. Based on these findings, it is suggested that MSC-CM could promote wound repair and skin regeneration, in some major processes, via improvement of cellular behaviors of fibroblasts in the diabetic microenvironment. The beneficial advantages of mesenchymal stem cells-conditioned media on fibroblast cellular behaviors and wound healing may lead to establish a novel approach as an alternative therapeutic procedure to cure chronic wounds in diabetic conditions.