Aims The purpose of this study is to investigate the impact of mesenchymal stem cell (MSC)-derived soluble factors on the function of keratocytes, with a particular focus on the processes involved in wound healing, including keratocyte activation, migration and proliferation as well as extracellular matrix (ECM) synthesis.

Methods Primary cultured rabbit keratocytes were treated with MSC-conditioned medium (MSC-CM). The paracrine factors released by bone marrow MSCs were examined by ELISA. Time-lapse microscope was used to examine wound closure in vitro. Mouse model of corneal injury was made by epithelial scraping after ethanol injury.

Results MSC-CM significantly increased the wound closure rate of corneal stromal cells in vitro. This enhancement of wound closure by MSC-CM was due to the promotion of cell migration. MSC-CM enhanced keratocyte survival following ethanol injury via inhibiting apoptosis. The expression of ECM component genes in keratocytes was upregulated by MSC-CM. In addition, MSC-CM promoted corneal epithelial wound healing following chemical injury. A number of wound healing mediators were detected in MSC-CM, including vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), hepatocyte growth factor (HGF), transforming growth factor beta 1 (TGFβ1), interleukin 8 (IL8), interleukin 6 (IL6) and monocyte chemoattractant protein 1 (MCP1).

Conclusion MSC secretes certain factors that accelerate corneal re-epithelialisation. The paracrine effects of MSC on corneal wound healing including improvements in cell viability, migration and ECM formation.