Abstract
Purpose: :
Mesenchymal stem cells show promising results in cell therapy for many medical fields. We aimed to study their fate when transplanted in the inflammatory corneal environnement: are they able to survive, do they migrate towards the injured tissues, and do they differenciate?
Methods: :
Plastic-adherent, mononucleate cells derived from the bone marrow of New Zealand White rabbits, were transfected with Green Fluorescent Protein (GFP) and expanded in cultures. These MSCs were injected either directly in the stroma, or in the sub-conjunctival space, six hours after the alkali burn of the center of the cornea. Immunohistochemistry and immnunofluorescence were performed one week to four weeks after the transplantation.
Results: :
MSCs were detected by fluorescence microscopy 7 days and 14 days after transplantation, whatever the site of injection was. They were not present in our cut sections after two weeks. After the sub-conjunctival injection, they were mostly localized at the limbus and the peripheral cornea. When transplanted directly in the stroma, they were more dispersed and remained at the site of injection. Fourteen days after transplantation, more than 90% of the MSCs expressed the α- smooth muscle actin marker, like residual keratocytes do. However, MSCs never integrate the epithelial layers and do not express cytokeratins.
Conclusions: :
These initial results suggest that MSCs transfected with GFP can migrate towards the damaged tissue when injected in the sub-conjunctival space and survive for at least two weeks after the transplantation. They engraft to stromal cornea and differenciate rapidly into myofibroblasts. These MSCs are not able to differenciate into epithelial cells in our model.
Keywords: cornea: clinical science • cornea: stroma and keratocytes • regeneration