Dysfunction of the adult corneal stem cells, located in the limbus, can lead to painful disease of the ocular surface (OSD). Transplantation of allogeneic limbal tissue has a poor prognosis. Ex vivo expanded stem cells from alternative sources such as autologous oral mucosa1 must be transferred to the eye on a scaffold. We hypothesised that nanostructured porous silicon (pSi) could be used as a scaffold to transfer oral mucosal epithelial cells (OMECs) to the eye.
Biocompatibility of pSi in the eye has been confirmed previously in our laboratory.2 Here, we explored the ability of thermally oxidised, aminosilanised and collagen IV coated pSi to support rat OMECs. OMECs harvested from male inbred Sprague-Dawley (ISD) rats were cultured on pSi membranes, characterised for epithelial and stem cell markers, and implanted subconjunctivally into the right eye of female ISD rats. Transplanted cells were detected in samples collected from the ocular surface using FTA paper by a PCR designed to amplify the male-specific sry gene.
The majority of OMECs expressed p63 and CK19 indicating a transient amplifying cell (TAC) phenotype. A population of cells expressed the putative stem cell marker ABCG2. A few differentiated cells expressing CK3 were observed. OMECs on pSi membranes were implanted into rat eyes, without excessive inflammation. The implants remained visible at the operating microscope for 8 weeks. OMECs migrated on to the corneal surface, and were detected by PCR up to 4 weeks post implantation.
In conclusion, pSi membranes supported the growth of a mixed population of rat OMECs including stem cells, TACs and terminally differentiated cells. OMECs migrated across the surface of the cornea, after subconjunctival implantation in rats, and were detected up to 4 weeks post implant. Further work is required to assess the ability to repair damage to the cornea in a rodent model of OSD.