Functional studies of tissue-engineered human corneal endothelium by corneal endothelial transplantation in New Zealand white rabbits

• AIM: To investigate biological functions of in vitro reconstructed tissue-engineered human corneal endothelia (TE-HCE) by animal corneal endothelium transplantation. • METHODS: TE-HCEs, reconstructed by using untransfected human corneal endothelialcells (HCE cells, labeled with CM-Dil) as seed cells and modified denuded amniotic membrane (mdAM) as scaffold carriers, were used for penetrating corneal endothelium transplantation in New Zealand white rabbits whose corneal endothelium along with Descemet's membrane (DM) was ripped off before transplantation. The corneal transparency was monitored with a slit-lamp biomicroscope, and the CM-Dil label of seed cells was checked with a fluorescent microscope. The morphology of seed cells, formation of cell junctions, integrality of endothelial monolayer and its integrated status to DM were investigated by Alizarin red staining, freeze-section's hematoxylin-eosin (HE) staining and scanning electron microscopy. The ultrastructure of seed cells, DM and corneas were examined by transmission electron microscopy. • RESULTS: Slit-lamp biomicroscopic observation of transplanted eyes showed that the TE-HCEs could maintain corneal transparency of the transplanted New Zealand white rabbits for more than 39 days. Fluorescent observations showed that all the seed cells in the transplanted area had positive CM-Dil labels. Alizarin red staining, freeze-section 's HE staining and scanning electron microscopic detections showed that most of seed cells were in hexagonal morphology, integral endothelial monolayer was reconstructed with tight intercellular junctions, and endothelial monolayer integrated tightly to DM, secreted from seed cells. Transmission electron microscopic examination showed that a continuous endothelial monolayer was reconstructed by transplanted TE-HCE, and the ultrastructures of seed cells, DM and corneas were almost the same with those from control eyes. • CONCLUSION: The cell morphology, status of continuous monolayer, cell junction and ultrastructure of transplanted TE-HCEs are almost the same with those of rabbit corneal endothelia from control eyes. The TE-HCEs, with similar structures and functions to those of rabbit corneal endothelia, have abilities of maintaining long term cornea transparency of New Zealand white rabbits, and may be used promisingly as HCE equivalents for clinical corneal endothelium transplantation.