Development of an encapsulated cultured human retinal pigment epithelial (hRPE) cells in order to safe and atraumatic delivery of the cells into the retinal space is a novel technique. Autologous fibrin sealant may encapsulate the cultured hRPE cells safely and serve as a safe carrier. This study was conducted to investigate the cellular changes of cultured human retinal pigment epithelial (hRPE) cells when treated with different concentrations of fibrin sealant.

hRPE cells (4th to 6th passages) were treated with 10%, 20%, 30%, and 50% fibrin sealant. Cultivated hRPE cells in 20% fetal bovine serum were considered as control. Cell viability was determined by MTT assay and cell morphology was determined by invert microscopy. Treated cells with 20% fibrin sealant were subjected to immunocytochemistry to investigate protein expression of PAX6, Nestin, ZO-1, CHX10, RPE65, and cytokeratin 8/18.

The viability of hRPE cells was significantly different between four concentrations of fibrin sealant on days 1, 3 and 7; viability of cultivated hRPE cells treated with 30% and 50% fibrin sealant was lower than the controls. Viability of the cells in 50% fibrin sealant was half of that in 10% fibrin sealant (35% vs. 70%, respectively). hRPE cells treated with different concentrations of fibrin sealant did not show any significant change in the protein expression of RPE65, nestin, cytokeratin 8/18, and PAX6; but a high expression of ZO-1,CHX-10 was observed following 20% fibrin sealant treatment.

It seems that increasing concentrations of fibrin sealant, as a 3D scaffold, have an inverse effect on the viability of cultivated hRPE cells. Given the MTT and ICC results, it seems that 30% and 50% fibrin sealant create a contact inhibitory effect on cell proliferation and 20% fibrin sealant is the safe concentration for RPE cell encapsulation. High expression of ZO-1 indicated tight junctions between the cells and fibrin.