To investigate the phenotype changes of cultured neonatal and adult human retinal pigment epithelial (hRPE) cells when treated with different concentrations of platelet gel.

Neonatal and adult hRPE cells (4th, 5th, and 6th passages) were treated with 10%, 20%, 30% and 50% platelet gel. 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 inverted microscopy. Protein expression of PAX6, Nestin, ZO-1, CHX10, RPE65, and cytokeratin 8/18 was determined by immunocytochemistry.

Viability of cultivated neonatal and adult hRPE cells treated with all concentrations of platelet gel was higher than the Controls. The viability of hRPE cells was significantly different between different concentrations of platelet; lower viability was seen in 10% and higher viability was seen in 50% platelet concentrations. Both neonatal and adult hRPE cells treated with 20% platelet gel demonstrated a high expression of ZO-1; however, they did not show a significant change in the protein expression of Nestin, RPE65, cytokeratin 8/18, and PAX6; however, they also high expression of ZO-1 was shown .

It seems that platelet gel as a 3D substrate has a positive effect on viability of cultivated neonatal and adult hRPE cells; however, 10% and 20% platelet gels seem to be the proper concentrations in terms of low risk of induction of cell death after the lag, log, and plateau phases of cell cycle. High expression of ZO-1 indicated tight junctions between the neonatal and adult RPE cells and the platelet gel.