A great deal of evidence has confirmed that electromagnetic fields can affect the central nervous system and are effective in gene expression as well as development, differentiation, cell proliferation, and apoptosis of embryonic neural cells. This study was conducted to investigate the cellular and molecular changes of cultured human retinal pigment epithelial (hRPE) cells when treated with pulsed electromagnetic fields.

Cultured neonatal hRPE cells with confluency of 60% were exposed to pulsed electromagnetic field of 1 mT intensity and 50 Hz frequency 8 hours daily for 3 days. In addition to cell proliferation and cell death assays, immunocytochemistry for RPE65, Pax6, Nestin and cytokeratin 8/18 proteins were performed. Extracted RNAs were subjected to real-time PCR for Nestin, Pax6, RPE65, and α-SMA.

Treated hRPE cells did not demonstrate significant change in terms of cell proliferation and cell death. Protein expressions of Pax6, Nestin, and cytokeratin 8/18 were decreased in treated cells compared to controls and remained unchanged for RPE65. Gene expressions of Nestin, RPE65 and Pax6 were decreased in treated cells as compared to controls (P value < 0.05). Gene expression of α-SMA did not reveal a significant change.

Our study demonstrated that both gene and protein expressions of retinal progenitor cells markers were decreased in cultivated hRPE cells after exposure to safe dose of pulsed electromagnetic field. Decreased protein expression of cytokeratin 8/18 and decreased gene expression of RPE65 may be indicative of either transdifferentiation or senescence of RPE cells. The results of this study are suggestive of a possible role of safe dose of short term pulsed electromagnetic fields on the development of age related macular degeneration. These electromagnetic fields are produced by all electronic and high tech devices that are widely used in the world.