Abstract
Purpose: :
Blue light induces apoptosis in human retinal pigment epithelium (RPE) cells. In this study we examined the effect of illumination of cells with various intensities of blue light and correlated the apoptosis rate with the age (number of passages) of cultured human fetal RPE cells.
Methods: :
Retinal pigment epithelium cells were isolated from human fetal eyes and pure cultures were obtained. Purity of culture was confirmed with cytokeratin assay. Confluent cultures of the first to the sixth passages were exposed to blue light (wavelength 440 nm) in an especially designated incubator with the light intensity between 2 and 5 mW/cm2. The rate of RPE cells apoptosis was analyzed by Annexin V staining using the flow cytometry techniques. RPE cells cultured in the dark served as a control.
Results: :
Blue light induces significant apoptosis in human fetal RPE cells when compared to cells in dark. The rate of apoptosis is related to the intensity of blue light and proportionally increases with the irradiation time. The apoptosis rate is strongly dependent on the passage number and the age (culture time) of the cultured cells for a given passage.
Conclusions: :
Blue light at higher intensity induced proportionally higher apoptosis in cultured HFRPE cells. Aged cultured HFRPE cells exhibit a decreased apoptosis rate.
Keywords: apoptosis/cell death • retinal degenerations: cell biology • flow cytometry