Processes of blue light-induced damage to retinal pigment epithelial cells lacking phagosomes.
OBJECTIVE
To experimentally clarify the processes of the changes induced by blue light directly on the retinal pigment epithelium (RPE) before the formation of phagosomes or the accumulation of lipofuscin.


METHODS
We developed a new experimental method in which primary cultured cells of very young pigmented rats were exposed to several intensities and durations of blue light (wavelength = 440+/-10 nm).


RESULTS
At 1.0 mW/cm2, the damage was limited to mitochondria. At 2.0 mW/cm2, the cytoplasm exhibited large whorls of membrane or whorled inclusions, which were consistent with autophagic vacuoles. At 4.0 mW/cm2, the RPE cells showed lysis of the cytoplasm and a nucleus that was consistent with necrosis.


CONCLUSIONS
Our results suggested that damage induced by blue light to cultured RPE cells may originate in the mitochondria and end in necrosis. The type of cell death induced in the RPE by blue light seems to be determined mainly by the intensity of the light, but is also related to the duration of exposure.
Pang
J
J
Department of Ophthalmology, Tokyo Medical and Dental University School of Medicine, Japan.
Seko
Y
Y
Tokoro
T
T
D000818:Animals; D002467:Cell Nucleus / Q000528:radiation effects / Q000648:ultrastructure; D002478:Cells, Cultured; D003593:Cytoplasm / Q000528:radiation effects / Q000648:ultrastructure; D008027:Light / Q000009:adverse effects; D008928:Mitochondria / Q000528:radiation effects / Q000648:ultrastructure; D010588:Phagosomes / Q000528:radiation effects* / Q000648:ultrastructure; D010857:Pigment Epithelium of Eye / Q000528:radiation effects* / Q000648:ultrastructure; D051381:Rats; D020318:Rats, Long-Evans