Abstract
Purpose: :
To investigate whether G-CSF protects photoreceptors from light-induced cell death.
Methods: :
BALB/c mice were exposured to 5 klux white fluorescent light for 2 hours. They were injected with G-CSF or vehicle before the light exposure and following consecutive 4 days. Morphologic and electrophysiological examinations were performed 1 week later. To examine the effect of leukocyte, mice irradiated with 6.5 Gy of gamma ray underwent same procedure. The expression of G-CSF and G-CSF receptor in retina was analyzed with quantitative RT-PCR.
Results: :
Outer nuclear layer thickness was preserved in G-CSF treated mice( measured at 300µm superior from optic disc,G-CSF:14.9+6.3µm vs control:6.7+2.5µm) and electroretinogram also confirmed the preservation of wave amplitudes (scotopic a-wave G-CSF:97.7+48.0µV vs control:14.4+21.9µV, scotopic b-wave G-CSF:298.1±145.3µV vs control:33.2±50.1µV). The effect was not lost even with total depletion of leukocytes by irradiation. G-CSF and G-CSF receptor were found in retinal cells and upregulated with light exposure. (2 hours after light exposure, 2.2 folds)
Conclusions: :
G-CSF protects photoreceptor against light-induced damage via G-CSF receptor expressed on retinal cells. The findings can lead to the novel treatment strategy for retinitis pigmentosa and other retinal diseases.
Keywords: apoptosis/cell death • photoreceptors