Abstract
Purpose: :
To examine the expression of the Fas receptor and Fas ligand in the retina following retinal pigment epithelial injury induced by NaIO3.
Methods: :
NaIO3 was injected in Brown-Norway rats (40 mg/kg) and C57Bl6 mice (20 mg/kg) by tail vein or intraperitoneally. Rats and mice were sacrificed at baseline, as well as 3, 7 and 14 days post NaIO3 injection and eyes were processed for histology and immunohistochemistry. Retinas were harvested from rats at 1, 3, or 7 days after NaIO3 injection and quantitative RT-PCR was performed to determine Fas receptor transcript levels.
Results: :
Injection of NaIO3 in rats or mice through tail vein or directly into the intraperitoneal cavity led to significant RPE loss, with a secondary loss of overlying photoreceptors. This was associated with increased Fas receptor immunostaining in the outer nuclear layer of the rat retina. Quantitative RT-PCR demonstrated approximately 2 fold increase in Fas receptor transcript levels in the rats exposed to NaIO3 that correlated with the amount of RPE loss seen on histology. Fas ligand staining was detected in mouse RPE cells at baseline as well as following NaIO3 treatment.
Conclusions: :
NaIO3-mediated RPE loss results in increased levels of Fas receptor mRNA and protein in the retina in rats. We will further test the effect of Fas-receptor inhibition on preventing the secondary loss of photoreceptors that follows NaIO3 exposure.
Keywords: photoreceptors • apoptosis/cell death • retinal pigment epithelium