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Behrooz Azizi, Yuming Chen, Alireza Ziaei, Ula V. Jurkunas; Role of P53 in Corneal Endothelial Apoptosis Seen in Fuchs Endothelial Corneal Dystrophy. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6470.
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The purpose of this study was to compare the susceptibility of Fuchs endothelial corneal dystrophy (FECD) and normal corneal endothelial cells (CEC) to oxidative stress and to study the molecular mechanism of oxidative stress-induced apoptosis in FECD-affected endothelium.
Descemet’s membrane along with CEC was dissected from the stroma of normal donors and FECD surgical specimens. Half of each dissected tissue was placed in 500-1000 µM tert-Butyl hydroperoxide (tBHP) for 4 hours at room temperature and the other half was placed in the medium only as a control. The extent of oxidative DNA damage and apoptosis was assessed by immunocytochemistry using anti-8-hydroxydeoxyguanosine (8-OHdG) antibody and TUNEL assay, respectively. P53 levels were assessed by western blot analysis. The change in the extent of DNA damage, apoptosis and p53 synthesis in response to oxidative stress were compared in FECD and normal endothelium.
Baseline p53 expression was 2-fold higher in FECD CEC compared to normal endothelium (n=4, p=0.002). There was higher baseline oxidative DNA damage (8-OHdG) in FECD CEC (n=3, p=0.041). Oxidative DNA damage was increased in both normal and FECD CEC after exposure to tBHP (p=0.031 and 0.022, respectively). The increase in oxidative DNA damage, resulted in 21% increase in TUNEL positive CEC in FECD (p=0.015); however, normal CEC withstood the oxidative insult without any change in TUNEL staining. Total p53 level did not change in response to oxidative stress in either normal or FECD specimens.
FECD corneal endothelial cells were more susceptible to oxidative stress-induced apoptosis than normal endothelium. Even though p53 synthesis is upregulated in FECD, its levels were not affected by oxidative stress applied to specimens ex vivo, pointing to the complex interaction of p53-dependent and independent pathways.
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