Abstract
Purpose: :
Fuchs endothelial corneal dystrophy (FECD) is characterized by progressive corneal endothelial damage from apoptosis, likely mediated by oxidative stress. αA- and αB-crystallin and heat shock protein (HSP) 70 are known to protect retina from oxidative stress; however, it is unclear whether such protective mechanisms exist in the corneal endothelial cells (CECs). Herein we studied oxidative stress and crystallins in FECD, using formalin-fixed, paraffin-embedded human samples.
Methods: :
Age-matched, five FECD samples and five pseudophakic bullous keratopathy (PBK) samples with similar pathological findings were used. Five globes with choroidal melanoma served as normal CEC controls. Expression of protective proteins αA-, αB-, β- and γ-crystallin and HSP70 and oxidative stress marker 8-hydroxy-2’-deoxyguanosine (8-OHdG) was studied for immunohistochemical detection. Intensity of immunohistochemical fluorescence was quantified using the Image J image processing software (National Institutes of Health). Results were analyzed using Student’s t-test.
Results: :
Immunohistochemistry showed expression of αA- and αB-crystallin and HSP70 in CECs of globes with choroidal melanoma. Such similar expression was in CECs of FECD, whereas such expressions were minimal or absent in CECs of PBK. β- and γ-crystallin were not detected in any samples. 8-OHdG was detected in CECs of FECD but not in CECs of PBK and choroidal melanoma. The quantification analysis by Image J software showed that the intensity of αA- and αB-crystallin and HSP70 in CECs of FECD was not significantly different compared with that in CECs from globes with choroidal melanoma.
Conclusions: :
The pathological findings in FECD and PBK are similar; but while FECD seems to be associated with oxidative stress, PBK does not. αA- and αB-crystallin and HSP70 were detected in CECs of FCED, suggesting these protective proteins may prevent CECs from oxidative stress in FECD.
Keywords: crystallins • oxidation/oxidative or free radical damage • cornea: endothelium