Caspase activation in an experimental model of retinal detachment.
OBJECTIVE
To test for apoptotic photoreceptor cell death and caspase activation as a function of time after induction of an experimental retinal detachment.


METHODS
Retinal detachments were created in Brown Norway rats by injecting 10% hyaluronic acid into the subretinal space using a transvitreous approach. Light microscopy and terminal dUTP-biotin nick end-labeling (TUNEL) was performed at 1, 3, 5, and 7 days after detachment to assess for the morphologic features associated with apoptosis. Western blot analysis of retinal protein extracts was performed using antibodies against caspase-3, -7, and -9 and poly-ADP ribose-polymerase (PARP) at 1, 3, and 5 days after detachment.


RESULTS
Light microscopic analysis of detached retinas showed the presence of pyknotic nuclei in the outer nuclear layer and disruption of the normal organization of the photoreceptor outer segments. TUNEL-staining was positive in the outer nuclear layer only in the detached portions of the retina. Western blot analysis confirmed the time-dependent activation of caspase-3, -7, and -9 and PARP in the detached retinas. No morphologic stigmata of apoptosis or caspase activation was detected in attached retinas.


CONCLUSIONS
The apoptotic photoreceptor cell death in experimental retinal detachments is associated with caspase activation.
Zacks
David N
DN
Retina Service, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA. davzacks@umich.edu
Hänninen
Virve
V
Pantcheva
Mina
M
Ezra
Eric
E
Grosskreutz
Cynthia
C
Miller
Joan W
JW
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D053148:Caspase 3; D053179:Caspase 7; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism*; D004195:Disease Models, Animal; D004789:Enzyme Activation; D020287:In Situ Nick-End Labeling; D008297:Male; D020419:Photoreceptor Cells, Vertebrate / Q000201:enzymology* / Q000473:pathology; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D051381:Rats; D011914:Rats, Inbred BN; D012163:Retinal Detachment / Q000201:enzymology* / Q000473:pathology; D013997:Time Factors
D011065:Poly(ADP-ribose) Polymerases; C505410:Casp3 protein, rat; C506435:Casp9 protein, rat; D053148:Caspase 3; D053179:Caspase 7; D053453:Caspase 9; D020169:Caspases