Neuroprotective effect of small interfering RNA targeted to caspase-3 on rat retinal ganglion cell loss induced by ischemia and reperfusion injury.
OBJECTIVE
To investigate neuroprotective effects of siRNA targeted to caspase-3 against ischemia and reperfusion (I/R) injury in rat eyes.


METHODS
Retinal ischemia was induced in Wistar rats by increasing the intraocular pressure (IOP) to 110 mmHg for 120 min. To examine the effect of siRNA on rat caspase-3, siRNA was injected into the vitreous cavity 24 h prior to induction of retinal ischemia. Eyes were removed at 2, 7 or 14 days later, and then analyzed for the number of retinal ganglion cells (RGCs), the retinal thickness and the amount of apoptosis of the retinal neural cells (as demonstrated by the TUNEL assay). The amount of caspase-3 mRNA was analyzed by rt-PCR. Differences between groups were evaluated by an unpaired t test.


RESULTS
The numbers of RGCs in the saline and non-silencing siRNA controls were reduced significantly at 2 and 7 days after the I/R injury. RGCs were significantly retained in eyes pretreated with siRNA targeted to caspase-3 as compared to the control eyes at 2 days after the I/R injury. Inner retinal thickness in the control eyes was significantly thinner as compared to the treated eyes at 2 and 7 days after the I/R injury. After siRNA treatment, the amount of caspase-3 mRNA was significantly lower when compared to the saline control group.


CONCLUSIONS
The injection of siRNA targeted to caspase-3 into the vitreous cavity of rat eyes may block caspase-3, and may thus be able to prevent retinal cell death associated with ischemic injury. As inhibition of the apoptosis pathway may provide a neuroprotective effect, examination of new strategies for treating these disorders needs to be undertaken.
Department of Ophthalmology, Saga University Faculty of Medicine, Saga, Japan.
Shinichiro
S
Ishikawa
Akira
A
Hirata
Jo
J
Nakabayashi
Ryo
R
Iwakiri
Satoshi
S
Okinami
D000818:Animals; D053148:Caspase 3 / Q000235:genetics*; D004195:Disease Models, Animal; D015316:Genetic Therapy / Q000379:methods*; D020287:In Situ Nick-End Labeling; D056965:Injections, Intraocular; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D015427:Reperfusion Injury / Q000201:enzymology / Q000473:pathology / Q000628:therapy*; D012164:Retinal Diseases / Q000201:enzymology / Q000473:pathology / Q000628:therapy*; D012165:Retinal Ganglion Cells / Q000201:enzymology / Q000473:pathology; D014822:Vitreous Body
D018696:Neuroprotective Agents; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C505410:Casp3 protein, rat; D053148:Caspase 3