Ryo Iwakiri

Neuroprotective effect of small interfering RNA targeted to caspase-3 on rat retinal ganglion cell loss induced by ischemia and reperfusion injury.

Purpose: 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.

A simulated eye for vitreous surgery using Japanese quail eggs

PurposeWe produced a simulated eye for vitreous surgery training by using Japanese quail eggs, and verified its utility.MethodsWe used a special cutter to cut off the sharp end of a Japanese quail egg, fitted a silicone simulated sclerocorneal cap to the exposed area, and fixed the egg to a base. Trocars were placed in the simulated sclera according to the usual procedure for vitreous surgery, and the yolk and albumen were treated as the vitreous body, and resected by using a vitreous cutter. Membrane peeling was performed on the inner eggshell membrane as if it were the internal limiting membrane.ResultsThe yolk and albumen could be resected with a vitreous cutter in the same way as the vitreous body. The inner eggshell membrane could be visualized under staining with Brilliant Blue G and other stains, enabling peeling to be performed with vitreous forceps in the same way as is normally performed for the human internal limiting membrane.ConclusionThis model can be used for simulating the spatial recognition of the vitreous chamber during vitreous surgery. This model proved useful for initial training in port creation, central vitreous body resection, and membrane manipulation in the macular area.