Pigment epithelium derived factor as a neuroprotective agent against ischemic retinal injury

Purpose. Pigment epithelium-derived factor (PEDF) is a protein shown to hav e neurotrophic activity. The purpose of this study was to determine whether PEDF is neuroprotective of retinal neurons that are exposed to transient i schemia-reperfusion. Methods. Transient retinal ischemia was produced by increasing the intraocu lar pressure for 45 min in albino rats eyes. Immediately after reperfusion, PEDF was injected intravitreally into the experimental eyes. Injury was ev aluated morphologically and by measuring the thickness of the inner retinal layers (IRL) and by counting the number of retinal ganglion cells (RGC) in epon embedded sections. Results. Morphologic and morphometric analysis of the thickness of the IRL and the counting of RGC demonstrated that PEDF injected immediately after r eperfusion protected the eyes partially but significantly from the ischemic injury. Conclusions. Intravitreal injection of PEDF even after the ischemia can ame liorate retinal injury. PEDF may be useful in preventing neuronal degenerat ion in the inner retina resulting from ischemia.