The Effects of Riluzole and Trolox in Transient Retinal Ischemia

ABSTRACT

PURPOSES: To evaluate the effect of riluzole (water soluble vitamin E, antioxidant) and trolox(glutamatergic neurotransmission antagonist) in transient retinal ischemia. METHODS: The effects of two drugs were investigated in a gerbil model of retinal ischemic injury. Retinal ischemia was induced by clipping both common carotid arteries for 15 minutes. In group I (10 eyes), 10 gerbils received an intraperitoneal injection of the saline, and in group II (10 eyes), riluzole was injected 30 minutes before ischemia and 30 minutes after the end of the ischemic insult and once daily during the recovery period. In group III (10 eyes), trolox was injected and in group IV (10 eyes), riluzole and trolox were injected in a same manner. Electroretinograms were recorded before ischemia and after 1 hour, 2 days, and 7days of reperfusion. Retinas were harvested for histopathology (hematoxyline-eosin staining and Tdt-dUTP terminal nick-end labeling method). RESULTS: Ischemia for 15 minutes caused reduction of a- and b- waves of the electroretinogram. Treatments with riluzole or trolox significantly enhanced the recovery of the reduced a-and b-waves after reperfusion. Combined treatment with riluzole and trolox also enhanced the recovery of the reduced a-and b-waves, but synergistic effect was not observed. Riluzole and trolox also prevented or attenuated ischemia induced cell death (necrosis and apoptosis). CONCLUSIONS: Riluzole and trolox acted in vivo as a potent neuroprotective agents against transient retinal ischemic model. Therefore, riluzole and trolox may be a major drug for use in the protection against retinal ischemic injury.