OCT evaluation of neuroprotective effects of tafluprost on retinal injury after intravitreal injection of endothelin-1 in the rat eye.

PURPOSE To determine whether optical coherence tomography (OCT) is a useful technique to monitor retinal damage and to evaluate the neuroprotective effect of topical tafluprost in a rat model of intravitreal endothelin-1 (ET-1) injection. METHODS A single intravitreal injection of ET-1 (0.2-200 pmol/eye) was performed in one eye. Optical coherence tomography imaging was performed until 2 weeks after ET-1 injection. Subsequently, an intravitreal injection of ET-1 (20 pmol/eye) was performed in one eye of each rat, which was followed by topical instillation of tafluprost or saline once daily for 4 weeks. Optical coherence tomography imaging was performed until 4 weeks after ET-1 injection. After the last OCT session, retinal ganglion cells (RGCs) were retrogradely labeled with Fluorogold. RESULTS Endothelin-1 at doses of 20 to 200 pmol/eye caused a significant decrease in inner retinal thickness, whereas ET-1 at doses of 0.2 to 5 pmol/eye did not. The inner retinal thickness at 2 weeks postinjection was strongly correlated with Fluorogold-labeled RGC counts in the central retina (r = 0.92, P < 0.001). The inner retina of eyes treated with tafluprost was significantly thicker than eyes treated with saline at 1 and 2 weeks (P = 0.038 and P = 0.045, respectively). Fluorogold-labeled RGC counts in the central retina of eyes treated with tafluprost were significantly greater than in eyes treated with saline (P = 0.03). CONCLUSIONS Optical coherence tomography is useful for monitoring inner retinal damage in a rat model of intravitreal ET-1 injection. Daily topical administration of tafluprost may be protective against ET-1-induced retinal injury in the rat.