Abstract
Purpose :
Non-arteritic anterior ischemic optic neuropathy (NAION) is the most common acute optic neuropathy in patients over 50 years of age and most probably results from flow impairment to the anterior optic nerve, which generates optic nerve (ON) ischemia. We tested the neuroprotective effect of icariin treatment in the rat model of anterior ischemic optic neuropathy (rAION) to rescue retinal ganglion cells (RGCs).
Methods :
Adult male Wistar rats weighing 150-180 g (7- to 8-weeks old) were used in this study. The ONHs of the rats were exposed to an argon laser immediately after an intravenous injection of the photosensitizing agent Rose Bengal. The other normal control eyes received a sham laser. Icariin (5 µM, 3µL) or phosphate-buffered saline (PBS control, 3 μL) was administered immediately by intravitreal injection before or after induction of rAION. We used optical coherence tomography to observe the change of the width of the optic head after icariin treatment to evaluate the presence of optic disc swelling. Visual function was assessed by flash visual evoked potentials (fVEP). RGC density was counted by retrograde labeling with FluoroGold.
Results :
Optical coherence tomography of the optic head showed that the narrower width of optic head in the icariin-treated groups, no matter in group treated prior induction of rAION (221 µm) or in group treated post induction (200 µm), than that in the PBS control group (283 µm). The fVEP analysis showed the higher amplitude of the P1-N2 wave in the icariin-treated groups of prior- and post-induction groups (42±8 μV and 39±13 μV) than the PBS-treated group (17±6 μV). Two weeks after the insult, the RGC densities in the prior- and post-induction of HEP extract-treated groups were significantly higher (1666.72±250.9/mm2 and 1743.17±121.81/mm2) than that of the PBS-treated group (800.14±320.22/mm2).
Conclusions :
The expected findings provide much crucial information about neuroprotective effect of icariin in response to ischemic stress in the rAION model.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.