Abstract
Purpose :
To evaluate the effect of intravitreal injection of zeaxanthin on visual function and survival of retinal ganglion cells (RGC) after acute IOP elevation in mouse.
Methods :
Baseline visual acuity was measured in C57Bl/6 mice using the optokinetic reflex (OKR) (Figure 1). Visual acuity was measured 3 and 7 days after intravitreal injection of 1 µL of 5 µg/µL zeaxanthin in DMSO (n=4). Another group of mice (n=8) received intravitreal injections of 1 µL of 5 µg/µL zeaxanthin in DMSO or 1 µL of DMSO. Visual acuity was assessed at baseline and day 3 after the injection using OKR. IOP elevation was performed on day 4 after the injection (Figure 2). Pupils were dilated with 1% tropicamide and mice were anesthetized with isoflurane. The anterior chamber of the right eye was cannulated with a 33-gauge needle connected to a saline reservoir, which was elevated to maintain an intraocular pressure of 110 mmHg for 60 min. Retinal ischemia was confirmed by whitening of the fundus. A sham procedure performed without elevating the pressure in the contralateral left eye was used as control. Immunohistostaining on flattened retina using brn-3a antibody was performed on day 7 to label RGCs. Images of six 0.18 mm2 areas at one-sixth (central retina), three-sixths (middle retina), and five-sixths (peripheral retina) of each retina were taken using a confocal microscope. Surviving RGCs were counted in a blind manner using ImageJ. The average cell density of each retina was calculated (n = 4).
Results :
Visual acuity was improved after an injection of zeaxanthin intravitreally at day 3 after the injection and returned to baseline levels at day 7 (Figure 1). RGC survival in DMSO and in zeaxanthin group after IOP elevation or sham surgery was compared. RGC count was significantly decreased in the DMSO and the zeaxanthin groups after IOP elevation (p < 0.0001 DMSO sham vs. DMSO IOP, and p < 0.05 zeaxanthin sham vs zeaxanthin IOP, figure 2). However, the zeaxanthin group had greater RGC survival compared to the DMSO group (p < 0.05 zeaxanthin IOP vs. DMSO IOP).
Conclusions :
Zeaxanthin administration in retina leads to an increase in visual acuity due to optical reasons and enhances the survival of RGC after retinal ischemia/reperfusion injury in mouse.
This is a 2020 ARVO Annual Meeting abstract.