Neuroprotective effect of transcorneal electrostimulation in a gerbil model of acute intraocular hypertension injury

Abstract

Introduction: Transcorneal electrical stimulation (TcES) has been shown to ameliorate retinal ganglion cells (RGCs) death from a variety of insults in human ocular diseases as well as animal models[1-6]. In acute angle closure glaucoma, treatment is aimed at reducing intraocular pressure (IOP) as quickly as possible in order to prevent further RGC death. However there is currently no treatment available to rescue damaged cells from apoptosis. Here we examine the potential neuroprotective effect of TcES after acute ocular hypertension related injury. Method: To induce acute ocular hypertension injury, IOP was elevated to 76 mmHg for 1 hour by balanced salt solution infusion in the right eye of each gerbil. In the treatment group, TcES was applied to the surgical eye immediately after intraocular hypertension induction and on day 3 post induction. In the control group sham TcES was given to the surgical eye at the same time points. To measure and compare function, flash electroretinogram was performed on day 3. To measure and compare RGCs density, the RGCs were first retrogradely labeled by the fluorogold 7 days after surgery and then counted on a flat mount after the gerbils were sacrificed. Preliminary Results: In the rod pathway, treatment group (n=3) scotopic a-wave and b-wave readings were higher than that in controls (n=5). Furthermore in the cone pathway, photopic a-wave, b-wave together with the photopic negative response was higher in the lower two intensities in the treated group. This was reflected in the histology by a higher RGC density in the treated group. Conclusion: TcES potentially reduces retinal ganglion cell death and preserves retinal function after acute intraocular hypertension injury.