Neuroprotective Effect of Transcorneal Electrical Stimulation on Ischemic Damage in the Rat Retina

1. Xiaofen Mo
2. Xin Wang
3. Tiande Shou

Department of Ophthalmology and Vision Science, Eye and ENT Hospital of Fudan University, Shanghai, China

PURPOSE. To investigate whether transcorneal electrical stimulation (TES) has neuroprotective effect on retinal neurons after ischemic insults and the underlying mechamism.

METHODS. Adult female Sprague-Dawley (SD) rats received TES after ocular ischemia induced by elevating the intraocular pressure to 120 mmHg for 60 minutes. Retinal ganglion cells (RGCs) were labeled retrogradely 7 days before ischemia and were quantified 7 and 14 days later. At the same time points, retinal function was assessed by scotopic electroretinography (ERG), combined with retinal histological analysis. The glutamine synthetase (GS) immunoreactivity was compared between ischemic retinas with and without TES under identical confocal laser microscope conditions. The immunohistochemical indications were confirmed by Western blot analysis.

RESULTS. Higher mean density of RGCs was quantified in TES treated retinas compared to retinas without TES on day 7 and 14 after ischemia. Similarly, histological analysis showed TES better preserved the mean thickness of separate retinal layers. ERG studies indicated undergoing TES treatment the b-wave amplitude was also significantly preserved on day 7 after ischemia and recovered robustly on day 14. Immunohistochemical and Western blot analysis b
oth revealed that GS levels remarkably increased after TES and at least lasted for 7 days.

CONCLUSIONS. TES can protect retinal neurons against ischemic insults, related with increasing levels of GS localized in Müller cells. These findings suggest a new approach to the clinical handling of ocular ischemic diseases.