Brain activation following flexible stimulation paradigms of transcorneal electrical stimulation (TES) in a murine model of glaucoma

Transcorneal electrical stimulation (TES) has been shown as a promising treatment for optic neuropathy in DBA/2J glaucoma model mice, however the current knowledge about the most effective application parameters, such as intensity and duration, is limited. In this study, after electrophysiological evaluation and intraocular pressure measurements, a single TES treatment in both eyes was performed and expression of c-Fos in the superior colliculus measured as a response. Groups were formed with 4, 8-month-old mice, 2 male and 2 female, and treated with 1, 10, or 100 μA for 10 or 30 min; a group with no stimulation was used as negative control, and as positive control, a group of mice were injected intraperitoneally with saline solution. As pathophysiology baseline, groups of 3-month-old mice were used to compare the c-Fos expression after injection (positive control), and with no stimulation (negative controls). The 8-month-old mice presented measurable progression of neuropathy compared to young controls. Active c-Fos-labeled cells were detected with TES application as low as 1 μA for 30 min, suggesting that benefits of TES can be harnessed with flexible application paradigms.