Transcorneal electrical stimulation induced antidepressant-like effects in S334ter-line-3 rat model of retinal degeneration

Abstract

Introduction: Retinitis pigmentosa (RP) is a retinal degeneration disease and many studies have found that depression is highly associated with patients of RP. Although transcorneal electrical stimulation (TES) has been shown to effectively treat retinal neuropathies, no studies were conducted to investigate the TES-evoked responses in depressive-like behaviours. Materials and Methods: The 12-week-old male S334ter-line-3 rat model of RP and control animals received 1 week of TES with a range of stimulation parameters (100, 200, and 500 μA); and animals were tested for depressive-like behaviours. Morphological and electrophysiological studies were conducted to investigate the functional integrity of stimulation-induced neuroprotection effects in this model. Results and Discussion: In electrophysiology, we found responsive retinastimulation-induced neuronal activities in the primary visual cortex (V1) of S334ter-line-3 rats compared to sham animals, indicating that stimulation enhanced neuroprotection on the functional connectivity between retina and V1. In this S334ter-line-3 model, animals demonstrated higher level of anxiety-like responses in the cylinder test, open-field and home-cage emergence tasks; and these anxiogenic-like behaviours were completely abolished after TES treatment. Interestingly, S334ter-line-3 animals with TES showed a remarkable reduction of forced swim immobility, indicating antidepressant-like effects. Conclusion: Our study demonstrated that TES induced antidepressant-like effects in S334ter-line-3 rat model, and this approach could be a potential therapy for patients suffering from depression.