Preclinical Validation of Electrodes for Single Anodal Transcranial Direct Current Stimulation on Rat Model With Chronic Stress-Induced Depression

Abstract

Transcranial direct current stimulation (tDCS) is an effective and safe non-invasive brain stimulation (NIBS) procedures to modulate neuronal excitability. The present preclinical study was carried out to validate the impact of the innovative high definition fabricated spiking Au/AgCI electrodes via non-invasive tDCS procedure on rat model with depression-like behaviour. In present study, chronic stress induced depression like behaviour rat model was developed over a period of 14-days. Further, the after-effects of NIBS procedures were investigated by providing a tDCS dose (2.00mA × 5.00minutes) by placing the electrodes on the interested region of the rat brain. The current study was performed in healthy rats, control rats with depression-like behaviour, and tDCS treated rats, which were used to examine the differential after-effects of tDCS dose. After single tDCS dose, a significant increase in average band power of electroencephalogram (EEG) has been observed (F(2, 15) = 8.376; P = 0.0036) alongside a significant increase in the glutamate level of hippocampus (F(2, 15) = 8.919; P = 0.0028), a significant reduction in immobility time (F(2, 15) = 7.552; P = 0.0054), and a significant increase in the percentage sucrose intake has been observed (F(2,15) = 5.941; P = 0.0126). Additionally, immunohistochemistry (IHC) showed a significant increase in theIba1 protein expression in microglia cell in the both cortex and hippocampus region (P < 0.05). Hence, the fabricated electrodes can deliver a tDCS dose that can penetrate up to the cortex and hippocampus regions from the surface of brain non-invasively within tolerable and safety limits.