Dual-tDCS Ameliorates Cerebral Injury and Promotes Motor Function Recovery via cGAS-STING Signaling Pathway in a Rat Model of Ischemic Stroke

Ischemic stroke is one of the leading causes of death and disability. Dual transcranial direct current stimulation (dual-tDCS) is a promising intervention to treat ischemic stroke, but its efficacy and underlying mechanism remain to be verified. Cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway has recently emerged as a key mediator in cerebral injury. However, little is known about the effect of cGAS-STING on neuronal damage in ischemic stroke, and it remains to be studied whether the cGAS-STING pathway is involved in tDCS intervention for ischemic stroke. Therefore, we aimed to investigate whether dual-tDCS can alleviate ischemic brain injury in a rat model of ischemic stroke and if so, whether via cGAS-STING pathway. Middle cerebral artery occlusion (MCAO) was employed to induce a rat model of ischemic stroke. Male SD rats weighing 250-280 g were randomly assigned to the Sham, MCAO, Dual-tDCS, Dual-tDCS + RU.521, and Dual-tDCS + 2'3'-cGAMP groups, with 10 rats in each group completing the experiment. Behavioral, morphological, MRI, and molecular biological methods were performed. We found that the cGAS-STING pathway was activated and expressed in neurons after MCAO. Dual-tDCS improved motor function and infarct volume, inhibited neuronal apoptosis, promoted the expression of neurotrophins (BDNF and NGF), CD31, and VEGF, and suppressed inflammation reaction after MCAO via the cGAS-STING pathway. Taken together, dual-tDCS may improve MCAO-induced brain injury and promote the recovery of motor function, resulting from the inhibition of neuronal apoptosis and inflammation reaction, as well as promotion of the expression of nerve plasticity- and angiogenesis-related proteins, via cGAS-STING pathway.