Repeated transcranial direct current stimulation improves cognitive dysfunction and synaptic plasticity deficit in the prefrontal cortex of streptozotocin-induced diabetic rats
Journal
Brain Stimulation
Journal Volume
10
Journal Issue
6
Pages
1079
Date Issued
2017-11-01
Author(s)
Wu, Yi Jen
Lin, Chou Ching
Yeh, Che Ming
Chien, Miao Er
Tsao, Ming Chung
Huang, Chin Wei
Hsu, Kuei Sen
Abstract
Background Cognitive dysfunction is commonly observed in diabetic patients. We have previously reported that anodal transcranial direct current stimulation (tDCS) over the dorsolateral prefrontal cortex can facilitate visuospatial working memory in diabetic patients with concomitant diabetic peripheral neuropathy and mild cognitive impairment, but the underlying mechanisms remain unclear. Objective We investigated the cellular mechanisms underlying the effect of tDCS on cognitive decline in streptozotocin (STZ)-induced diabetic rats. Methods STZ-induced diabetic rats were subjected to either repeated anodal tDCS or sham stimulation over the medial prefrontal cortex (mPFC). Spatial working memory performance in delayed nonmatch-to-place T maze task (DNMT), the induction of long-term potentiation (LTP) in the mPFC, and dendritic morphology of Golgi-stained pyramidal neurons in the mPFC were assessed. Results Repeated applications of prefrontal anodal tDCS improved spatial working memory performance in DNMT and restored the impaired mPFC LTP of diabetic rats. The mPFC of tDCS-treated diabetic rats exhibited higher levels of brain-derived neurotrophic factor (BDNF) protein and N-Methyl-D-aspartate receptor (NMDAR) subunit mRNA and protein compared to sham stimulation group. Furthermore, anodal tDCS significantly increased dendritic spine density on the apical dendrites of mPFC layer V pyramidal cells in diabetic rats, whereas the complexity of basal and apical dendritic trees was unaltered. Conclusions Our findings suggest that repeated anodal tDCS may improve spatial working memory performance in streptozotocin-induced diabetic rats through augmentation of synaptic plasticity that requires BDNF secretion and transcription/translation of NMDARs in the mPFC, and support the therapeutic potential of tDCS for cognitive decline in diabetes mellitus patients.
Subjects
Brain-derived neurotrophic factor | Cognitive function | Diabetes mellitus | Medial prefrontal cortex | N-Methyl-D-aspartate receptor | Transcranial direct current stimulation
Type
journal article