title: Intensity-dependent effects of repetitive anodal transcranial direct current stimulation on learning and memory in a rat model of Alzheimer's disease.
abstract: Single-session anodal transcranial direct current stimulation (tDCS) can improve the learning-memory function of patients with Alzheimer's disease (AD). After-effects of tDCS can be more significant if the stimulation is repeated regularly in a period. Here the behavioral and the histologic effects of the repetitive anodal tDCS on a rat model of AD were investigated. Sprague-Dawley rats were divided into 6 groups, the sham group, the β-amyloid (Aβ) group, the Aβ+20μA tDCS group, the Aβ+60μA tDCS group, the Aβ+100μA tDCS group and the Aβ+200μA tDCS group. Bilateral hippocampus of the rats in the Aβ group and the Aβ+tDCS groups were lesioned by Aβ1-40 to produce AD models. One day after drug injection, repetitive anodal tDCS (10 sessions in two weeks, 20min per session) was applied to the frontal cortex of the rats in the tDCS groups, while sham stimulation was applied to the Aβ group and the sham group. The spatial learning and memory capability of the rats were tested by Morris water maze. Bielschowsky's silver staining, Nissl's staining, choline acetyltransferase (ChAT) and glial-fibrillary-acidic protein (GFAP) immunohistochemistry of the hippocampus were conducted for histologic analysis. Results show in the Morris water maze task, rats in the Aβ+100μA and the Aβ+200μA tDCS groups had shorter escape latency and larger number of crossings on the platform. Significant histologic differences were observed in the Aβ+100μA and the Aβ+200μA tDCS groups compared to the Aβ group. The behavioral and the histological experiments indicate that the proposed repetitive anodal tDCS treatment can protect spatial learning and memory dysfunction of Aβ1-40-lesioned AD rats.
authors.affiliation: Bioengineering College of Chongqing University, Chongqing 400030, China. Electronic address: 20121902010t@cqu.edu.cn.
authors.forename: Xuehong
authors.initials: X
authors.lastname: Yu
authors.affiliation: Department of Electrical and Computer Engineering, University of Nevada, Las Vegas, Las Vegas, NV 89154-4026, USA. Electronic address: liy10@unlv.nevada.edu.
authors.forename: Yiyan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Neurobiology, Chongqing Key Laboratory of Neurobiology, Third Military Medical University, Chongqing 400038, China. Electronic address: just_zhong2006@hotmail.com.
authors.forename: Huizhong
authors.initials: H
authors.lastname: Wen
authors.affiliation: Bioengineering College of Chongqing University, Chongqing 400030, China. Electronic address: 20121913077@cqu.edu.cn.
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Bioengineering College of Chongqing University, Chongqing 400030, China. Electronic address: xltian@cqu.edu.cn.
authors.forename: Xuelong
authors.initials: X
authors.lastname: Tian
mesh_terms: D000544:Alzheimer Disease / Q000139:chemically induced / Q000503:physiopathology / Q000628:therapy*; D016229:Amyloid beta-Peptides / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D005625:Frontal Lobe / Q000473:pathology / Q000503:physiopathology*; D018782:Maze Learning / Q000502:physiology*; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology*; D011597:Psychomotor Performance; D051381:Rats; D017207:Rats, Sprague-Dawley; D065852:Spatial Memory / Q000502:physiology*; D065908:Transcranial Direct Current Stimulation / Q000009:adverse effects / Q000379:methods*
chemical_list: D016229:Amyloid beta-Peptides; D010446:Peptide Fragments; C078592:amyloid beta-protein (1-40)
keywords: Alzheimer’s disease; Repetitive anodal stimulation; Spatial learning and memory; Transcranial direct current stimulation