title: Vagus Nerve Stimulation Exerts the Neuroprotective Effects in Obese-Insulin Resistant Rats, Leading to the Improvement of Cognitive Function.
abstract: Vagus nerve stimulation (VNS) therapy was shown to improve peripheral insulin sensitivity. However, the effects of chronic VNS therapy on brain insulin sensitivity, dendritic spine density, brain mitochondrial function, apoptosis and cognition in obese-insulin resistant subjects have never been investigated. Male Wistar rats (n = 24) were fed with either a normal diet (n = 8) or a HFD (n = 16) for 12 weeks. At week 13, HFD-fed rats were divided into 2 groups (n = 8/group). Each group was received either sham therapy or VNS therapy for an additional 12 weeks. At the end of treatment, cognitive function, metabolic parameters, brain insulin sensitivity, brain mitochondrial function, brain apoptosis, and dendritic spines were determined in each rat. The HFD-fed with Sham therapy developed brain insulin resistance, brain oxidative stress, brain inflammation, and brain apoptosis, resulting in the cognitive decline. The VNS group showed an improvement in peripheral and brain insulin sensitivity. VNS treatment attenuated brain mitochondrial dysfunction and cell apoptosis. In addition, VNS therapy increased dendritic spine density and improved cognitive function. These findings suggest that VNS attenuates cognitive decline in obese-insulin resistant rats by attenuating brain mitochondrial dysfunction, improving brain insulin sensitivity, decreasing cell apoptosis, and increasing dendritic spine density.
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Titikorn
authors.initials: T
authors.lastname: Chunchai
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Bencharunan
authors.initials: B
authors.lastname: Samniang
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Jirapas
authors.initials: J
authors.lastname: Sripetchwandee
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Hiranya
authors.initials: H
authors.lastname: Pintana
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Wanpitak
authors.initials: W
authors.lastname: Pongkan
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Sirinart
authors.initials: S
authors.lastname: Kumfu
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Krekwit
authors.initials: K
authors.lastname: Shinlapawittayatorn
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Emerging Therapies, Cyberonics Inc, Houston, Texas, USA.
authors.forename: Bruce H
authors.initials: BH
authors.lastname: KenKnight
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Cardiac Electrophysiology Research and Training Center, Department of Physiology, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Nipon
authors.initials: N
authors.lastname: Chattipakorn
authors.affiliation: Neurophysiology Unit, Cardiac Electrophysiology Research and Training Center, Faculty of Medicine, Chiang Mai University, Chiang Mai, 50200, Thailand.|Department of Oral Biology and Diagnostic Sciences, Faculty of Dentistry, Chiang Mai University, Chiang Mai, 50200, Thailand.
authors.forename: Siriporn C
authors.initials: SC
authors.lastname: Chattipakorn
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight; D001921:Brain / Q000378:metabolism / Q000473:pathology; D002784:Cholesterol / Q000097:blood; D003071:Cognition; D059305:Diet, High-Fat / Q000009:adverse effects; D006946:Hyperinsulinism / Q000209:etiology / Q000628:therapy; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000523:psychology*; D018384:Oxidative Stress; D051381:Rats; D017208:Rats, Wistar; D055536:Vagus Nerve Stimulation / Q000379:methods
chemical_list: D001786:Blood Glucose; D007328:Insulin; D002784:Cholesterol