title: Chronological changes in astrocytes induced by chronic electrical sensorimotor cortex stimulation in rats.
abstract: Motor cortex stimulation (MCS) is a treatment option for various disorders such as medically refractory pain, poststroke hemiplegia, and movement disorders. However, the exact mechanisms underlying its effects remain unknown. In this study, the effects of long-term chronic MCS were investigated by observing changes in astrocytes. A quadripolar stimulation electrode was implanted on the dura over the sensorimotor cortex of adult rats, and the cortex was continuously stimulated for 3 hours, 1 week, 4 weeks, and 8 weeks. Immunohistochemical staining of microglia (ionized calcium-binding adaptor molecule 1 [Iba1] staining) and astrocytes (glial fibrillary acidic protein [GFAP] staining), and neuronal degeneration histochemistry (Fluoro-Jade B staining) were carried out to investigate the morphological changes following long-term chronic MCS. Iba1 staining and Fluoro-Jade B staining showed no evidence of Iba1-positive microglial changes or neurodegeneration. Following continuous MCS, GFAP-positive astrocytes were enlarged and their number increased in the cortex and the thalamus of the stimulated hemisphere. These findings indicate that chronic electrical stimulation can continuously activate astrocytes and result in morphological and quantitative changes. These changes may be involved in the mechanisms underlying the neuroplasticity effect induced by MCS.
authors.affiliation: Division of Neurosurgery, Department of Neurological Surgery, Nihon University School of Medicine, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Morishita
authors.forename: Akiko
authors.initials: A
authors.lastname: Yamashita
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Katayama
authors.forename: Hideki
authors.initials: H
authors.lastname: Oshima
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nishizaki
authors.forename: Katsunori
authors.initials: K
authors.lastname: Shijo
authors.forename: Chikashi
authors.initials: C
authors.lastname: Fukaya
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000502:physiology*; D001927:Brain Diseases / Q000628:therapy*; D004599:Electric Stimulation Therapy / Q000009:adverse effects / Q000379:methods*; D006179:Gyrus Cinguli / Q000166:cytology / Q000502:physiology; D008297:Male; D009044:Motor Cortex / Q000166:cytology / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000502:physiology*; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology; D016896:Treatment Outcome